但在添加重复用户名时,不会出现错误消息。我是否遗漏了任何代码,或者我需要更改代码?<?(DB_HOST,DB_USER,DB_PASSWORD) or die("Failed to connect to MySQL: " . mysql_error());
$db=mysql_select_db(DB_NAME,$con) or die("Failed to connect to MySQL: " . mysql</em
目前我正在使用MySQL5.7进行开发,5.6处于生产阶段。每次在开发中使用GROUP BY运行查询时,我都会得到一些错误,如"Error Code: 1055.Expression #1 of SELECT list is not in group by“ FROM countries c, images i GROUP BY c.id; Fixed函数,但主要问题是它在mysql5.6中不可
如何仅显示来自该结果的重复用户?(理想情况下只显示每个副本一次)。(SELECT user1 AS user FROM friendships WHERE user2 = 'johnsmith') (SELECT user2AS user FROM friendships WHERE user1 = 'johnsmith') (SELECT user1 AS user FROM f