error
解决MYSQL的错误：Got a packet bigger than ‘max_allowed_packet’ bytes
数据库客户端和数据库服务器端器均有自己的max_allowed_packet变量，因此，如你打算处理大的信息包，必须增加客户端和服务器上的该变量配置数值。
一般情况下，服务器默认max-allowed-packet为1MB，客户端的max-allowed-packet为16MB。
[root@ocp init.d]# mysql -hlocalhost -pabcd1234 -S /data/mysql/data/mysqld.sock
ERROR 1862 (HY000): Your password has expired. To log in you must change it using a client that supports expired passwords.
很明显报错显示：change it using a client that supports expired passwords
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement
解决方法：alter user root@‘localhost’ identified by ‘abcd1234’;不是update mysql.user set authentication_string=password(‘abcd1234’) where user=‘root’;
ERROR 1222 (21000): The used SELECT statements have a different number of columns
union/union all 中SELECT 列表中的表达式在数量上必须匹配或是显示使用NULL来补足。
