mysql> GRANT ALL PRIVILEGES ON *.* TO zhangsan@'%' IDENTIFIED BY '123'; ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'IDENTIFIED BY '123'' at line 1

这个错误的原因是语法错误，正确的语法应该是在GRANT ALL PRIVILEGES ON *.* TO zhangsan@'%'后面加上WITH GRANT OPTION，并且在IDENTIFIED BY '123'前面加上一个关键字PASSWORD。正确的语法应该是：

GRANT ALL PRIVILEGES ON *.* TO zhangsan@'%' WITH GRANT OPTION IDENTIFIED BY '123';

这样就可以成功授权了。