normalizing accented characters in MySQL queries

Question

I\'d like to be able to do queries that normalize accented characters, so that for example:

é, è, and ê

are all treated as \'e\', in querie

Answer 1

The reason for the error is not the table but the characterset of your input, i.e. the 'rené' in your query. The behaviour depends on the character_set_connection variable:

The character set used for literals that do not have a character set introducer and for number-to-string conversion.

Using the MySQL Client, change it using SET NAMES:

A SET NAMES 'charset_name' statement is equivalent to these three statements:

SET character_set_client = charset_name;
SET character_set_results = charset_name;
SET character_set_connection = charset_name;

(from http://dev.mysql.com/doc/refman/5.5/en/charset-connection.html)

Example output:

mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from User where username = 'rené' collate utf8_general_ci;
ERROR 1253 (42000): COLLATION 'utf8_general_ci' is not valid for CHARACTER SET 'latin1'

mysql> set names utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from User where username = 'rené' collate utf8_general_ci;
Empty set (0.00 sec)

Altenatively, use can explicitly set the character set using a 'character set introducer':

mysql> set names latin1;
Query OK, 0 rows affected (0.00 sec)

mysql> select * from User where username = _utf8'rené' collate utf8_general_ci;
Empty set (0.00 sec)

I know this question is pretty old but since Google led me here for a related question, I though it still deserves an answer :)