獲得MySQL中

Question

DISTINCT IDS我有一個表的結構是這樣的：

Comments table 
id  review_id user_id created  comments deleted 
1  10   28  2011-10-12 "hi"  0 
2  11   28  2011-10-13 "yo"  0 
3  10   28  2011-10-15 "bye" 0 

我想從每個審查創建降序排序的最新評論。所以我有這樣的事情：

SELECT DISTINCT review_id, 'comments' as type FROM comments as MyTable WHERE 
user_id=28 AND deleted=0 ORDER BY created DESC LIMIT 30 

所以在上面的表中，我想要的行id = 3，然後id = 2返回。

Answer 1

實例查詢：

http://data.stackexchange.com/stackoverflow/s/2143/getting-distinct-ids-in-mysql

SELECT id,comment 
FROM comments 
WHERE id IN (
    SELECT MAX(id) 
    FROM comments 
    WHERE user_id=28 AND deleted=0 
    GROUP BY review_id) 
ORDER BY created DESC 

Answer 2

請在你的代碼的代碼整合。

表數據：

id  review_id user_id created  comments deleted 
1  10   28  2011-10-12 "hi"  0 
2  11   28  2011-10-13 "yo"  0 
3  10   28  2011-10-15 "bye" 0 

運行查詢：

SELECT DISTINCT id, review_id, 'comments' AS TYPE 
FROM mytable 
WHERE user_id = 28 
AND deleted = 0 
AND id = (
    SELECT max(id) 
    FROM mytable 
) 

結果：

id review_id TYPE 
3 10  comments