DECODE

Purpose

The decode function returns the result value for which the expression, expr, matches the expression, search. If no match is found, NULL or − if specified − the default value is returned.

Usage Notes

• Decode is similar to CASE, but has slightly different functionality (to be compliant to other databases):
  • The expression expr can be directly compared with value NULL . For example, DECODE(my_column, NULL, 0, my_column)).
  • String comparisons are done "non-padded". For example, DECODE(my_column, 'abc', TRUE, FALSE) on a CHAR(10) column always returns false.
• Due to readability reasons we recommend to use CASE.

Example

SELECT DECODE('abc', 'xyz', 1, 'abc', 2, 3);

Result

The result is 2.