Mysql 如何同时使用“分组依据”和“按条件订购”

如何同时使用group by和order by条件

您没有要分组的聚合。但如果你这样做了，它看起来会像这样

SELECT n.*, u.* 
  FROM notice AS n 
  LEFT JOIN user AS u 
    ON n.userid = u.user_id 
 WHERE  n.interitor = '13' 
   AND n.userid != '13' 
   AND n.deleted = '0'  
  GROUP BY object_id
 ORDER BY createdate  DESC

---

GROUP BY

只需在

ORDER BY

之前，通常当您使用GROUP BY时，您将使用聚合函数。您通常不会像stringsAll那样解析整数。我所做的是更新select、GROUP BY和ORDER BY子句。

SELECT
    SUM(n.column) AS sumcolumn,
    u.column1,
    u.column2
FROM
    notice AS n 
LEFT JOIN
    user AS u 
        ON n.userid = u.user_id 
WHERE
    n.interitor = '13' 
    and n.userid != '13' 
    and n.deleted = '0'  
GROUP BY
    u.column1,
    u.column2
ORDER BY
    u.column1,
    u.column2;