如何在3个表之间建立外部关联

Question

－－试试select 店铺=IsNULL(t1.shop1,IsNULL(t2.shop2,t3.shop3)),
       季节=IsNULL(t1.seas1,IsNULL(t2.seas2,t3.seas3)),
       quty1=IsNULL(sum(t1.quty1),0),
       quty2=IsNULL(sum(t2.quty2),0),
       quty3=IsNULL(sum(t1.quty3),0)
from t1 full join t2 on t1.shop1=t2.shop2 and t1.seas1=t2.seas2
        full join t3 on t1.shop1=t3.shop3 and t1.seas1=t3.seas3
group by shop1,shop2,shop3,seas1,seas2,seas3

Answer 1

只是排序规则，你可以后面加一个
order by Left(IsNULL(t1.seas1,IsNULL(t2.seas2,t3.seas3)),4) desc