SQL Server：SELECT DISTINCT Group By with Count

Question

我有一张桌子如下。

我可以按上述方式输出吗？

谢谢

Answer 1

这是执行此操作的MYSQL查询

SELECT id，date，msg，COUNT（id）AS count FROM table_name GROUP BY id

Answer 2

请尝试以下查询：

SELECT t1.id, t1.date, t1.msg, t2.msg_count 
FROM table_name t1 
JOIN (SELECT max(msg_id) as mid, count(*) as msg_count FROM table_name GROUP BY id) as t2 
ON(t1.msg_id=t2.mid)

Answer 3

好像你想在结果集中找到最新日期，所以查询看起来像是什么，SELECT id，max（date），msg，COUNT（id）AS count FROM table_name GROUP BY id

Answer 4

对于sql server，试试这个：

SELECT id, max(date) as date, msg, count(id) AS count 
FROM table_name 
GROUP BY id, msg

Answer 5

SELECT T.id, Q.max_date, count(T.msg)
FROM Table1 T, (select id, MAX(dateD) as max_date from Table1 group by id) Q
where Q.id=T.id
group by T.id, Q.max_date
;