insert tuser(字段名) valuse('jack') where not exists(select 1 from tuser where 字段名='jack')
insert tuser(字段名) valuse('jack') where not exists(select 1 from tuser where 字段名='jack') ---------------------------------------------------------------- 牛!!! 第一次见到这么写Insert!
这两个人超级NB,创造了INSERTR的新写法。
if not exists(select 1 from tuser where 字段名='jack') insert tuser(字段名) valuse('jack')
if not exists(select 1 from tuser where col='jack') insert into tuser(col) select 'jack'
where not exists(select 1 from tuser where 字段名='jack')
1 对目标列(你的'用户'字段)创建唯一索引
2 先IF一下判断这个用户是否存在,不存在,再INSERT
where not exists(select 1 from tuser where 字段名='jack')
where not exists(select 1 from tuser where 字段名='jack')
----------------------------------------------------------------
牛!!!
第一次见到这么写Insert!
insert tuser(字段名) valuse('jack')
insert into tuser(col) select 'jack'