sql語法返回mysql_num_rows（）期望參數1是資源，布爾給定

Question

我有以下一段代碼。讓我發狂。找不到我的錯誤。看起來像在我的sql語法中使用限制有衝突，並且變量$ result中的mysql_query不返回任何內容。

<?php 

$sql = " select * from `share` where (`category` LIKE '$category' and `country` LIKE '$country' and `city` LIKE '%$city_name%' and `job_title` LIKE '%$job_name%' and `user_id`!='$session_user_id') 
     order by `share_id` desc LIMIT 3; "; 

$result = mysql_query($sql); 

if(mysql_num_rows($result) ==0){ 
    echo"success"; 
} 

?> 

Answer 1

引起問題的字符串連接問題。

$sql = "select * from `share` 
     where 
      (`category` LIKE '". $category ."' 
      and `country` LIKE '". $country ."' 
      and `city` LIKE '%". $city_name ."%' 
      and `job_title` LIKE '%". $job_name ."%' 
      and `user_id` != '". $session_user_id ."') 
     order by `share_id` desc 
     limit 3";