Question

如何加入4个表并检索有关一个ID（行）的信息？

这是我到目前为止所做的：

Answer 1

根据您的评论，问题是您有多个具有相同名称的列，因此需要使用别名：

SELECT  Crs_Desc, Enrollment.Enrollme,  Enrollment.Offer_No
FROM Offerin, Course
JOIN Enrollment ON Enrollment.Offer_No = Offering.Offer_No 
JOIN Student ON Student.Std_ID = Enrollment.Std_ID

WHERE Enrollment.Std_ID = '103'
GROUP BY Enrollment.Std_ID;

如果此查询无法解决您的问题，请分享您的表格数据和预期结果

Answer 2

尝试这样的事情。

SELECT  Student.Student_ID, Course.Crs_Desc, 
    Enrollment.Std_ID, Enrollment.Offer_No, 
    Offering.Offer_No 
    FROM Student
        JOIN Enrollment
            ON Student.Student_ID = Enrollment.Std_ID
        JOIN Offering
            ON Enrollment.Std_ID = Offering.Offer_No
        JOIN Course
            ON Offering.Offer_No = Course.CourseNo
        WHERE Student_ID = '103';

此外，WHERE子句看起来可能是错误的。尝试＆＃34; WHERE Student_ID =＆＃39; 103＆＃39 ;;＆＃34;

Answer 3

试试这个：

SELECT  Student.Student_ID
       ,Course.Crs_Desc
       ,Enrollment.Std_ID
       ,Enrollment.Offer_No
       ,Offering.Offer_No 
    FROM Student
        LEFT JOIN Enrollment
            ON Student.Student_ID = Enrollment.Std_ID
        LEFT JOIN Offering
            ON Enrollment.Std_ID = Offering.Offer_No
        LEFT JOIN Course
            ON Offering.CourseNo = Course.CourseNo
        WHERE Student.Student_ID = '103';

用SQL连接四个表

3 个答案: