Question

我需要有关sql查询的帮助

我有这张桌子（post_table）：

+----+---------+--------+
| id | topicId | userId |
+----+---------+--------+
| 1  | 1       | kalle  |
| 2  | 1       | pelle  |
| 3  | 2       | laban  |
| 4  | 2       | kalle  |
| 5  | 2       | kalle  |
| 6  | 2       | kalle  |
| 7  | 1       | kalle  |
| 8  | 1       | kalle  |
| 9  | 2       | laban  |
| 10 | 1       | laban  |
| 11 | 2       | kalle  |
| 12 | 2       | kalle  |
| 13 | 3       | laban  |
| 14 | 1       | kalle  |
| 15 | 2       | kalle  |
| 16 | 1       | kalle  |
| 17 | 3       | laban  |
| 18 | 4       | laban  |
| 19 | 5       | laban  |
| 20 | 6       | pelle  |
+----+---------+--------+

我想只获得userId“kalle”没有阅读帖子的行，它们是

+----+---------+--------+
| id | topicId | userId |
+----+---------+--------+
| 13 | 3       | laban  |
| 17 | 3       | laban  |
| 18 | 4       | laban  |
| 19 | 5       | laban  |
| 20 | 6       | pelle  |
+----+---------+--------+

topicId 1已被idI 1,7,8,14

中的userId“kalle”读取

topicId 2已被userId“kalle”读取，内容为id 4,5,6,11,12,15

然后我还希望获得topicId中的唯一值，id 13或17可以显示但不能同时显示。

我希望你明白我在追求什么

Answer 1

SELECT * FROM POST_TABLE WHERE ID IN
(
        SELECT MAX(ID)  FROM POST_TABLE WHERE TOPICID NOT IN
              (
                SELECT DISTINCT TOPICID  FROM POST_TABLE WHERE USERID ='kalle'
              )
        GROUP BY TOPICID
)

论坛MySQL查询

1 个答案: