select a.k, count(decode(b.lb,1,1,null)) lb1 , count(decode(b.lb,2,1,null)) lb2, count(decode(b.lb,3,1,null)) lb1 from tt_a a left join tt_b b on a.k = b.k group by a.k在A表的k字段上建立索引,在B表的k字段上建立索引
补充说明一下,在表B中不一定包含所有表A中的记录! ------------- 做个外连接关联以下就行了 select a.k,sum(decode(b.lb,1,1,0)) lb1,sum(decode(b.lb,2,1,0)) lb2,sum(decode(b.lb,3,1,0)) lb3 from a,b where a.k=b.k(+) group by a.k
count(decode(b.lb,3,1,null)) lb1
from tt_a a
left join tt_b b on a.k = b.k
group by a.k在A表的k字段上建立索引,在B表的k字段上建立索引
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做个外连接关联以下就行了
select a.k,sum(decode(b.lb,1,1,0)) lb1,sum(decode(b.lb,2,1,0)) lb2,sum(decode(b.lb,3,1,0)) lb3 from a,b where a.k=b.k(+) group by a.k