ASA SQL Reference
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SOUNDEX function [String]

Function 

Returns a number representing the sound of a string.

Syntax 

SOUNDEX ( string-expression )

Parameters 

string-expression    The string.

Usage 

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' )

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

Multi-byte characters are ignored by the SOUNDEX function.

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

The SOUNDEX function works best with English words. It is less useful for other languages.

Standards and compatibility 

• SQL/92    Vendor extension.

• SQL/99    Vendor extension.

• Sybase    Compatible with Adaptive Server Enterprise, except that Adaptive Server Enterprise returns a CHAR(4) result and Adaptive Server Anywhere returns an integer.

Example 

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' )