Type Conversion Functionsedit

Functions for converting an expression of one data type to another.

CASTedit

Synopsis. 

CAST ( expression AS data_type )

Expression to cast

Target data type to cast to

Description. Casts the result of the given expression to the target data type. If the cast is not possible (for example because of target type is too narrow or because the value itself cannot be converted), the query fails.

SELECT CAST('123' AS INT) AS int;

      int
---------------
123
SELECT CAST(123 AS VARCHAR) AS string;

    string
---------------
123
SELECT YEAR(CAST('2018-05-19T11:23:45Z' AS TIMESTAMP)) AS year;

     year
---------------
2018

CONVERTedit

Synopsis. 

CONVERT ( expression, data_type )

Expression to convert

Target data type to convert to

Description. Works exactly like CAST with slightly different syntax. Moreover, apart from the standard data types it supports the corresponding ODBC data types.

SELECT CONVERT('123', SQL_INTEGER) AS int;

      int
---------------
123
SELECT CONVERT('123', INTEGER) AS int;

      int
---------------
123