这是我的表offs
:
date ---------- oid ------ head ----- cnt
2012-1-9 -----13 -------- 10 -----------1
2012-1-11 --- 13 -------- 6 ----------- 2
2012-1-22 --- 13 -------- 10 -----------3
2012-1-22 --- 11 -------- 10 -----------4
我需要一个select函数,结果是max(date)
来自oid和不同的头部,就像那样:
2012-1-11 --- 13 -------- 6 ----------- 2
2012-1-22 --- 13 -------- 10 -----------3
2012-1-22 --- 11 -------- 10 -----------4
答案 0 :(得分:1)
这个查询怎么样:
SELECT a.*, b.cnt from(
SELECT MAX(Date) AS Date, oid, head
from offs group by oid, head
)a inner join offs b on a.Date=b.Date and a.oid=b.oid and a.head=b.head