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'];  
        }  
?>