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Note
titleBug for expression caching when UDF nested in UDF or function

When hive.cache.expr.evaluation is set to true (which is the default) a UDF can give incorrect results if it is nested in another UDF or a Hive function. This bug affects releases 0.12.0, 0.13.0, and 0.13.1. Release 0.14.0 fixed the bug (HIVE-7314).

The problem relates to the UDF's implementation of the getDisplayString method, as discussed in the Hive user mailing list.

Built-in Operators

Anchor
Operators precedences
Operators precedences
Anchor
Operators Precedences
Operators Precedences
Operators Precedences

Example

Operators

Description

A[B] , A.identifierbracket_op([]), dot(.)element selector, dot

-A

unary(+), unary(-), unary(~)

unary prefix operators

A IS [NOT] (NULL|TRUE|FALSE)IS NULL,IS NOT NULL, ...unary suffix

A ^ B

bitwise xor(^)

bitwise xor

A * Bstar(*), divide(/), mod(%), div(DIV)multiplicative operators
A + Bplus(+), minus(-)

additive operators

A || Bstring concatenate(||)string concatenate
A & Bbitwise and(&)bitwise and
A | Bbitwise or(|)bitwise or

Relational Operators

The following operators compare the passed operands and generate a TRUE or FALSE value depending on whether the comparison between the operands holds.

Operator

Operand types

Description

A = B

All primitive types

TRUE if expression A is equal to expression B otherwise FALSE.

A == BAll primitive typesSynonym for the = operator.

A <=> B

All primitive types

Returns same result with EQUAL(=) operator for non-null operands, but returns TRUE if both are NULL, FALSE if one of the them is NULL. (As of version 0.9.0.)

A <> B

All primitive types

NULL if A or B is NULL, TRUE if expression A is NOT equal to expression B, otherwise FALSE.

A != B

All primitive types

Synonym for the <> operator.

A < B

All primitive types

NULL if A or B is NULL, TRUE if expression A is less than expression B, otherwise FALSE.

A <= B

All primitive types

NULL if A or B is NULL, TRUE if expression A is less than or equal to expression B, otherwise FALSE.

A > B

All primitive types

NULL if A or B is NULL, TRUE if expression A is greater than expression B, otherwise FALSE.

A >= B

All primitive types

NULL if A or B is NULL, TRUE if expression A is greater than or equal to expression B, otherwise FALSE.

A [NOT] BETWEEN B AND C

All primitive types

NULL if A, B or C is NULL, TRUE if A is greater than or equal to B AND A less than or equal to C, otherwise FALSE. This can be inverted by using the NOT keyword. (As of version 0.9.0.)

A IS NULL

All types

TRUE if expression A evaluates to NULL, otherwise FALSE.

A IS NOT NULL

All types

FALSE if expression A evaluates to NULL, otherwise TRUE.

A IS [NOT] (TRUE|FALSE)Boolean types

Evaluates to TRUE only if A mets the condition. (since:3.0.0 )
Note: NULL is UNKNOWN, and because of that (UNKNOWN IS TRUE) and (UNKNOWN IS FALSE) both evaluates to FALSE.

A [NOT] LIKE B

strings

NULL if A or B is NULL, TRUE if string A matches the SQL simple regular expression B, otherwise FALSE. The comparison is done character by character. The _ character in B matches any character in A (similar to . in posix regular expressions) while the % character in B matches an arbitrary number of characters in A (similar to .* in posix regular expressions). For example, 'foobar' like 'foo' evaluates to FALSE whereas 'foobar' like 'foo_ _ _' evaluates to TRUE and so does 'foobar' like 'foo%'.

A RLIKE B

strings

NULL if A or B is NULL, TRUE if any (possibly empty) substring of A matches the Java regular expression B, otherwise FALSE. For example, 'foobar' RLIKE 'foo' evaluates to TRUE and so does 'foobar' RLIKE '^f.*r$'.

A REGEXP B

strings

Same as RLIKE.

...

Operator

Operand types

Description

A + B

All number types

Gives the result of adding A and B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands. For example since every integer is a float, therefore float is a containing type of integer so the + operator on a float and an int will result in a float.

A - B

All number types

Gives the result of subtracting B from A. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands.

A * B

All number types

Gives the result of multiplying A and B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands. Note that if the multiplication causing overflow, you will have to cast one of the operators to a type higher in the type hierarchy.

A / B

All number types

Gives the result of dividing A by B. The result is a double type in most cases. When A and B are both integers, the result is a double type except when the hive.compat configuration parameter is set to "0.13" or "latest" in which case the result is a decimal type.

A DIV BInteger typesGives the integer part resulting from dividing A by B. E.g 17 div 3 results in 5.

A % B

All number types

Gives the reminder resulting from dividing A by B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands.

A & B

All number types

Gives the result of bitwise AND of A and B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands.

A | B

All number types

Gives the result of bitwise OR of A and B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands.

A ^ B

All number types

Gives the result of bitwise XOR of A and B. The type of the result is the same as the common parent(in the type hierarchy) of the types of the operands.

~A

All number types

Gives the result of bitwise NOT of A. The type of the result is the same as the type of A.

...

Operator

Operand types

Description

A AND B

boolean

TRUE if both A and B are TRUE, otherwise FALSE. NULL if A or B is NULL.

A && B

boolean

Same as A AND B.

A OR B

boolean

TRUE if either A or B or both are TRUE, FALSE OR NULL is NULL, otherwise FALSE.

A || B

boolean

Same as A OR B.

NOT A

boolean

TRUE if A is FALSE or NULL if A is NULL. Otherwise FALSE.

! A

boolean

Same as NOT A.

A IN (val1, val2, ...)

boolean

TRUE if A is equal to any of the values. As of Hive 0.13 subqueries are supported in IN statements.

A NOT IN (val1, val2, ...)

boolean

TRUE if A is not equal to any of the values. As of Hive 0.13 subqueries are supported in NOT IN statements.

[NOT] EXISTS (subquery)

 

TRUE if the the subquery returns at least one row. Supported as of Hive 0.13.

String Operators

 

Operator

Operand types

Description

A || B

strings 

Concatenates the operands - shorthand for concat(A,B) . Supported as of Hive 2.2.0.

Complex Type Constructors

...

Return Type

Name (Signature)

Description

DOUBLE

round(DOUBLE a)

Returns the rounded BIGINT value of a.

DOUBLE

round(DOUBLE a, INT d)

Returns a rounded to d decimal places.

DOUBLEbround(DOUBLE a)Returns the rounded BIGINT value of a using HALF_EVEN rounding mode (as of Hive 1.3.0, 2.0.0). Also known as Gaussian rounding or bankers' rounding. Example: bround(2.5) = 2, bround(3.5) = 4.
DOUBLEbround(DOUBLE a, INT d)Returns a rounded to d decimal places using HALF_EVEN rounding mode (as of Hive 1.3.0, 2.0.0). Example: bround(8.25, 1) = 8.2, bround(8.35, 1) = 8.4.

BIGINT

floor(DOUBLE a)

Returns the maximum BIGINT value that is equal to or less than a.

BIGINT

ceil(DOUBLE a), ceiling(DOUBLE a)

Returns the minimum BIGINT value that is equal to or greater than a.

DOUBLE

rand(), rand(INT seed)

Returns a random number (that changes from row to row) that is distributed uniformly from 0 to 1. Specifying the seed will make sure the generated random number sequence is deterministic.

DOUBLE

exp(DOUBLE a), exp(DECIMAL a)

Returns ea where e is the base of the natural logarithm. Decimal version added in Hive 0.13.0.

DOUBLE

ln(DOUBLE a), ln(DECIMAL a)

Returns the natural logarithm of the argument a. Decimal version added in Hive 0.13.0.

DOUBLE

log10(DOUBLE a), log10(DECIMAL a)

Returns the base-10 logarithm of the argument a. Decimal version added in Hive 0.13.0.

DOUBLE

log2(DOUBLE a), log2(DECIMAL a)

Returns the base-2 logarithm of the argument a. Decimal version added in Hive 0.13.0.

DOUBLE

log(DOUBLE base, DOUBLE a)

log(DECIMAL base, DECIMAL a)

Returns the base-base logarithm of the argument a. Decimal versions added in Hive 0.13.0.

DOUBLE

pow(DOUBLE a, DOUBLE p), power(DOUBLE a, DOUBLE p)

Returns ap.

DOUBLE

sqrt(DOUBLE a), sqrt(DECIMAL a)

Returns the square root of a. Decimal version added in Hive 0.13.0.

STRING

bin(BIGINT a)

Returns the number in binary format (see http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_bin).

STRING

hex(BIGINT a) hex(STRING a) hex(BINARY a)

If the argument is an INT or binary, hex returns the number as a STRING in hexadecimal format. Otherwise if the number is a STRING, it converts each character into its hexadecimal representation and returns the resulting STRING. (See http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_hex, BINARY version as of Hive 0.12.0.)

BINARY

unhex(STRING a)

Inverse of hex. Interprets each pair of characters as a hexadecimal number and converts to the byte representation of the number. (BINARY version as of Hive 0.12.0, used to return a string.)

STRING

conv(BIGINT num, INT from_base, INT to_base), conv(STRING num, INT from_base, INT to_base)

Converts a number from a given base to another (see http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_conv).

DOUBLE

abs(DOUBLE a)

Returns the absolute value.

INT or DOUBLE

pmod(INT a, INT b), pmod(DOUBLE a, DOUBLE b)

Returns the positive value of a mod b.

DOUBLE

sin(DOUBLE a), sin(DECIMAL a)

Returns the sine of a (a is in radians). Decimal version added in Hive 0.13.0.

DOUBLE

asin(DOUBLE a), asin(DECIMAL a)

Returns the arc sin of a if -1<=a<=1 or NULL otherwise. Decimal version added in Hive 0.13.0.

DOUBLE

cos(DOUBLE a), cos(DECIMAL a)

Returns the cosine of a (a is in radians). Decimal version added in Hive 0.13.0.

DOUBLE

acos(DOUBLE a), acos(DECIMAL a)

Returns the arccosine of a if -1<=a<=1 or NULL otherwise. Decimal version added in Hive 0.13.0.

DOUBLE

tan(DOUBLE a), tan(DECIMAL a)

Returns the tangent of a (a is in radians). Decimal version added in Hive 0.13.0.

DOUBLE

atan(DOUBLE a), atan(DECIMAL a)

Returns the arctangent of a. Decimal version added in Hive 0.13.0.

DOUBLE

degrees(DOUBLE a), degrees(DECIMAL a)

Converts value of a from radians to degrees. Decimal version added in Hive 0.13.0.

DOUBLE

radians(DOUBLE a), radians(DOUBLE a)

Converts value of a from degrees to radians. Decimal version added in Hive 0.13.0.

INT or DOUBLE

positive(INT a), positive(DOUBLE a)

Returns a.

INT or DOUBLE

negative(INT a), negative(DOUBLE a)

Returns -a.

DOUBLE or INT

sign(DOUBLE a), sign(DECIMAL a)

Returns the sign of a as '1.0' (if a is positive) or '-1.0' (if a is negative), '0.0' otherwise. The decimal version returns INT instead of DOUBLE. Decimal version added in Hive 0.13.0.

DOUBLE

e()

Returns the value of e.

DOUBLE

pi()

Returns the value of pi.

BIGINTfactorial(INT a)Returns the factorial of a (as of Hive 1.2.0). Valid a is [0..20].
DOUBLEcbrt(DOUBLE a)Returns the cube root of a double value (as of Hive 1.2.0).

INT

BIGINT

shiftleft(TINYINT|SMALLINT|INT a, INT b)

shiftleft(BIGINT a, INT b)

Bitwise left shift (as of Hive 1.2.0). Shifts a b positions to the left.

Returns int for tinyint, smallint and int a. Returns bigint for bigint a.

INT

BIGINT

shiftright(TINYINT|SMALLINT|INT a, INT b)

shiftright(BIGINT a, INT b)

Bitwise right shift (as of Hive 1.2.0). Shifts a b positions to the right.

Returns int for tinyint, smallint and int a. Returns bigint for bigint a.

INT

BIGINT

shiftrightunsigned(TINYINT|SMALLINT|INT a, INT b),

shiftrightunsigned(BIGINT a, INT b)

Bitwise unsigned right shift (as of Hive 1.2.0). Shifts a b positions to the right.

Returns int for tinyint, smallint and int a. Returns bigint for bigint a.

Tgreatest(T v1, T v2, ...)Returns the greatest value of the list of values (as of Hive 1.1.0). Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with ">" operator (as of Hive 2.0.0).
Tleast(T v1, T v2, ...)Returns the least value of the list of values (as of Hive 1.1.0). Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with "<" operator (as of Hive 2.0.0).
INTwidth_bucket(NUMERIC expr, NUMERIC min_value, NUMERIC max_value, INT num_buckets)

Returns an integer between 0 and num_buckets+1 by mapping expr into the ith equally sized bucket. Buckets are made by dividing [min_value, max_value] into equally sized regions. If expr < min_value, return 1, if expr > max_value return num_buckets+1. See https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions214.htm (as of Hive 3.0.0)

Mathematical Functions and Operators for Decimal Datatypes

...

Return Type

Name(Signature)

Description

string

from_unixtime(bigint unixtime[, string format])

Converts the number of seconds from unix epoch (1970-01-01 00:00:00 UTC) to a string representing the timestamp of that moment in the current system time zone in the format of "1970-01-01 00:00:00".

bigint

unix_timestamp()

Gets current Unix timestamp in seconds. This function is not deterministic and its value is not fixed for the scope of a query execution, therefore prevents proper optimization of queries - this has been deprecated since 2.0 in favour of CURRENT_TIMESTAMP constant.

bigint

unix_timestamp(string date)

Converts time string in format yyyy-MM-dd HH:mm:ss to Unix timestamp (in seconds), using the default timezone and the default locale, return 0 if fail: unix_timestamp('2009-03-20 11:30:01') = 1237573801

bigint

unix_timestamp(string date, string pattern)

Convert time string with given pattern (see [http://docs.oracle.com/javase/tutorial/i18n/format/simpleDateFormat.html]) to Unix time stamp (in seconds), return 0 if fail: unix_timestamp('2009-03-20', 'yyyy-MM-dd') = 1237532400.

pre 2.1.0: string

2.1.0 on: date

to_date(string timestamp)

Returns the date part of a timestamp string (pre-Hive 2.1.0): to_date("1970-01-01 00:00:00") = "1970-01-01". As of Hive 2.1.0, returns a date object.

Prior to Hive 2.1.0 (HIVE-13248) the return type was a String because no Date type existed when the method was created.

int

year(string date)

Returns the year part of a date or a timestamp string: year("1970-01-01 00:00:00") = 1970, year("1970-01-01") = 1970.

int

quarter(date/timestamp/string)Returns the quarter of the year for a date, timestamp, or string in the range 1 to 4 (as of Hive 1.3.0). Example: quarter('2015-04-08') = 2.

int

month(string date)

Returns the month part of a date or a timestamp string: month("1970-11-01 00:00:00") = 11, month("1970-11-01") = 11.

int

day(string date) dayofmonth(date)

Returns the day part of a date or a timestamp string: day("1970-11-01 00:00:00") = 1, day("1970-11-01") = 1.

int

hour(string date)

Returns the hour of the timestamp: hour('2009-07-30 12:58:59') = 12, hour('12:58:59') = 12.

int

minute(string date)

Returns the minute of the timestamp.

int

second(string date)

Returns the second of the timestamp.

int

weekofyear(string date)

Returns the week number of a timestamp string: weekofyear("1970-11-01 00:00:00") = 44, weekofyear("1970-11-01") = 44.

int

extract(field FROM source)

Retrieve fields such as days or hours from source (as of Hive 2.2.0). Source must be a date, timestamp, interval or a string that can be converted into either a date or timestamp. Supported fields include: day, dayofweek, hour, minute, month, quarter, second, week and year.

Examples:

  1. select extract(month from "2016-10-20") results in 10.

  2. select extract(hour from "2016-10-20 05:06:07") results in 5.

  3. select extract(dayofweek from "2016-10-20 05:06:07") results in 5.

  4. select extract(month from interval '1-3' year to month) results in 3.

  5. select extract(minute from interval '3 12:20:30' day to second) results in 20.

int

datediff(string enddate, string startdate)

Returns the number of days from startdate to enddate: datediff('2009-03-01', '2009-02-27') = 2.

pre 2.1.0: string

2.1.0 on: date

date_add(date/timestamp/string startdate, tinyint/smallint/int days)

Adds a number of days to startdate: date_add('2008-12-31', 1) = '2009-01-01'.

Prior to Hive 2.1.0 (HIVE-13248) the return type was a String because no Date type existed when the method was created.

pre 2.1.0: string

2.1.0 on: date

date_sub(date/timestamp/string startdate, tinyint/smallint/int days)

Subtracts a number of days to startdate: date_sub('2008-12-31', 1) = '2008-12-30'.

Prior to Hive 2.1.0 (HIVE-13248) the return type was a String because no Date type existed when the method was created.

timestamp

from_utc_timestamp(timestamp{any primitive type}*, string timezone)

Assumes given timestamp is UTC and converts to Coverts a timestamp* in UTC to a given timezone (as of Hive 0.8.0). For example, * timestamp is a primitive type, including timestamp/date, tinyint/smallint/int/bigint, float/double and decimal. Fractional values are considered as seconds. Integer values are considered as milliseconds.. E.g from_utc_timestamp(2592000.0,'PST'), from_utc_timestamp(2592000000,'PST') and from_utc_timestamp(timestamp '1970-01-01 0830 16:00:00','PST') returns all return the timestamp 1970-01-01 0030 08:00:00.

timestamp

to_utc_timestamp(timestamp{any primitive type} ts, string timezone)

Assumes given Coverts a timestamp is * in a given timezone and converts to UTC (as of Hive 0.8.0). For example, * timestamp is a primitive type, including timestamp/date, tinyint/smallint/int/bigint, float/double and decimal. Fractional values are considered as seconds. Integer values are considered as milliseconds.. E.g to_utc_timestamp(2592000.0,'PST'), to_utc_timestamp(2592000000,'PST') and to_utc_timestamp(timestamp '1970-01-01 0030 16:00:00','PST') returns all return the timestamp 1970-01-01 0831 00:00:00.

datecurrent_date

Returns the current date at the start of query evaluation (as of Hive 1.2.0). All calls of current_date within the same query return the same value.

timestampcurrent_timestamp

Returns the current timestamp at the start of query evaluation (as of Hive 1.2.0). All calls of current_timestamp within the same query return the same value.

stringadd_months(string start_date, int num_months)

Returns the date that is num_months after start_date (as of Hive 1.1.0). start_date is a string, date or timestamp. num_months is an integer. The time part of start_date is ignored. If start_date is the last day of the month or if the resulting month has fewer days than the day component of start_date, then the result is the last day of the resulting month. Otherwise, the result has the same day component as start_date.

stringlast_day(string date)Returns the last day of the month which the date belongs to (as of Hive 1.1.0). date is a string in the format 'yyyy-MM-dd HH:mm:ss' or 'yyyy-MM-dd'. The time part of date is ignored.
stringnext_day(string start_date, string day_of_week)Returns the first date which is later than start_date and named as day_of_week (as of Hive 1.2.0). start_date is a string/date/timestamp. day_of_week is 2 letters, 3 letters or full name of the day of the week (e.g. Mo, tue, FRIDAY). The time part of start_date is ignored. Example: next_day('2015-01-14', 'TU') = 2015-01-20.
stringtrunc(string date, string format)Returns date truncated to the unit specified by the format (as of Hive 1.2.0). Supported formats: MONTH/MON/MM, YEAR/YYYY/YY. Example: trunc('2015-03-17', 'MM') = 2015-03-01.
doublemonths_between(date1, date2)Returns number of months between dates date1 and date2 (as of Hive 1.2.0). If date1 is later than date2, then the result is positive. If date1 is earlier than date2, then the result is negative. If date1 and date2 are either the same days of the month or both last days of months, then the result is always an integer. Otherwise the UDF calculates the fractional portion of the result based on a 31-day month and considers the difference in time components date1 and date2. date1 and date2 type can be date, timestamp or string in the format 'yyyy-MM-dd' or 'yyyy-MM-dd HH:mm:ss'. The result is rounded to 8 decimal places. Example: months_between('1997-02-28 10:30:00', '1996-10-30') = 3.94959677
stringdate_format(date/timestamp/string ts, string fmt)

Converts a date/timestamp/string to a value of string in the format specified by the date format fmt (as of Hive 1.2.0). Supported formats are Java SimpleDateFormat formats https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html. The second argument fmt should be constant. Example: date_format('2015-04-08', 'y') = '2015'.

date_format can be used to implement other UDFs, e.g.:

  • dayname(date) is date_format(date, 'EEEE')
  • dayofyear(date) is date_format(date, 'D')

...

Return Type

Name(Signature)

Description

T

if(boolean testCondition, T valueTrue, T valueFalseOrNull)

Returns valueTrue when testCondition is true, returns valueFalseOrNull otherwise.

booleanisnull( a )Returns true if a is NULL and false otherwise.
booleanisnotnull ( a )Returns true if a is not NULL and false otherwise.
Tnvl(T value, T default_value)Returns default value if value is null else returns value (as of HIve 0.11).

T

COALESCE(T v1, T v2, ...)

Returns the first v that is not NULL, or NULL if all v's are NULL.

T

CASE a WHEN b THEN c [WHEN d THEN e]* [ELSE f] END

When a = b, returns c; when a = d, returns e; else returns f.

T

CASE WHEN a THEN b [WHEN c THEN d]* [ELSE e] END

When a = true, returns b; when c = true, returns d; else returns e.

Tnullif( a, b )

Returns NULL if a=b; otherwise returns a (as of Hive 2.2.0).

Shorthand for: CASE WHEN a = b then NULL else a

voidassert_true(boolean condition)Throw an exception if 'condition' is not true, otherwise return null (as of Hive 0.8.0). For example, select assert_true (2<1).

String Functions

The following built-in String functions are supported in Hive:

Return Type

Name(Signature)

Description

int

ascii(string str)

Returns the numeric value of the first character of str.

string

base64(binary bin)

Converts the argument from binary to a base 64 string (as of Hive 0.12.0).

intcharacter_length(string str)Returns the number of UTF-8 characters contained in str (as of Hive 2.2.0). The function char_length is shorthand for this function.
stringchr(bigint|double A)Returns the ASCII character having the binary equivalent to A (as of Hive 1.3.0 and 2.1.0). If A is larger than 256 the result is equivalent to chr(A % 256). Example: select chr(88); returns "X".

string

concat(string|binary A, string|binary B...)

Returns the string or bytes resulting from concatenating the strings or bytes passed in as parameters in order. For example, concat('foo', 'bar') results in 'foobar'. Note that this function can take any number of input strings.

array<struct<string,double>>

context_ngrams(array<array<string>>, array<string>, int K, int pf)

Returns the top-k contextual N-grams from a set of tokenized sentences, given a string of "context". See StatisticsAndDataMining for more information.

string

concat_ws(string SEP, string A, string B...)

Like concat() above, but with custom separator SEP.

string

concat_ws(string SEP, array<string>)

Like concat_ws() above, but taking an array of strings. (as of Hive 0.9.0)

string

decode(binary bin, string charset)

Decodes the first argument into a String using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null. (As of Hive 0.12.0.)

stringelt(N int,str1 string,str2 string,str3 string,...)

Return string at index number. For example elt(2,'hello','world') returns 'world'. Returns NULL if N is less than 1 or greater than the number of arguments.

(see https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_elt)

binary

encode(string src, string charset)

Encodes the first argument into a BINARY using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null. (As of Hive 0.12.0.)

intfield(val T,val1 T,val2 T,val3 T,...)

Returns the index of val in the val1,val2,val3,... list or 0 if not found. For example field('world','say','hello','world') returns 3.
All primitive types are supported, arguments are compared using str.equals(x). If val is NULL, the return value is 0.

(see https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_field)

int

find_in_set(string str, string strList)

Returns the first occurance of str in strList where strList is a comma-delimited string. Returns null if either argument is null. Returns 0 if the first argument contains any commas. For example, find_in_set('ab', 'abc,b,ab,c,def') returns 3.

string

format_number(number x, int d)

Formats the number X to a format like '#,###,###.##', rounded to D decimal places, and returns the result as a string. If D is 0, the result has no decimal point or fractional part. (As of Hive 0.10.0; bug with float types fixed in Hive 0.14.0, decimal type support added in Hive 0.14.0)

string

get_json_object(string json_string, string path)

Extracts json object from a json string based on json path specified, and returns json string of the extracted json object. It will return null if the input json string is invalid. NOTE: The json path can only have the characters [0-9a-z_], i.e., no upper-case or special characters. Also, the keys *cannot start with numbers.* This is due to restrictions on Hive column names.

boolean

in_file(string str, string filename)

Returns true if the string str appears as an entire line in filename.

int

instr(string str, string substr)

Returns the position of the first occurrence of substr in str. Returns null if either of the arguments are null and returns 0 if substr could not be found in str. Be aware that this is not zero based. The first character in str has index 1.

int

length(string A)

Returns the length of the string.

int

locate(string substr, string str[, int pos])

Returns the position of the first occurrence of substr in str after position pos.

string

lower(string A) lcase(string A)

Returns the string resulting from converting all characters of B to lower case. For example, lower('fOoBaR') results in 'foobar'.

string

lpad(string str, int len, string pad)

Returns str, left-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters. In case of empty pad string, the return value is null.

string

ltrim(string A)

Returns the string resulting from trimming spaces from the beginning(left hand side) of A. For example, ltrim(' foobar ') results in 'foobar '.

array<struct<string,double>>

ngrams(array<array<string>>, int N, int K, int pf)

Returns the top-k N-grams from a set of tokenized sentences, such as those returned by the sentences() UDAF. See StatisticsAndDataMining for more information.

intoctet_length(string str)Returns the number of octets required to hold the string str in UTF-8 encoding (since Hive 2.2.0). Note that octet_length(str) can be larger than character_length(str).

string

parse_url(string urlString, string partToExtract [, string keyToExtract])

Returns the specified part from the URL. Valid values for partToExtract include HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO. For example, parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'HOST') returns 'facebook.com'. Also a value of a particular key in QUERY can be extracted by providing the key as the third argument, for example, parse_url('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY', 'k1') returns 'v1'.

string

printf(String format, Obj... args)

Returns the input formatted according do printf-style format strings (as of Hive 0.9.0).

string

regexp_extract(string subject, string pattern, int index)

Returns the string extracted using the pattern. For example, regexp_extract('foothebar', 'foo(.*?)(bar)', 2) returns 'bar.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc. The 'index' parameter is the Java regex Matcher group() method index. See docs/api/java/util/regex/Matcher.html for more information on the 'index' or Java regex group() method.

string

regexp_replace(string INITIAL_STRING, string PATTERN, string REPLACEMENT)

Returns the string resulting from replacing all substrings in INITIAL_STRING that match the java regular expression syntax defined in PATTERN with instances of REPLACEMENT. For example, regexp_replace("foobar", "oo|ar", "") returns 'fb.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc.

string

repeat(string str, int n)

Repeats str n times.

stringreplace(string A, string OLD, string NEW)Returns the string A with all non-overlapping occurrences of OLD replaced with NEW (as of Hive 1.3.0 and 2.1.0). Example: select replace("ababab", "abab", "Z"); returns "Zab".

string

reverse(string A)

Returns the reversed string.

string

rpad(string str, int len, string pad)

Returns str, right-padded with pad to a length of len. If str is longer than len, the return value is shortened to len characters. In case of empty pad string, the return value is null.

string

rtrim(string A)

Returns the string resulting from trimming spaces from the end(right hand side) of A. For example, rtrim(' foobar ') results in ' foobar'.

array<array<string>>

sentences(string str, string lang, string locale)

Tokenizes a string of natural language text into words and sentences, where each sentence is broken at the appropriate sentence boundary and returned as an array of words. The 'lang' and 'locale' are optional arguments. For example, sentences('Hello there! How are you?') returns ( ("Hello", "there"), ("How", "are", "you") ).

string

space(int n)

Returns a string of n spaces.

array

split(string str, string pat)

Splits str around pat (pat is a regular expression).

map<string,string>

str_to_map(text[, delimiter1, delimiter2])

Splits text into key-value pairs using two delimiters. Delimiter1 separates text into K-V pairs, and Delimiter2 splits each K-V pair. Default delimiters are ',' for delimiter1 and '=:' for delimiter2.

string

substr(string|binary A, int start) substring(string|binary A, int start)

Returns the substring or slice of the byte array of A starting from start position till the end of string A. For example, substr('foobar', 4) results in 'bar' (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr]).

string

substr(string|binary A, int start, int len) substring(string|binary A, int start, int len)

Returns the substring or slice of the byte array of A starting from start position with length len. For example, substr('foobar', 4, 1) results in 'b' (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr]).

stringsubstring_index(string A, string delim, int count)Returns the substring from string A before count occurrences of the delimiter delim (as of Hive 1.3.0). If count is positive, everything to the left of the final delimiter (counting from the left) is returned. If count is negative, everything to the right of the final delimiter (counting from the right) is returned. Substring_index performs a case-sensitive match when searching for delim. Example: substring_index('www.apache.org', '.', 2) = 'www.apache'.

string

translate(string|char|varchar input, string|char|varchar from, string|char|varchar to)

Translates the input string by replacing the characters present in the from string with the corresponding characters in the to string. This is similar to the translate function in PostgreSQL. If any of the parameters to this UDF are NULL, the result is NULL as well. (Available as of Hive 0.10.0, for string types)

Char/varchar support added as of Hive 0.14.0.

string

trim(string A)

Returns the string resulting from trimming spaces from both ends of A. For example, trim(' foobar ') results in 'foobar'

binary

unbase64(string str)

Converts the argument from a base 64 string to BINARY. (As of Hive 0.12.0.)

string

upper(string A) ucase(string A)

Returns the string resulting from converting all characters of A to upper case. For example, upper('fOoBaR') results in 'FOOBAR'.

stringinitcap(string A)Returns string, with the first letter of each word in uppercase, all other letters in lowercase. Words are delimited by whitespace. (As of Hive 1.1.0.)
intlevenshtein(string A, string B)Returns the Levenshtein distance between two strings (as of Hive 1.2.0). For example, levenshtein('kitten', 'sitting') results in 3.
stringsoundex(string A)Returns soundex code of the string (as of Hive 1.2.0). For example, soundex('Miller') results in M460.

Data Masking Functions

The following built-in data masking functions are supported in Hive:

Return Type

Name(Signature)

Description

string

mask(string str[, string upper[, string lower[, string number]]])

Returns a masked version of str (as of Hive 2.1.0). By default, upper case letters are converted to "X", lower case letters are converted to "x" and numbers are converted to "n". For example mask("abcd-EFGH-8765-4321") results in xxxx-XXXX-nnnn-nnnn. You can override the characters used in the mask by supplying additional arguments: the second argument controls the mask character for upper case letters, the third argument for lower case letters and the fourth argument for numbers. For example, mask("abcd-EFGH-8765-4321", "U", "l", "#") results in llll-UUUU-####-####.

stringmask_first_n(string str[, int n])Returns a masked version of str with the first n values masked (as of Hive 2.1.0). Upper case letters are converted to "X", lower case letters are converted to "x" and numbers are converted to "n". For example, mask_first_n("1234-5678-8765-4321", 4) results in nnnn-5678-8765-4321.
stringmask_last_n(string str[, int n])Returns a masked version of str with the last n values masked (as of Hive 2.1.0). Upper case letters are converted to "X", lower case letters are converted to "x" and numbers are converted to "n". For example, mask_last_n("1234-5678-8765-4321", 4) results in 1234-5678-8765-nnnn.
stringmask_show_first_n(string str[, int n])Returns a masked version of str, showing the first n characters unmasked (as of Hive 2.1.0). Upper case letters are converted to "X", lower case letters are converted to "x" and numbers are converted to "n". For example, mask_show_first_n("1234-5678-8765-4321", 4) results in 1234-nnnn-nnnn-nnnn.
stringmask_show_last_n(string str[, int n])Returns a masked version of str, showing the last n characters unmasked (as of Hive 2.1.0). Upper case letters are converted to "X", lower case letters are converted to "x" and numbers are converted to "n". For example, mask_show_last_n("1234-5678-8765-4321", 4) results in nnnn-nnnn-nnnn-4321.
stringmask_hash(string|char|varchar str)Returns a hashed value based on str (as of Hive 2.1.0). The hash is consistent and can be used to join masked values together across tables. This function returns null for non-string types.

Misc. Functions

Return Type

Name(Signature)

Description

varies

java_method(class, method[, arg1[, arg2..]])

Synonym for reflect. (As of Hive 0.9.0.)

varies

reflect(class, method[, arg1[, arg2..]])

Calls a Java method by matching the argument signature, using reflection. (As of Hive 0.7.0.) See Reflect (Generic) UDF for examples.

int

hash(a1[, a2...])

Returns a hash value of the arguments. (As of Hive 0.4.)

stringcurrent_user()Returns current user name from the configured authenticator manager (as of Hive 1.2.0). Could be the same as the user provided when connecting, but with some authentication managers (for example HadoopDefaultAuthenticator) it could be different.
stringlogged_in_user()Returns current user name from the session state (as of Hive 2.2.0). This is the username provided when connecting to Hive.
stringcurrent_database()Returns current database name (as of Hive 0.13.0).
stringmd5(string/binary)Calculates an MD5 128-bit checksum for the string or binary (as of Hive 1.3.0). The value is returned as a string of 32 hex digits, or NULL if the argument was NULL. Example: md5('ABC') = '902fbdd2b1df0c4f70b4a5d23525e932'.
string

sha1(string/binary)

sha(string/binary)

Calculates the SHA-1 digest for string or binary and returns the value as a hex string (as of Hive 1.3.0). Example: sha1('ABC') = '3c01bdbb26f358bab27f267924aa2c9a03fcfdb8'.
bigintcrc32(string/binary)Computes a cyclic redundancy check value for string or binary argument and returns bigint value (as of Hive 1.3.0). Example: crc32('ABC') = 2743272264.
stringsha2(string/binary, int)Calculates the SHA-2 family of hash functions (SHA-224, SHA-256, SHA-384, and SHA-512) (as of Hive 1.3.0). The first argument is the string or binary to be hashed. The second argument indicates the desired bit length of the result, which must have a value of 224, 256, 384, 512, or 0 (which is equivalent to 256). SHA-224 is supported starting from Java 8. If either argument is NULL or the hash length is not one of the permitted values, the return value is NULL. Example: sha2('ABC', 256) = 'b5d4045c3f466fa91fe2cc6abe79232a1a57cdf104f7a26e716e0a1e2789df78'.
binaryaes_encrypt(input string/binary, key string/binary)Encrypt input using AES (as of Hive 1.3.0). Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL. Example: base64(aes_encrypt('ABC', '1234567890123456')) = 'y6Ss+zCYObpCbgfWfyNWTw=='.
binaryaes_decrypt(input binary, key string/binary)Decrypt input using AES (as of Hive 1.3.0). Key lengths of 128, 192 or 256 bits can be used. 192 and 256 bits keys can be used if Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files are installed. If either argument is NULL or the key length is not one of the permitted values, the return value is NULL. Example: aes_decrypt(unbase64('y6Ss+zCYObpCbgfWfyNWTw=='), '1234567890123456') = 'ABC'.
stringversion()Returns the Hive version (as of Hive 2.1.0). The string contains 2 fields, the first being a build number and the second being a build hash. Example: "select version();" might return "2.1.0.2.5.0.0-1245 r027527b9c5ce1a3d7d0b6d2e6de2378fb0c39232". Actual results will depend on your build.

xpath

The following functions are described in LanguageManual XPathUDF:

...

Return Type

Name(Signature)

Description

BIGINT

count(*), count(expr), count(DISTINCT expr[, expr...])

count(*) - Returns the total number of retrieved rows, including rows containing NULL values.

count(expr) - Returns the number of rows for which the supplied expression is non-NULL.

count(DISTINCT expr[, expr]) - Returns the number of rows for which the supplied expression(s) are unique and non-NULL. Execution of this can be optimized with hive.optimize.distinct.rewrite.

DOUBLE

sum(col), sum(DISTINCT col)

Returns the sum of the elements in the group or the sum of the distinct values of the column in the group.

DOUBLE

avg(col), avg(DISTINCT col)

Returns the average of the elements in the group or the average of the distinct values of the column in the group.

DOUBLE

min(col)

Returns the minimum of the column in the group.

DOUBLE

max(col)

Returns the maximum value of the column in the group.

DOUBLE

variance(col), var_pop(col)

Returns the variance of a numeric column in the group.

DOUBLE

var_samp(col)

Returns the unbiased sample variance of a numeric column in the group.

DOUBLE

stddev_pop(col)

Returns the standard deviation of a numeric column in the group.

DOUBLE

stddev_samp(col)

Returns the unbiased sample standard deviation of a numeric column in the group.

DOUBLE

covar_pop(col1, col2)

Returns the population covariance of a pair of numeric columns in the group.

DOUBLE

covar_samp(col1, col2)

Returns the sample covariance of a pair of a numeric columns in the group.

DOUBLE

corr(col1, col2)

Returns the Pearson coefficient of correlation of a pair of a numeric columns in the group.

DOUBLE

percentile(BIGINT col, p)

Returns the exact pth percentile of a column in the group (does not work with floating point types). p must be between 0 and 1. NOTE: A true percentile can only be computed for integer values. Use PERCENTILE_APPROX if your input is non-integral.

array<double>

percentile(BIGINT col, array(p1 [, p2]...))

Returns the exact percentiles p1, p2, ... of a column in the group (does not work with floating point types). pi must be between 0 and 1. NOTE: A true percentile can only be computed for integer values. Use PERCENTILE_APPROX if your input is non-integral.

DOUBLE

percentile_approx(DOUBLE col, p [, B])

Returns an approximate pth percentile of a numeric column (including floating point types) in the group. The B parameter controls approximation accuracy at the cost of memory. Higher values yield better approximations, and the default is 10,000. When the number of distinct values in col is smaller than B, this gives an exact percentile value.

array<double>

percentile_approx(DOUBLE col, array(p1 [, p2]...) [, B])

Same as above, but accepts and returns an array of percentile values instead of a single one.

double

regr_avgx(independent, dependent)

Equivalent to avg(dependent). As of Hive 2.2.0.

double

regr_avgy(independent, dependent)

Equivalent to avg(independent). As of Hive 2.2.0.

double

regr_count(independent, dependent)

Returns the number of non-null pairs used to fit the linear regression line. As of Hive 2.2.0.

double

regr_intercept(independent, dependent)

Returns the y-intercept of the linear regression line, i.e. the value of b in the equation dependent = a * independent + b. As of Hive 2.2.0.

double

regr_r2(independent, dependent)

Returns the coefficient of determination for the regression. As of Hive 2.2.0.

double

regr_slope(independent, dependent)

Returns the slope of the linear regression line, i.e. the value of a in the equation dependent = a * independent + b. As of Hive 2.2.0.

double

regr_sxx(independent, dependent)

Equivalent to regr_count(independent, dependent) * var_pop(dependent). As of Hive 2.2.0.

double

regr_sxy(independent, dependent)

Equivalent to regr_count(independent, dependent) * covar_pop(independent, dependent). As of Hive 2.2.0.

doubleregr_syy(independent, dependent)

Equivalent to regr_count(independent, dependent) * var_pop(independent). As of Hive 2.2.0.

array<struct {'x','y'}>

histogram_numeric(col, b)

Computes a histogram of a numeric column in the group using b non-uniformly spaced bins. The output is an array of size b of double-valued (x,y) coordinates that represent the bin centers and heights

array

collect_set(col)

Returns a set of objects with duplicate elements eliminated.

array

collect_list(col)

Returns a list of objects with duplicates. (As of Hive 0.13.0.)

INTEGERntile(INTEGER x)

Divides an ordered partition into x groups called buckets and assigns a bucket number to each row in the partition. This allows easy calculation of tertiles, quartiles, deciles, percentiles and other common summary statistics. (As of Hive 0.11.0.)

...

Normal user-defined functions, such as concat(), take in a single input row and output a single output row. In contrast, table-generating functions transform a single input row to multiple output rows.

Takes a set of names (keys) and a JSON string

Return TypeRow-set columns types

Name(Signature)

Description

N rowsT

explode(ARRAYARRAY<T> a)

Explodes an array to multiple rows. Returns a row-set with a single column (col), one row for each element from the array.N rows

Tkey,Tvalue

explode(MAPMAP<Tkey,Tvalue> m)

Explodes a map to multiple rows. Returns a row-set with a two columns (key,value) , one row for each key-value pair from the input map with two columns in each row: one for the key and another for the value. (As of Hive 0.8.0.).

 

inline(ARRAY<STRUCT[,STRUCT]>int,Tposexplode(ARRAY<T> a)Explodes an array to multiple rows with additional positional column of int type (position of items in the original array, starting with 0). Returns a row-set with two columns (pos,val), one row for each element from the array.

T1,...,Tn

inline(ARRAY<STRUCT<f1:T1,...,fn:Tn>> a)

Explodes an array of structs into a tableto multiple rows. Returns a row-set with N columns (N = number of top level elements in the struct), one row per struct from the array. (As of Hive 0.10.)

Array Type

explode(array<TYPE> a)

For each element in a, generates a row containing that element.

tuple

json_tuple(jsonStr, k1, k2, ...)

T1,...,Tn/rstack(int r,T1 V1,...,Tn/r Vn)Breaks up n values V1,...,Vn into r rows. Each row will have n/r columns. r must be constant.
   

string1,...,stringn

json_tuple(string jsonStr,string k1,...,string kn)

Takes JSON string and a set of n keys, and returns a tuple of n values. This is a more efficient version of the get_json_object UDF because it can get multiple keys with just one call.tuple

string 1,...,stringn

parse_url_tuple(url, p1, p2, string urlStr,string p1,...,string pn)

Takes URL string and a set of n URL parts, and returns a tuple of n values. This is similar to the parse_url() UDF but can extract multiple parts at once out of a URL. Valid part names are: HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, USERINFO, QUERY:<KEY>.

N rows

posexplode(ARRAY)

Behaves like explode for arrays, but includes the position of items in the original array by returning a tuple of (pos, value). (As of Hive 0.13.0.)

N rows

stack(INT n, v_1, v_2, ..., v_k)

Breaks up v_1, ..., v_k into n rows. Each row will have k/n columns. n must be constant.

 

Usage Examples

explode (array)

Code Block
languagesql
select explode(array('A','B','C'));
select explode(array('A','B','C')) as col;
select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf;
select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf as col;

HTML
outputxhtml
<table><tbody><tr><th>col</th></tr><tr><td>A</td></tr><tr><td>B</td></tr><tr><td>C</td></tr></tbody></table>



explode (map)

 

Code Block
languagesql
select explode(map('A',10,'B',20,'C',30));
select explode(map('A',10,'B',20,'C',30)) as (key,value);
select tf.* from (select 0) t lateral view explode(map('A',10,'B',20,'C',30)) tf;
select tf.* from (select 0) t lateral view explode(map('A',10,'B',20,'C',30)) tf as key,value;

HTML
outputxhtml
<table><tbody><tr><th>key</th><th>value</th></tr><tr><td>A</td><td>10</td></tr><tr><td>B</td><td>20</td></tr><tr><td>C</td><td>30</td></tr></tbody></table>
 

 

posexplode (array)

 

Code Block
languagesql
select posexplode(array('A','B','C'));
select posexplode(array('A','B','C')) as (pos,val);
select tf.* from (select 0) t lateral view posexplode(array('A','B','C')) tf;
select tf.* from (select 0) t lateral view posexplode(array('A','B','C')) tf as pos,val;

HTML
outputxhtml
<table><tbody><tr><th>pos</th><th>val</th></tr><tr><td>0</td><td>A</td></tr><tr><td>1</td><td>B</td></tr><tr><td>2</td><td>C</td></tr></tbody></table>
 

 

inline (array of structs)

Code Block
languagesql
select inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02')));
select inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) as (col1,col2,col3);
select tf.* from (select 0) t lateral view inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) tf;
select tf.* from (select 0) t lateral view inline(array(struct('A',10,date '2015-01-01'),struct('B',20,date '2016-02-02'))) tf as col1,col2,col3;

HTML
outputxhtml
<table><tbody><tr><th>col1</th><th>col2</th><th>col3</th></tr><tr><td>A</td><td>10</td><td>2015-01-01</td></tr><tr><td>B</td><td>20</td><td>2016-02-02</td></tr></tbody></table>


stack (values)

 

Code Block
languagesql
select stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01');
select stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') as (col0,col1,col2);
select tf.* from (select 0) t lateral view stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') tf;
select tf.* from (select 0) t lateral view stack(2,'A',10,date '2015-01-01','B',20,date '2016-01-01') tf as col0,col1,col2;

HTML
outputxhtml
<table><tbody><tr><th>col0</th><th>col1</th><th>col2</th></tr><tr><td>A</td><td>10</td><td>2015-01-01</td></tr><tr><td>B</td><td>20</td><td>2016-01-01</td></tr></tbody></table>
 

 

 

Using the syntax "SELECT udtf(col) AS colAlias..." has a few limitations:

...

For information about how to create a custom UDF, see Hive Plugins and Create Function.

 

Save

Save

Save

select explode(array('A','B','C'));select explode(array('A','B','C')) as col;select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf;select tf.* from (select 0) t lateral view explode(array('A','B','C')) tf as col;