下面的SELECT語句如何使查詢GROUP BY X DESC
select *
from messages
where receiverID = '5'
group BY senderID
order by id DESC
數據庫:
id | senderID | receiverID | message
1 | 245 | 5 | test 1
2 | 89 | 5 | test 2
3 | 79 | 5 | test 3
4 | 245 | 5 | test 4
5 | 245 | 5 | test 5
對於senderID = 245我預計到id = 5返回該行,但它dosent它返回id = 1的行,但我想要最後一行。如何實現這一目標?
回報:
id | senderID | receiverID | message
1 | 245 | 5 | test 1
2 | 89 | 5 | test 2
3 | 79 | 5 | test 3
喔我做到了:d
所以這是工作,對任何人有類似問題的代碼
SELECT * FROM (SELECT * FROM messages WHERE
receiverID = '5' ORDER BY id DESC) AS m GROUP BY senderID ORDER BY id DESC
你能不能改一下這個問題嗎?也許你試圖實現的一個例子列表結果 – 2012-02-16 10:12:27
爲什麼你在這裏使用'GROUP BY'? – piotrm 2012-02-16 10:20:42
我使用GROUP BY,因爲我想要每個senderID的最後一行。 – Ben 2012-02-16 10:25:20