在 MySQL 中获取 DISTINCT id

Question

我有一个这样的表结构：

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

我想从按创建的 DESC 排序的每条评论中获取最新评论。所以我有这样的事情：

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

所以在上表中，我希望返回 id = 3 然后 id = 2 的行。

Answer 1

请将此代码集成到您的代码中。

表格数据：

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

运行查询：

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

结果：

id  review_id    TYPE
3   10       comments

Answer 2

示例查询：

https://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