SELECT m.*, u1.nickname as sender_nickname, u1.avatar as sender_avatar, u2.nickname as receiver_nickname, u2.avatar as receiver_avatar FROM ( SELECT MAX(id) as id, IF(sender_id = #{userId}, receiver_id, sender_id) as chat_user_id, MAX(create_time) as latest_time FROM user_message WHERE sender_id = #{userId} OR receiver_id = #{userId} GROUP BY chat_user_id ORDER BY latest_time DESC ) as t JOIN user_message m ON t.id = m.id JOIN user_info u1 ON m.sender_id = u1.id JOIN user_info u2 ON m.receiver_id = u2.id ORDER BY m.create_time DESC SELECT m.*, u1.nickname as sender_nickname, u1.avatar as sender_avatar, u2.nickname as receiver_nickname, u2.avatar as receiver_avatar FROM user_message m JOIN user_info u1 ON m.sender_id = u1.id JOIN user_info u2 ON m.receiver_id = u2.id WHERE (m.sender_id = #{userId} AND m.receiver_id = #{targetId}) OR (m.sender_id = #{targetId} AND m.receiver_id = #{userId}) ORDER BY m.create_time ASC UPDATE user_message SET is_read = 1 WHERE receiver_id = #{userId} AND sender_id = #{senderId} AND is_read = 0 SELECT COUNT(1) FROM user_message WHERE receiver_id = #{userId} AND is_read = 0