ASA SQL Reference
SQL Data Types
Type conversions can happen automatically, or they can be explicitly requested using the CAST or CONVERT function.
If a string is used in a numeric expression or as an argument to a function that expects a numeric argument, the string is converted to a number.
If a number is used in a string expression or as a string function argument, it is converted to a string before being used.
All date constants are specified as strings. The string is automatically converted to a date before use.
There are certain cases where the automatic database conversions are not appropriate.
'12/31/90' + 5 'a' > 0
The automatic data type conversion fails here. You can use the CAST or CONVERT function to force type conversions. For information about the CAST and CONVERT functions, see Data type conversion functions.
The following functions can also be used to force type conversions (see SQL Functions).
DATE( value ) Converts the expression into a date, and removes any hours, minutes or seconds. Conversion errors may be reported.
STRING( value ) Equivalent to CAST( value AS LONG VARCHAR ).
For more information about the STRING function, see STRING function [String].
VALUE+0.0 Equivalent to CAST( value AS DECIMAL ).
For more information about the CAST function, see CAST function [Data type conversion].
Conversion when using comparison operators