php - Mysql 行总是 = 1

Question

您好，我正在尝试检查数据库中是否有一行，但是对于某些原因，它一直说有但没有。我在一侧有很多 if 语句，所以我认为这就是问题所在。

<?php
 if (isset($_POST['A'])) {
$item2= mysql_real_escape_string($_POST['A']);
$item = strip_tags($item2);

$pokemonchoice= mysql_real_escape_string($_POST['B']);
$pokemonchoicee = strip_tags($pokemonchoice);



?><?php  
 if ( $pokemonchoicee == "Add to pokemon 1" ) {
    $pokemonchoicee = '1';
}
 if ( $pokemonchoicee == "Add to pokemon 2" ) {
    $pokemonchoicee = '2';
}
 if ( $pokemonchoicee == "Add to pokemon 3" ) {
    $pokemonchoicee = '3';
}
 if ( $pokemonchoicee == "Add to pokemon 4" ) {
    $pokemonchoicee = '4';
} 
 if ( $pokemonchoicee == "Add to pokemon 5" ) {
    $pokemonchoicee = '5';
}
 if ( $pokemonchoicee == "Add to pokemon 6" ) {
    $pokemonchoicee = '6';
}

 ?>

 <?php


 $query = "SELECT * FROM items WHERE item='".$item."' AND belongsto='".$_SESSION['username']."'";
if(mysql_num_rows($query)!=0)
{
echo "You do not have this item";
}
else
{
echo "You have this item";
}

 ?>

 <?php
 echo $pokemonchoicee ;
 echo $item ;
 }

 ?>

保持打印真实的位是

 <?php


 $query = "SELECT * FROM items WHERE item='".$item."' AND belongsto='".$_SESSION['username']."'";
if(mysql_num_rows($query)!=0)
{
echo "You do not have this item";
}
else
{
echo "You have this item";
}

 ?>

我删除了所有行但仍然说你有这个项目

Answer 1

mysql_num_rows()获取一个mysql结果类型资源，$query = mysql_query($query)在mysql_num_rows之前使用

Answer 2

您的 if 语句中有错误。如果返回的行数 > 0，则您正在打印“您没有此项目”。应该是相反的，所以改变!=检查或让回声交换位置