有没有更好的方法在SQL中一次从3个用户名获取电子邮件？

Question

I have 3 username, ie: usernameA,usernameB,usernameC. And I have also their email in a table, ie: usernamea@gmail,usernameb@gmail,usernamec@gmail. I don't know how to get these emails at once from that 3 username. I can do it by this:

$q=mysql_query("SELECT email FROM t_un WHERE username='usernameA'");
$f=mysql_fetch_object($q);
$emailA=$f->email;

$q=mysql_query("SELECT email FROM t_un WHERE username='usernameB'");
$f=mysql_fetch_object($q);
$emailB=$f->email;

$q=mysql_query("SELECT email FROM t_un WHERE username='usernameC'");
$f=mysql_fetch_object($q);
$emailC=$f->email;

but that's uncomfortable for me. Is there any better way to get that emails from 3 username at once in SQL? thanks.

Answer 1

I don't know if I understand your need, but try it out:

SELECT GROUP_CONCAT(t_un.email) AS users FROM t_un WHERE username='usernameA' OR username='usernameB' OR username='usernameC';

It will return a comma-separated field called users. You may want another separator, then you can try this:

SELECT GROUP_CONCAT(t_un.email SEPARATOR ";") AS users FROM .......