SELECT CONCAT('ALTER TABLE `', table_name, '` MODIFY `', column_name, '` ', DATA_TYPE, '(', CHARACTER_MAXIMUM_LENGTH, ') CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci', (CASE WHEN IS_NULLABLE = 'NO' THEN ' NOT NULL' ELSE '' END), ';')
FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = 'hr_databus'
AND DATA_TYPE = 'varchar'
AND
(
CHARACTER_SET_NAME != 'utf8mb4'
OR
COLLATION_NAME != 'utf8mb4_general_cir'
);