SELECT CONCAT('ALTER TABLE `', TABLE_NAME,'` CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;') AS mySQL FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA= "myschema" AND TABLE_TYPE="BASE TABLE"
Change “myschema” to your db_name , phpmyadmin will print out the commands you need to run… If any of them are trimmed with a “…” click “print view” select all commands and run.