mysql - 3 个表的内部连接

Question

我尝试使用 this 中的示例加入三个表问题。但是我遇到了以下错误。

错误:

#1054 - Unknown column 'referrer.Referrer_Name' in 'field list' 

代码:

    SELECT pupils.Pupils_Surname, 
            pupils.Pupils_FirstName,
            referrer.Referrer_Name, 
            progress_track.test_1,  
            progress_track.test_2, 
            progress_track.test_3, 
            progress_track.test_4, 
            progress_track.test_5, 
            progress_track.test_6, 
            progress_track.test_7, 
            progress_track.test_8, 
            progress_track.test_9, 
            progress_track.test_10
    FROM pupils
    INNER JOIN progress_track ON progress_track.Progress_Report_Pupils_ID=pupils.Pupils_ID;
    INNER JOIN referrer ON  pupils.Pupils_Referrer, referrer.Referrer_ID ;

Answer 1

首先让我突出显示您查询中的错误:

1) 查询因拼写错误而意外结束

2) 最后一个 INNER JOIN 包含语法错误。

我在下图中突出显示了错误:

补救措施:

SELECT
    pupils.Pupils_Surname,
    pupils.Pupils_FirstName,
    referrer.Referrer_Name,
    progress_track.test_1,
    progress_track.test_2,
    progress_track.test_3,
    progress_track.test_4,
    progress_track.test_5,
    progress_track.test_6,
    progress_track.test_7,
    progress_track.test_8,
    progress_track.test_9,
    progress_track.test_10
FROM
    pupils
INNER JOIN progress_track ON progress_track.Progress_Report_Pupils_ID = pupils.Pupils_ID
INNER JOIN referrer ON pupils.Pupils_Referrer = referrer.Referrer_ID;

回应您的评论:

Could you please post this as an answer. It worked but it still did not show any data from the referrer table

• 如果不满足加入条件那么你就看不到了数据，除非您使用 LEFT JOIN。请先检查您的数据。
• 请确保您拥有满足以下两个条件的数据:progress_track.Progress_Report_Pupils_ID = pupils.Pupils_ID
referrer.Referrer_ID = pupils.Pupils_Referrer