DIFFERENCE

The DIFFERENCE function returns a value from 0 to 4 representing the difference between the sounds of two strings based on applying the SOUNDEX function to the strings. A value of 4 is the best possible sound match.

expression-1: An expression that returns a built-in numeric, character-string, or graphic-string data types, but not CLOBs or DBCLOBs. The arguments cannot be binary strings. A numeric argument is cast to a character string before evaluating the function. For more information about converting numeric to a character string, see VARCHAR.
expression-2: An expression that returns a built-in numeric, character-string, or graphic-string data types, but not CLOBs or DBCLOBs. The arguments cannot be binary strings. A numeric argument is cast to a character string before evaluating the function. For more information about converting numeric to a character string, see VARCHAR.

The data type of the result is INTEGER. If either argument can be null, the result can be null; if either argument is null, the result is the null value.

Examples

Assume the following statement:

  SELECT DIFFERENCE('CONSTRAINT','CONSTANT'),
         SOUNDEX('CONSTRAINT'),
         SOUNDEX('CONSTANT')
    FROM SYSIBM.SYSDUMMY1

Returns 4, C523, and C523. Since the two strings return the same SOUNDEX value, the difference is 4 (the highest value possible).

Assume the following statement:

  SELECT DIFFERENCE('CONSTRAINT','CONTRITE'),
         SOUNDEX('CONSTRAINT'),
         SOUNDEX('CONTRITE')
    FROM SYSIBM.SYSDUMMY1

Returns 2, C523, and C536. In this case, the two strings return different SOUNDEX values, and hence, a lower difference value.