select host,user,authentication_string from mysql.user; -- 查询用户
-- drop user 'topingr_reader'@'%'; -- 删除用户
grant all privileges on test_database.* to 'topingr_reader'@'%' identified by 'tpreader@123' with grant option; -- 创建用户
GRANT SELECT ON topingr.* TO 'topingr_reader'@'%' IDENTIFIED BY "tpreader@123"; -- 授权