SOUNDEX function [String]

Returns a number representing the sound of a string.

SOUNDEX ( string-expression )

The following statement returns two numbers, representing the sound of each name. The SOUNDEX value for each argument is 3827.

SELECT SOUNDEX( 'Smith' ), SOUNDEX( 'Smythe' ) FROM iq_dummy

SOUNDEX ( 'Smith' ) is equal to SOUNDEX ( 'Smythe' ).

The SOUNDEX function value for a string is based on the first letter and the next three consonants other than H, Y, and W. Doubled letters are counted as one letter. For example,

SOUNDEX( 'apples' ) FROM iq_dummy

is based on the letters A, P, L and S.

Multibyte characters are ignored by the SOUNDEX function.

Although it is not perfect, soundex normally returns the same number for words that sound similar and that start with the same letter.