我正在尝试从mysql数据库中获取结果。这是我的问题

SET @rownum := 0;

SELECT rank,playerName FROM (
                SELECT @rownum := @rownum + 1 AS rank,numberOfDinner
                FROM players ORDER BY numberOfDinner DESC
                ) as result WHERE playerName='Arifa';

但是在执行这个查询时，我得到了以下错误

我的“玩家”表有以下列：

id  
playerEmail     
playerName  
playerImage     
playerFacebook  
playerTwitter   
playerYouTube   
numberOfDinner