我正在尝试检查数据库是否存在特定组合.
表: conversations
+----+
| id |
+----+
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
+----+
表: conversations_users
+----+--------------+------+
| id | conversation | user |
+----+--------------+------+
| 1 | 1 | 1 |
| 2 | 1 | 2 |
| 3 | 2 | 1 |
| 4 | 2 | 2 |
| 5 | 2 | 3 |
| 6 | 2 | 4 |
| 7 | …以下是我的数据库的样子:
表: conversations
+----+--------+--------+
| id | user_1 | user_2 |
+----+--------+--------+
| 1 | 1 | 2 |
| 2 | 2 | 3 |
| 3 | 1 | 3 |
+----+--------+--------+
表: messages
+----+--------------+------+
| id | conversation | text |
+----+--------------+------+
| 1 | 1 | hej |
| 2 | 1 | test |
| 3 | 2 | doh |
| 4 | 2 | hi |
| 5 | 3 | :) | …