电玩竞技场,超级魂晶,淘宝聚划算怎么参加
判断字段是否存在:
drop procedure if exists schema_change; delimiter // create procedure schema_change() begin declare currentdatabase varchar(); select database() into currentdatabase; if not exists (select * from information_schema.columns where table_schema=currentdatabase and table_name = 'rtc_order' and column_name = 'ifupsend') then alter table rtc_order add column `ifupsend` bit not null default comment '是否上传 是否上传'; end if; end// delimiter ; call schema_change();
判断索引是否存在:
drop procedure if exists schema_change; delimiter // create procedure schema_change() begin declare currentdatabase varchar(); select database() into currentdatabase; if not exists (select * from information_schema.statistics where table_schema=currentdatabase and table_name = 'rtc_phototype' and index_name = 'index_name') then alter table `rtc_phototype` add index index_name ( `imgtype` ); end if; end// delimiter ; call schema_change();
从这两段可以看出很多东西,具体可以自己试验一下
关于小编给大家介绍的mysql判断表字段或索引是否存在的内容就给大家介绍到这里,希望对大家有所帮助!
如对本文有疑问,请在下面进行留言讨论,广大热心网友会与你互动!! 点击进行留言回复
小白安装登录mysql-8.0.19-winx64的教程图解(新手必看)
Navicat连接MySQL时报10060、1045错误及my.ini位置问题
网友评论