SOUNDEX

Return the Soundex string. This function calculates the Soundex key for a string, allowing comparison of words that sound similar.

Syntax

SOUNDEX(str)

Description

Returns a soundex string from str. Two strings that sound almost the same should have identical soundex strings. A standard soundex string is four characters long, but the SOUNDEX() function returns an arbitrarily long string. You can use SUBSTRING() on the result to get a standard soundex string. All non-alphabetic characters in str are ignored. All international alphabetic characters outside the A-Z range are treated as vowels.

Important: When using SOUNDEX(), you should be aware of the following details:

• This function, as currently implemented, is intended to work well with strings that are in the English language only. Strings in other languages may not produce reasonable results.

• This function implements the original Soundex algorithm, not the more popular enhanced version (also described by D. Knuth). The difference is that original version discards vowels first and duplicates second, whereas the enhanced version discards duplicates first and vowels second.

Examples

SOUNDEX('Hello');
+------------------+
| SOUNDEX('Hello') |
+------------------+
| H400             |
+------------------+

SELECT SOUNDEX('MariaDB');
+--------------------+
| SOUNDEX('MariaDB') |
+--------------------+
| M631               |
+--------------------+

SELECT SOUNDEX('Knowledgebase');
+--------------------------+
| SOUNDEX('Knowledgebase') |
+--------------------------+
| K543212                  |
+--------------------------+

SELECT givenname, surname FROM users WHERE SOUNDEX(givenname) = SOUNDEX("robert");
+-----------+---------+
| givenname | surname |
+-----------+---------+
| Roberto   | Castro  |
+-----------+---------+

See Also

• SOUNDS LIKE()

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