select a.* from company a left join menber b on a.emai=b.emai where isnull(b.emai)or select a.* from company a left join menber b on a.emai=b.emai where b.emai is null
上述代码可以生成一个新的表, 不知道你的MY SQL是否支持DELETE a.* from company a left join menber b on a.emai=b.emai where b.emai is null
delete from company where email not in (select email from menber);[align=center]====思想重于技巧==== [/align]
用IN的效率低, 用 select a.* into newtt from company a left join menber b on a.emai=b.emai where b.emai is null好一点
select a.* from company a left join menber b on a.emai=b.emai where isnull(b.emai)or select a.* from company a left join menber b on a.emai=b.emai where b.emai is null
delete commpany.* from commpany left join member on commpany.email=member.email and member.email is NULL
delete from commpany using commpany left join member on commpany.email=member.email where member.email is null;
on a.emai=b.emai where isnull(b.emai)or
select a.* from company a left join menber b
on a.emai=b.emai where b.emai is null
不知道你的MY SQL是否支持DELETE a.* from company a left join menber b
on a.emai=b.emai where b.emai is null
where email not in (select email from menber);[align=center]==== 思想重于技巧 ====
[/align]
用
select a.* into newtt from company a left join menber b
on a.emai=b.emai where b.emai is null好一点
on a.emai=b.emai where isnull(b.emai)or
select a.* from company a left join menber b
on a.emai=b.emai where b.emai is null