我需要列出包含所选用户和消息 ID 的结果主题,如下所示:
test 1 (topic)
message id (i will add a link for this ID)
(消息表中相同主题的同一用户可能有多个记录)
-------------------------------------
TABLES
-------------------------------------
TABLE: users
id int (auto_increment)
user varchar
-------------------------------------
TABLE: topics
id int
user_id int (index)
topic varcahar
-------------------------------------
TABLE: messages
id int (auto_increment)
user_id int (index)
topic_id int (index)
message text
-------------------------------------
我确实尝试了这段代码,但出现了错误。
SELECT users.id,users.user,topics.topic,messages.id FROM users,topics,messages WHERE messages.user_id=users.id and users.user='$_GET[user]' ORDER BY topics.topic
我该怎么做?
最佳答案
SELECT u.id, u.user, t.topic, m.id
FROM topics t
LEFT JOIN users u ON u.id = t.user_id
LEFT JOIN messages m ON m.user_id = u.id
WHERE u.user = 'xyz'
ORDER BY t.topic
但是你应该转义$_GET[user]
关于php mysql 查询3个表(用户、主题、消息),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/21152901/