select * from archives_type a left join childLei c on (a.numHead=c.numHead) and
(c.childNum=(select top 1 childNum from grandsonLei))这样只能关联到grandsonLei中的一条记录
(c.childNum=(select top 1 childNum from grandsonLei))这样只能关联到grandsonLei中的一条记录
可以的 ,就象这样!!!
select * from archives_type a left join childLei c on a.numHead=c.numHead
inner join grandsonLei g on c.childNum=g.childNum
*
from
archives_type a
left join
childLei c
on
a.numHead=c.numHead
left join
grandsonLei g
on
c.childNum=g.childNum
left join 和left join相连就可以查出我需要的结果了,谢谢大家
from table1 a left outer join table2 b on a.id=b.id left outer join table 3 c on a.id=c.id
3个表可以用left outer join连用