PHP判断数据库中的记录是否存在的方法

<?php  

  

$sql="select * from checklist where game_id=$gid and task='$task' and status='$status'";  

$result=mysql_query($sql);  

  

$row = mysql_fetch_array($result, MYSQL_ASSOC);  

  

    if (!mysql_num_rows($result))  

        {  

            echo "record doesn't exist~~~~~!!!!!!";  

        }  

    else  

        {  

           // echo mysql_num_rows($result)."\n";  

            echo $row['game_id'];  

            echo $row['task'];  

        }  

?>