SDU Tools: Levenshtein Distance in SQL Server T-SQL

Our free SDU Tools for developers and DBAs, now includes a very large number of tools, with procedures, functions, and views. The LevenshteinDistance function calculates the Levenshtein distance between two strings.

It essentially answers the question How far apart are these two strings in terms of character edits?, where edits are inserting, deleting, or substituting a character. In this calculation, each edit has a cost of 1.

Empty and NULL values on input return NULL.

This function is computationally intensive. If you have large volumes of data to compare, consider modifying it to a table-valued function.

Find out more

You can see it in action in the main image above, and in the video here:

You can use our tools as a set or as a great example of how to write functions like these.

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http://sdutools.sqldownunder.com

2026-03-31