mysql在创建用户或者设置权限，操作mysql库时
出现以下错误：
Column count of mysql.useris wrong. Expected 43, found 42. Created with MySQL 50552, nowrunning 50636. Please use mysql_upgrade to fix thiserror.
出现问题的原因：更新mysql版本后出现了新旧版本不匹配的问题！
解决方法：使用命令：mysql_upgrade -u root -p 更新mysql库
Looking for 'mysql' as: mysql
Looking for 'mysqlcheck' as: mysqlcheck
Running 'mysqlcheck with default connection arguments
Warning: Using a password on the command line interface can beinsecure.
Running 'mysqlcheck with default connection arguments
Warning: Using a password on the command line interface can beinsecure.
mysql.columns_priv OK
mysql.db OK
mysql.event OK
mysql.func OK
mysql.general_log OK
mysql.help_category OK
mysql.help_keyword OK
mysql.help_relation OK
mysql.help_topic OK
mysql.host OK
mysql.ndb_binlog_index OK
mysql.plugin OK
mysql.proc OK
mysql.procs_priv OK
mysql.proxies_priv OK
mysql.servers OK
mysql.slow_log OK
mysql.tables_priv OK
mysql.time_zone OK
mysql.time_zone_leap_second OK
mysql.time_zone_name OK
mysql.time_zone_transition OK
mysql.time_zone_transition_type OK
mysql.user OK
Running 'mysql_fix_privilege_tables'...
Warning: Using a password on the command line interface can beinsecure.
Running 'mysqlcheck with default connection arguments
Warning: Using a password on the command line interface can beinsecure.
Running 'mysqlcheck with default connection arguments
Warning: Using a password on the command line interface can beinsecure.
test.stu OK
OK
更新成功！！！！！