The Impala Query Language and Built-in Functions - Learning Cloudera Impala - page 60

Here is how Casting works with the INT data type:
Impala automatically converts the INT data type to a larger integer data type
( BIGINT ) or a floating-point data type ( FLOAT or DOUBLE ).
You can use the CAST() operator to convert INT to TINYINT , SMALLINT ,
STRING , or TIMESTAMP .
You can also cast an INT value to TIMESTAMP . While using Cast() with
INT N to TIMESTAMP , the resulting value shows N seconds past the start of
the epoch date (January 1, 1970).
• BIGINT : In Impala, BIGINT represents an 8-byte integer type of data when
used with the CREATE TABLE or ALTER TABLE statement. The value
of BIGINT in Impala ranges between -9223372036854775808 and
9223372036854775807, and there is no UNSIGNED subtype with BIGINT .
Here is how Casting works with the BIGINT data type:
Impala automatically converts BIGINT to a floating-point type ( FLOAT or
DOUBLE ).
Using the CAST() operator, BIGINT is converted to TINYINT , SMALLINT ,
INT , STRING , or TIMESTAMP .
Conversion of BIGINT to TIMESTAMP also works as INT . While using
Cast() with BIGINT N to TIMESTAMP , the resulting value shows N seconds
past the start of the epoch date (January 1, 1970).
• SMALLINT : In Impala, SMALLINT represents a 2-byte integer type of data
when used with the CREATE TABLE or ALTER TABLE statements. The value
of SMALLINT in Impala ranges between -32768 and 32767, and there is no
UNSIGNED subtype with SMALLINT .
Here is how Casting works with the SMALLINT data type:
Impala automatically converts SMALLINT to a larger integer date type ( INT
or BIGINT ) or a floating-point type ( FLOAT or DOUBLE ).