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- Type
Primitive Type
Number
DOUBLE
FLOAT
BIGINT
INT
INT TINYINT
SMALLINT
FLOAT
TINYINT
STRING
BOOLEAN
This type hierarchy defines how the types are implicitly converted in the query language. Implicit conversion is allowed for types from child to an ancestor. So when a query expression expects type1 and the data is of type2, type2 is implicitly converted to type1 if type1 is an ancestor of type2 in the type hierarchy. Apart from these fundamental rules for implicit conversion based on type system, Hive also allows the special case for conversion:
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Note that the type hierarchy allows the implicit conversion of STRING to DOUBLE.
Explicit type conversion can be done using the cast operator as shown in the #Built in functions section below.
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Operator | Operand types | Description | ||
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<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="bc0001f78009f03a-bf67ca94-48f44f62-a726966d-6eb4b2e0b4496ebd7a575205"><ac:plain-text-body><![CDATA[ | 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. if A is an array comprising of ['foo', 'bar'] then A[0] returns 'foo' and A[1] returns 'bar' | ]]></ac:plain-text-body></ac:structured-macro> |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="d05123e4739602cb-d5eea86c-40554065-ab7984c5-d1c027bd90b46b09b438886d"><ac:plain-text-body><![CDATA[ | 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. if M is a map comprising of {'f' -> 'foo', 'b' -> 'bar', 'all' -> 'foobar'} then M['all'] returns 'foobar' | ]]></ac:plain-text-body></ac:structured-macro> |
S.x | S is a struct | returns the x field of S e.g for struct foobar {int foo, int bar} foobar.foo returns the integer stored in the foo field of the struct. |
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Return Type | Aggregation Function Name (Signature) | Description | ||
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<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="161dd1ac9ce1d77f-1bd9af9f-4e444d46-89fab736-d2367c9af358590ca28315e8"><ac:plain-text-body><![CDATA[ | 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. | ]]></ac:plain-text-body></ac:structured-macro> |
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 value of the column in the group | ||
DOUBLE | max(col) | returns the maximum value of the column in the group |
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