Can't get REGEXP to work properly with utf8
Posted by: Oskar Joelson
Date: November 15, 2005 06:54AM


I recently changed the collation/character set in the whole database for a project I'm working on to utf8. After a while I realized that REGEXP didn't work as it used to. I looked in the manual and saw that REGEXP was not multibyte safe. For example, if I have column called 'info' in a table 'news' and a row with the string "början" in colum 'info' and I would use these queries:

(I have simplified these queries so it would be more obvious, ordinarily the regexp's are much more complex, so I cannot for example use LIKE instead)

This used to give the same result, I would get the row containing the string "början" whatever case I used. However, when I changed the database to utf8 (from latin1) the second query wouldn't work. I can still do REGEXP searches with different case as long as the characters are non-"foreign" (åäö and so on).

I found this in :
"REGEXP and RLIKE use the current character set (cp1252 Latin1 by default) when deciding the type of a character. Warning: These operators are not multi-byte safe."

Does this mean that REGEXP will only work with "foreign" characters if the column has a latin1 collation? Or does it mean that I can change the "current character set" to utf8 and REGEXP will work with "foreign" characters? Because I have tried that and it will still not work.
Everything is set to utf8: character_set_client, character_set_connection, character_set_database, character_set_results, character_set_server, character_set_system, and all collations are utf8. I have changed the MySQL-configuration (my.ini) so that default-character-set is utf8_general_ci (I have tried utf8_swedish_ci too) for both client and server. It wont work. But if I change collation only for the column I'm doing REGEXP's on to latin1 it works!

Am I forced to use latin1 if I want to do proper REGEXP selects? Has anyone else had this problem? I would be ever grateful for any help.


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Can't get REGEXP to work properly with utf8
November 15, 2005 06:54AM

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