Category: ASE: Functions: Datatype Conversion Functions

cast()

The Datatype Conversion Function cast() converts a given value of a datatype into another datatype. The function cast() can also change the nullability of the parameter "expression". Furthermore, cast() returns the default format for a given date and time value. The function cast() is available in ASE® starting with version 12.5.

Syntax of the Datatype Conversion Function cast()

    cast(expression as datatype [(length | precision[, scale])])
    

Parameters of the Datatype Conversion Function cast()

expression
The parameter "expression" contains the value of an arbitrary datatype to be converted. The parameter should be set between double quotes. It can contain column names, constants, Functions as well as any combination of constants and functions which can be linked with arithmetic or bitwise operators or subqueries.

If Java is active in the current Datenbank the parameter "expression" can be converted into a Java-SQL class.

When converting a datatype into unichar the default length is 30, if the parameter "length" has not been given.

length
The parameter "length" is an optional placeholder for a datatype specific length. If the datatype can take a length option, this can be added in parentheses, e.g. varchar(255). The parameter can be used with the datatypes char, nchar, unichar, univarchar, varchar, nvarchar, binary and varbinary . If length is not given, all characters or bytes after the 30th will be ignored and cut off without warning. The maximum length for characters and bytes is 64K.

precision
The parameter "precision" is equal to the number of digits for the datatypes numeric or decimal. For the datatype float the parameter "precision" describes the number of binary digits in its mantissa, i.e. the number of logarithms behind the decimal point. If the parameter "precision" has not been given a value, ASE will use the default precision of 18 for numeric and decimal datatypes.

scale
The parameter "scale" describes the number of digits on the right side of the decimal point of a decimal value. The parameter "scale" is optional. If it is not set the default value of "0" is used.

Example for the Datatype Conversion Function cast()

    select cast( as datetime)

    go

    -----

    
    

Returns the date in default format.

See also:

ASE T-SQL - Aggregate Functions,
biginttohex(),
bintostr(),
convert(),
Datatype Conversion Functions,
explicit conversion,
hextobigint(),
hextoint(),
implicit conversions,
inttohex().