wp-config.php file there are two lines that define your MySQL database charset and collation.
define( 'DB_CHARSET', 'utf8' ); define( 'DB_COLLATE', 'utf8_general_ci' );
These lines should match those of your database but it’s not always like that; maybe you want to migrate the database content into another one (which is
CHARACTER SET utf8 COLLATE utf8_general_ci) or maybe you just want to set reasonable defaults for your blog (avoiding the defaults, which more often than not are unknown).
Enter Utf8ize. It’s a simple WordPress Plugin but it’s a life-saver.
The goal in these conversions is always to decide on what charset/collation combination you want to use (UTF8 being the best choice in almost all scenarios) then to convert all tables/columns in your database to use that charset. At that point you can set DB_COLLATE and DB_CHARSET to the desired charset and collation to match.
It reads your database and generates SQL statements for every table and column. Then you simply copy/paste the statements into phpMyAdmin or Adminer and execute.
Just remember to change your
wp-config.php accordingly and pay attention to the generated SQL statements for the specific collation (may be
utf8_unicode_ci). Set the correct values in the
wp-config.php right after you run the SQL statements and you’re done.