Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Amazon Redshift will no longer support the use of Python UDFs after June 30, 2026. We will start enforcing it in phases. For more information on the details of Python end of life and migration options, see the blog post that was published on June 30, 2025.

SOUNDEX function

The SOUNDEX function returns the American Soundex value consisting of the first letter of the input string followed by a 3–digit encoding of the sounds that represent the English pronunciation of the string that you specify. For example, Smith and Smyth have the same Soundex value.

Syntax

SOUNDEX(string)

Arguments

Return type

VARCHAR(4)

Usage notes

The SOUNDEX function converts only English alphabetical lowercase and uppercase ASCII characters, including a–z and A–Z. SOUNDEX ignores other characters. SOUNDEX returns a single Soundex value for a string of multiple words separated by spaces.

SELECT SOUNDEX('AWS Amazon');
            
+---------+
| soundex |
+---------+
| A252    |
+---------+

SOUNDEX returns an empty string if the input string doesn't contain any English letters.

SELECT SOUNDEX('+-*/%');

+---------+
| soundex |
+---------+
|         |
+---------+

Examples

To return the Soundex value for Amazon, use the following example.

SELECT SOUNDEX('Amazon');

+---------+
| soundex |
+---------+
| A525    |
+---------+

To return the Soundex value for smith and smyth, use the following example. Note that the Soundex values are the same.

SELECT SOUNDEX('smith'), SOUNDEX('smyth');

+-------+-------+
| smith | smyth |
+-------+-------+
| S530  | S530  |
+-------+-------+