...
Operator | Operand types | Description |
---|---|---|
A = B | All primitive types | TRUE if expression A is equal to expression B otherwise FALSE. |
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 As of version 0.9.0.) |
A == B | None! | Fails because of invalid syntax. SQL uses =, not ==. |
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 | a synonym 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 As of version 0.9.0.) |
A IS NULL | all 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 [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) e. g. For example, 'foobar' like 'foo' evaluates to FALSE where as 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. E.g. For example, 'foobar' RLIKE 'foo' evaluates to TRUE and so does 'foobar' RLIKE '^f.*r$'. |
A REGEXP B | strings | Same as RLIKE. |
Arithmetic Operators
The following operators support various common arithmetic operations on the operands. All return number types; if any of the operands are NULL, then the result is also NULL.
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. e.g. 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 B from A. The result is a double type. |
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. |
...
Constructor Function | Operands | Description |
---|---|---|
map | (key1, value1, key2, value2, ...) | Creates a map with the given key/value pairs. |
struct | (val1, val2, val3, ...) | Creates a struct with the given field values. Struct field names will be col1, col2, .... |
named_struct | (name1, val1, name2, val2, ...) | Creates a struct with the given field names and values. (as As of Hive 0.8.0.) |
array | (val1, val2, ...) | Creates an array with the given elements. |
create_union | (tag, val1, val2, ...) | Creates a union type with the value that is being pointed to by the tag parameter. |
Operators on Complex Types
...
Operator | Operand types | Description |
---|---|---|
A[n] | A is an Array and n is an int | Returns the nth element in the array A. The first element has index 0 e. g. For example, if A is an array comprising of ['foo', 'bar'] then A[0] returns 'foo' and A[1] returns 'bar'. |
M[key] | M is a Map<K, V> and key has type K | Returns the value corresponding to the key in the map e. g. For example, if M is a map comprising of {'f' -> 'foo', 'b' -> 'bar', 'all' -> 'foobar'} then M['all'] returns 'foobar'. |
S.x | S is a struct | Returns the x field of S. e.g For example for the struct foobar {int foo, int bar}, foobar.foo returns the integer stored in the foo field of the struct. |
...
Return Type | Name (Signature) | Description |
---|---|---|
DOUBLE | round(DOUBLE a) | Returns the rounded |
DOUBLE | round(DOUBLE a, INT d) | Returns |
BIGINT | floor(DOUBLE a) | Returns the maximum |
BIGINT | ceil(DOUBLE a), ceiling(DOUBLE a) | Returns the minimum BIGINT value that is equal to or greater than |
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 |
DOUBLE | ln(DOUBLE a), ln(DECIMAL a) | Returns the natural logarithm of the argument |
DOUBLE | log10(DOUBLE a), log10(DECIMAL a) | Returns the base-10 logarithm of the argument |
DOUBLE | log2(DOUBLE a), log2(DECIMAL a) | Returns the base-2 logarithm of the argument |
DOUBLE | log(DOUBLE base, DOUBLE a) log(DECIMAL base, DECIMAL a) | Return Returns the base- |
DOUBLE | pow(DOUBLE a, DOUBLE p), power(DOUBLE a, DOUBLE p) | Return Returns |
DOUBLE | sqrt(DOUBLE a), sqrt(DECIMAL a) | Returns the square root of |
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 |
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. ( |
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 |
DOUBLE | sin(DOUBLE a), sin(DECIMAL a) | Returns the sine of |
DOUBLE | asin(DOUBLE a), asin(DECIMAL a) | Returns the arc sin of |
DOUBLE | cos(DOUBLE a), cos(DECIMAL a) | Returns the cosine of |
DOUBLE | acos(DOUBLE a), acos(DECIMAL a) | Returns the arccosine of |
DOUBLE | tan(DOUBLE a), tan(DECIMAL a) | Returns the tangent of |
DOUBLE | atan(DOUBLE a), atan(DECIMAL a) | Returns the arctangent of |
DOUBLE | degrees(DOUBLE a), degrees(DECIMAL a) | Converts value of |
DOUBLE | radians(DOUBLE a), radians(DOUBLE a) | Converts value of |
INT or DOUBLE | positive(INT a), positive(DOUBLE a) | Returns |
INT or DOUBLE | negative(INT a), negative(DOUBLE a) | Returns |
DOUBLE or INT | sign(DOUBLE a), sign(DECIMAL a) | Returns the sign of |
DOUBLE | e() | Returns the value of e. |
DOUBLE | pi() | Returns the value of pi. |
Mathematical Functions and Operators for Decimal Datatypes
...
Return Type | Name(Signature) | Description |
---|---|---|
int | size(Map<K.V>) | Returns the number of elements in the map type. |
int | size(Array<T>) | Returns the number of elements in the array type. |
array<K> | map_keys(Map<K.V>) | Returns an unordered array containing the keys of the input map. |
array<V> | map_values(Map<K.V>) | Returns an unordered array containing the values of the input map. |
boolean | array_contains(Array<T>, value) | Returns TRUE if the array contains value. |
array<t> | sort_array(Array<T>) | Sorts the input array in ascending order according to the natural ordering of the array elements and returns it (as of version 0.9.0). |
Type Conversion Functions
...
Return Type | Name(Signature) | Description |
---|---|---|
binary | binary(string|binary) | Casts the parameter into a binary. |
Expected "=" to follow "type" | cast(expr as <type>) | Converts the results of the expression expr to <type> e. g. For example, cast('1' as BIGINT) will convert the string '1' to it its integral representation. A null is returned if the conversion does not succeed. |
...
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. |
bigint | unix_timestamp(string date) | Converts time string in format |
bigint | unix_timestamp(string date, string pattern) | Convert time string with given pattern (see [http://java.sun.com/j2se/1.4.2/docs/api/java/text/SimpleDateFormat.html]) to Unix time stamp (in seconds), return 0 if fail: unix_timestamp('2009-03-20', 'yyyy-MM-dd') = 1237532400. |
string | to_date(string timestamp) | Returns the date part of a timestamp string: to_date("1970-01-01 00:00:00") = "1970-01-01". |
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 | 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) | Return 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) | Return Returns the week number of a timestamp string: weekofyear("1970-11-01 00:00:00") = 44, weekofyear("1970-11-01") = 44. |
int | datediff(string enddate, string startdate) | Return Returns the number of days from startdate to enddate: datediff('2009-03-01', '2009-02-27') = 2. |
string | date_add(string startdate, int days) | Add Adds a number of days to startdate: date_add('2008-12-31', 1) = '2009-01-01'. |
string | date_sub(string startdate, int days) | Subtract Subtracts a number of days to startdate: date_sub('2008-12-31', 1) = '2008-12-30'. |
timestamp | from_utc_timestamp(timestamp, string timezone) | Assumes given timestamp is UTC and converts to given timezone (as of Hive 0.8.0). |
timestamp | to_utc_timestamp(timestamp, string timezone) | Assumes given timestamp is in given timezone and converts to UTC (as of Hive 0.8.0). |
Conditional Functions
Return Type | Name(Signature) | Description |
---|---|---|
T | if(boolean testCondition, T valueTrue, T valueFalseOrNull) | Return Returns valueTrue when testCondition is true, returns valueFalseOrNull otherwise. |
T | COALESCE(T v1, T v2, ...) | Return 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, return returns e; else return returns f. |
T | CASE WHEN a THEN b [WHEN c THEN d]* [ELSE e] END | When a = true, returns b; when c = true, return returns d; else return returns e. |
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) | Convert Converts the argument from binary to a base 64 string (as of Hive 0.12.0). |
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. e.g. 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) | Decode 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 As of Hive 0.12.0.) |
binary | encode(string src, string charset) | Encode 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 As of Hive 0.12.0.) |
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. e.g. 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 As of Hive 0.10.0; bug with float types fixed in Hive 0.14.0.) |
string | get_json_object(string json_string, string path) | Extract Extracts json object from a json string based on json path specified, and return 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 |
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 e. g. 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. |
string | ltrim(string A) | Returns the string resulting from trimming spaces from the beginning(left hand side) of A e. g. 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. |
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. e.g. 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, e.g. 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. e.g. 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; ' |
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, e.g. . 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; ' |
string | repeat(string str, int n) | Repeat Repeats str n times. |
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. |
string | rtrim(string A) | Returns the string resulting from trimming spaces from the end(right hand side) of A e. g. 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. e.g. For example, sentences('Hello there! How are you?') returns ( ("Hello", "there"), ("How", "are", "you") ). |
string | space(int n) | Return Returns a string of n spaces. |
array | split(string str, string pat) | Split 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 e. g. 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 e. g. For example, substr('foobar', 4, 1) results in 'b' (see [http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr]). |
string | translate(string input, string from, string to) | Translates the input string by replacing the characters present in the |
string | trim(string A) | Returns the string resulting from trimming spaces from both ends of A e. g. For example, trim(' foobar ') results in 'foobar' |
binary | unbase64(string str) | Convert Converts the argument from a base 64 string to BINARY. (as 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 e. g. For example, upper('fOoBaR') results in 'FOOBAR'. |
Misc. Functions
Return Type | Name(Signature) | Description |
---|---|---|
varies | java_method(class, method[, arg1[, arg2..]]) | Synonym for |
varies | reflect(class, method[, arg1[, arg2..]]) | Use this UDF to call Java methods Calls a Java method by matching the argument signature (uses , 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 As of Hive 0.4.) |
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. |
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. |
array<struct { | 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 As of Hive 0.13.0.) |
INTEGER | ntile(INTEGER x) | This function divides Divides an ordered partition into |
...
Return Type | Name(Signature) | Description |
---|---|---|
N rows | explode(ARRAY) | Returns one row for each element from the array. |
N rows | explode(MAP) | Returns 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 As of Hive 0.8.0.) |
| inline(ARRAY<STRUCT[,STRUCT]>) | Explodes an array of structs into a table. (as As of Hive 0.10.) |
Array Type | explode(array<TYPE> a) | For each element in a, explode() generates a row containing that element. |
tuple | json_tuple(jsonStr, k1, k2, ...) | It takes Takes a set of names (keys) and a JSON string, and returns a tuple of values. This is a more efficient version of the |
tuple | parse_url_tuple(url, p1, p2, ...) | This is similar to the |
N rows | posexplode(ARRAY) | Behaves like |
| 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. |
...
The parse_url_tuple() UDTF is similar to parse_url(), but can extract multiple parts of a given URL, returning the data in a tuple. Values for a particular key in QUERY can be extracted by appending a colon and the key to the partToExtract argument, e.g. parse, for example, parse_url_tuple('http://facebook.com/path1/p.php?k1=v1&k2=v2#Ref1', 'QUERY:k1', 'QUERY:k2') returns a tuple with values of 'v1','v2'. This is more efficient than calling parse_url() multiple times. All the input parameters and output column types are string.
...
would evaluate the length of each of the string_col's values in the map portion of the job. The side effect of the UDF being evaluated on the map-side is that you can't control the order of rows which get sent to the mapper. It is the same order in which the file split sent to the mapper gets deserialized. Any reduce side operation (e.g. SORT such as SORT BY, ORDER BY, regular JOIN, etc.) would apply to the UDFs output as if it is just another column of the table. This is fine since the context of the UDF's evaluate method is meant to be one row at a time.
...