Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE)

# echo 'alter database zabbix collate utf8_bin;' | mysql -u root -p
# echo 'show tables;' | mysql -N -u username -p password zabbix | \
> perl -ne 'chomp; print "ALTER TABLE $_ CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;\n"' | \
> mysql -u username -p password zabbix