MYSQL find how different two text fields are?

Question

I'm storing the HTML content of emails in my database.

If I store two of the same emails in my database, that are only a little different because of personalization (one might say "Hello Stephen, thank you for subscribing...", and the other "Hello Andrew, thank you for subscribing...").

How can I tell that these text fields are only slightly different? (maybe get a percentage saying they're 95% alike).

Answer 1

Here's a good starting point for MySQL: http://www.artfulsoftware.com/infotree/queries.php#552

A Levenshtein distance is the number of edits required to turn one string into another. You could probably mess with dividing that distance by the length of the string to get a percentage of sorts.

For PHP, there is a builtin Levenshtein function: http://www.php.net/manual/en/function.levenshtein.php

Answer 2

This could also help: http://www.php.net/manual/en/function.similar-text.php . similar_text() returns the number of matching chars in both strings.