Although the FORMAT phrase cannot be used to change the underlying data type defined for a column, the phrase may be used to change the display for a numeric value.
For example, if the field values for columns Wholesale and Retail, both defined as DECIMAL(7,2), are 12467.75 and 21500.50, respectively, the result of the expression:
CAST (Wholesale - Retail AS FORMAT '-99999')
A FORMAT phrase does not affect data that is returned to the client system in Record Mode (client system internal format).
In the previous example, the value returned to the client system is still in packed decimal format (for example, -9032.75).
The use of FORMAT in CAST is a Teradata extension to the ANSI standard.