更新时间:2021-12-10 21:45:14
只需将额外条件移到JOIN ON条件中,这样就不需要b的存在来返回结果
Just move the extra condition into the JOIN ON criteria, this way the existence of b is not required to return a result
SELECT a.* FROM a
LEFT JOIN b ON a.group_id=b.group_id AND b.user_id!=$_SESSION{['user_id']}
WHERE a.keyword LIKE '%".$keyword."%'
GROUP BY group_id