CAST

Description

The CAST() function converts a value (of any type) into the specified datatype.

Syntax

  1. > CAST(value AS datatype)

Parameter Values

ParameterDescription
valueRequired. The value to convert
datatypeRequired. The datatype to convert to

Currently, cast can support following conversion: * Conversion between numeric types, mainly including SIGNED, UNSIGNED, FLOAT, and DOUBLE type. * Numeric types to character CHAR type. * Numeric character types to numerical types(negative into SIGNED).

Examples

  1. > drop table if exists t1;
  2. > CREATE TABLE t1 (a int,b float,c char(1),d varchar(15));
  3. > INSERT INTO t1 VALUES (1,1.5,'1','-2');
  4. > SELECT CAST(a AS FLOAT) a_cast,CAST(b AS UNSIGNED) b_cast,CAST(c AS SIGNED) c_cast, CAST(d AS SIGNED) d_cast from t1;
  5. +--------+--------+--------+--------+
  6. | a_cast | b_cast | c_cast | d_cast |
  7. +--------+--------+--------+--------+
  8. | 1.0000 | 1 | 1 | -2 |
  9. +--------+--------+--------+--------+
  10. > SELECT CAST(a AS CHAR) a_cast, CAST(b AS CHAR) b_cast,CAST(c AS DOUBLE) c_cast, CAST(d AS FLOAT) d_cast from t1;
  11. +--------+--------+--------+---------+
  12. | a_cast | b_cast | c_cast | d_cast |
  13. +--------+--------+--------+---------+
  14. | 1 | 1.5 | 1.0000 | -2.0000 |
  15. +--------+--------+--------+---------+

Constraints

Currently, MatrixOne doesn’t support select function() without from tables.

  • Non-numeric character types cannot be converted to numeric types.
  • Numeric and character types with formats of Data cannot be converted to Date.
  • Date and Datetime types cannot be converted to character types.
  • Date and Datetime cannot be converted to each other.