我需要在用户的收件箱中将消息显示为对话。由发件人分组并显示最后一条消息(从发件人收到的最后一封邮件或我对该发件人的最新回复)。
到目前为止,我当前的MySQL查询仅显示所有收到的消息而没有任何分组。
这是我的数据库结构:
+-----------------------------------------------------------------------------------+
| users_messages |
+-----------------------------------------------------------------------------------+
| message_ID | from_id | to_id | date | subject | body | unread | delete1 | delete2 |
+-----------------------------------------------------------------------------------+
+---------------------+
| users |
+---------------------+
| id | username | ...
+----+----------+-----+
这是我当前的查询:
$result = $DB->query("SELECT p.*, p.sender as sender, m.*
FROM " . DB_PREFIX . "messages p
LEFT JOIN " . DB_PREFIX . "members m ON p.sender=m.member_id
WHERE p.receiver='" . $SESSION->conf['member_id'] . "' AND delete2=0
ORDER BY p.senddate DESC
LIMIT " . (($page - 1) * $PREFS->conf['per_page']) . ", " . $PREFS->conf['per_page']);
答案 0 :(得分:3)
有点乱 - 但应该适合你:
SELECT
*
FROM
user_messages
WHERE
message_ID IN (
SELECT
MAX(message_ID)
FROM
(SELECT
IF(m.from_id = <THE USER ID>, m.to_id, m.from_id) as other_user_id,
m.message_id
FROM
users_messages m
WHERE
m.from_id = <THE USER ID> OR m.to_id = <THE USER ID>) me
GROUP BY
other_user_id
)
ORDER BY
message_id DESC