CAST is used to convert one data type to another data type. The most common data types are:

Character String Data:
     CHAR(length)
     VARCHAR(length)
     LONG VARCHAR(length)
     NATIONAL CHARACTER
     Character Large OBject (CLOB)
     NCLOB

Boolean Data

Binary Large OBject (BLOB) Data:
     GRAPHIC(length)
     VARGRAPHIC(length)
     LONG VARGRAPHIC(length)

Exact Numeric Data:
     SMALLINT
     INTEGER
     BIGINT
     DECIMAL(total,fraction) or NUMERIC

Approximate Numeric Data:
     FLOAT(precisionbits)
     REAL
     DOUBLE PRECISION

Date/Time/Timestamp Data:
     DATE
     TIME
     TIME WITH TIME ZONE
     TIMESTAMP

Intervals:
     Year-month
     Day-time

The data you are converting must be compatible with the new data type. Here are some possible conversions:

> Any character type to any other type such as date, time, or numeric.
> Any type to any character type.
> Any numeric type to any other numeric type.
> Any numeric type to an interval such as INTERVAL DAY, or INTERVAL MINUTE.
> Any DATE to a TIMESTAMP where the time portion will be zero.
> Any TIME to a TIME with fractional seconds, or a TIMESTAMP where the date is the current date.
> Any TIMESTAMP to a DATE, TIME, or TIMESTAMP with different fractional seconds.
> Any year-month INTERVAL to another year-month INTERVAL with different leading precision.
> Any day-time INTERVAL to another day-time INTERVAL with different leading precision.
> DB2, MySQL, PostgreSQL, and Sybase support CAST.