php - 在 mysql_query 函数内传递 PHP 变量

Question

我想在 mysql_query 中传递一个 php 变量，例如:

$tty = '217';   

$num_of_comments = mysql_query("SELECT count(*) FROM comments WHERE img_id =  '.$tty.'");
$num_of_comments1 = mysql_fetch_array($num_of_comments);
$num_of_comments2 = $num_of_comments1[0];
echo $num_of_comments2 ;

但是，我无法获取 num_of_comments2 中所需的值。它在回显时返回 0。

Answer 1

正如颜色编码所示，您的查询是错误的。您还可以通过echo您的查询来调试它:

SELECT count(*) FROM comments WHERE img_id =  '.217.'

明显不正确!

$tty = '217';   

$sql = mysql_query("SELECT count(*) FROM comments WHERE img_id = ".intval($tty));
$row = mysql_fetch_row($sql);
$number = $row[0];
echo $number;

用于获取值的替代单行代码:

list($number) = mysql_fetch_row(mysql_query("select count(*) from `comments` where `img_id`=".intval($tty)));