by default mysql is installed as latin1 and sometimes it causes problems when your data is not always latin1.
Follow the steps to change mysql to utf and also convert existing databases to UTF8
#1 backup your databases and convert it to UTF8
mysqldump -uusername -ppassword -c -e --default-character-set=utf8 --single-transaction --skip-set-charset --add-drop-database -B dbname -r dbname.utf8.dump.sql
do this for each of your databases.
#2 shutdown mysql
service mysqld stop
#3 edit /etc/my.cnf
ADD to [mysqld] section
#
init_connect='SET collation_connection = utf8_unicode_ci'
init_connect='SET NAMES utf8'
character-set-server=utf8
collation-server=utf8_unicode_ci
skip-character-set-client-handshake
also
[client]
default-character-set=utf8
#4 restart mysqld
service mysqld start
#5 import your databases
mysql -u user -p < dbname.utf8.dump.sql
