我正在尝试为每个requester_req
组选择最大值customer
,但是在尝试了许多不同的方法之后,我的结果集继续显示每一行,而不是客户组的最大值。
查询:
SELECT
x2.customer,x.customer_req,x2.requester_name,MAX(x2.requester_req) AS requester_req
FROM x,x2
WHERE x.customer = x2.customer
GROUP BY x2.customer,x.customer_req
ORDER BY x2.customer
样本结果集:
customer customer_req requester_name requester_req
Bob's Burgers 7 Bob 9
Bob's Burgers 7 Jon 12
Hello Kitty 9 Jane 3
Hello Kitty 9 Luke 7
预期结果集:
customer customer_req requester_name requester_req
Bob's Burgers 7 Jon 12
Hello Kitty 9 Luke 7
我在group by子句中搞砸了吗?我无法数出切换次数并获得相同结果集的次数。
非常感谢您的帮助!