delete a from a left join b on a.id=b.aid where b.aid is null;

------解决方案--------------------
是不是因为id没指明是a表的，应该是delete from a where a.id not in(select a.id from a,b where a.id=b.aid);


------解决方案--------------------
delete from a where not exists(select 1 from b where a.id=aid);


------解决方案--------------------
SQL code
create table a(id int);
create table b (aid int);
insert a values (1),(2),(3);
insert b values(1);
delete from a where not exists(select 1 from b where a.id=aid);
select * from a 
+------+
| id   |
+------+
|    1 |
+------+

------解决方案--------------------
探讨


delete from a from a left join b on a.id=b.aid where b.aid is null;


------解决方案--------------------
探讨


引用:
delete from a from a left join b on a.id=b.aid where b.aid is null;


会报错：You have an error in your SQL syntax; check the manual that corresponds to your MySQL server versi……


------解决方案--------------------
where isnull（b.aid）
是不是这样的？