PHP/SQL，简单选择哪里获取“值"；作为列

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问题描述

$account = "proot";

        $sql_check_account = mysqli_query($connect, "SELECT username FROM proot_accounts WHERE username = $account");

    if(!$sql_check_account)
            die(mysqli_error($connect));

where 子句"中的未知列proot"

Unknown column 'proot' in 'where clause'

同:

 $sql_check_account = mysqli_query($connect, 'SELECT username FROM proot_accounts WHERE username = "'.$account.'"');

或者

 $sql_check_account = mysqli_query($connect, "SELECT username FROM proot_accounts WHERE username =".$account);

什么可以使变量 $account 作为列执行?我不明白这里的问题...

What can make the variable $account perform as a column ? I don't get the problem here...

谢谢！

推荐答案

你需要在它周围加上引号.

You need to put quotes around it.

mysqli_query($connect, "SELECT username FROM proot_accounts WHERE username = '$account'");

您还应该探索 PHP 中准备好的 SQL 语句.他们将省去很多这些格式问题.

You should also explore prepared SQL statements in PHP. They will save a lot of these formatting headaches.

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