推荐课程：mysql教程。
判断字段是否存在：
drop procedure if exists schema_change; delimiter //create procedure schema_change() begin declare currentdatabase varchar(100);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 0 comment '是否上传 是否上传';end if; end// delimiter ; call schema_change();
mysql 判断字段否存在，如果存在就修改字段：
drop procedure if exists proc_temppro;if(@count>0) then alter table 表名 change column `旧列名` `新列名` varchar(30) comment '字段说明';end if;end;call proc_temppro;drop procedure if exists proc_temppro;
通过存储过程判断字段是否存在，不存在则增加：
drop procedure if exists pro_addcolumn;create procedure pro_addcolumn() beginif not exists(select 1 from information_schema.columns where table_name='component' and column_name='print_check_status') thenalter table component add print_check_status int(10) default 0;end if;if not exists(select 1 from information_schema.columns where table_name='component' and column_name='print_check_time') thenalter table component add print_check_time datetime null;end if;if not exists(select 1 from information_schema.columns where table_schema=podcloud and table_name='component' and column_name='print_check_back_reason') thenalter table component add print_check_back_reason varchar(500) default null;end if;end;call pro_addcolumn;drop procedure pro_addcolumn;------------------------------------------------------------------------------------------------drop procedure if exists pro_addindex; delimiter; create procedure pro_addindex() begin 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 pro_addindex(); drop procedure pro_addindex;
以上就是mysql判断列是否存在的详细内容。