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Oracle/PLSQL: SOUNDEX Function

This Oracle tutorial explains how to use the Oracle/PLSQL SOUNDEX function with syntax and examples.


The Oracle/PLSQL SOUNDEX function returns a phonetic representation (the way it sounds) of a string.


The syntax for the Oracle/PLSQL SOUNDEX function is:

SOUNDEX( string1 )

Parameters or Arguments

string1 is the string whose phonetic value will be returned.


The SOUNDEX function algorithm is as follows:

  1. The SOUNDEX function return value will always begin with the first letter of string1.
  2. The SOUNDEX function uses only the first 5 consonants to determine the NUMERIC portion of the return value, except if the first letter of string1 is a vowel.
  3. The SOUNDEX function is not case-sensitive. What this means is that both uppercase and lowercase characters will generate the same SOUNDEX function return value.

Applies To

The SOUNDEX function can be used in the following versions of Oracle/PLSQL:

  • Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i, Oracle 8i


Let's look at some Oracle SOUNDEX function examples and explore how to use the SOUNDEX function in Oracle/PLSQL.

For example:

SOUNDEX('tech on the net')
Result: 'T253'

Result: 'T253'

Result: 'A142'

SOUNDEX('apples are great')
Result: 'A142'

Result: 'A142'