一、功能場景
需求展示:
查詢出好友給我發的最近一條信息
二、數據庫設置
id
:主鍵idsend_user_id
:發送人idreceive_user_id
:接收人idcontent
:發送內容send_time
:發送時間
三、代碼實現
需求:查詢用戶id爲1的所有的並且最新的聊天信息
一、未查詢前的所有數據:
二、sql:
SELECT
*
FROM
(
SELECT
*
FROM
fa_hx_chat_content
WHERE
send_time IN (
SELECT
MAX( send_time )
FROM
fa_hx_chat_content
WHERE
receive_user_id = 1
OR send_user_id = 1
GROUP BY
CONCAT(
IF
( send_user_id > receive_user_id, send_user_id, receive_user_id ),
IF
( send_user_id < receive_user_id, send_user_id, receive_user_id )))
AND ( receive_user_id = 1 OR send_user_id = 1 )
ORDER BY
id DESC
) c
GROUP BY
c.send_time ASC
三、查詢後的數據: