[英]Using inner join as ALIASES with multiple tables
我在下面有這些表:
create table student(
studentName varchar (40) not null,
studentRollNo varchar (30) primary key, -- also acts as username
studentPassword varchar(30) NOT NULL,
studentGender varchar(7) default NULL
);
create table supervisors(
supervisorID varchar(30) foreign key references Faculty(facultyID) unique,
sWorkLoad int default null,
CHECK (sWorkLoad<=6 and sWorkLoad>=0)
);
create table co_supervisors(
co_supervisorID varchar(30) foreign key references Faculty(facultyID) unique,
csWorkLoad int default null,
CHECK (csWorkLoad<=6 and csWorkLoad>=0)
);
create table studentGroup(
groupID int IDENTITY(1,1) primary key ,
Member1rollNo varchar(30) foreign key references student(studentRollNo) default NULL, -- member 1
Member2rollNo varchar(30) foreign key references student(studentRollNo) default NULL, -- member 2
Member3rollNo varchar(30) foreign key references student(studentRollNo) default NULL, -- member 3
supervID varchar(30) foreign key references supervisors(supervisorID),
co_supervID varchar(30) foreign key references co_supervisors(co_supervisorID) default NULL,
projectTitle varchar(100) not null,
projectDetails varchar (500) default NULL
);
create table FYP1(
groupID int foreign key references studentGroup(groupID),
);
我想顯示在 FYP1 中注冊的學生詳細信息。 與他們的主管、co_supervisors 和項目名稱。
但是我不能這樣做,到目前為止我所做的就是這個。
select sg.Member1rollNo,S.studentName,Member2rollNo,S.studentName,sg.Member3rollNo,sg.supervID,sg.projectTitle
FROM student S
inner join studentGroup SG ON S.studentRollNo = SG.Member1rollNo
或者像這樣的一些隨機嘗試
-- Faculty.facultyName
SELECT FYP1.groupID, studentGroup.Member1rollNo,student.studentName as student1, studentGroup.Member2rollNo,student.studentName as student2,studentGroup.projectTitle
FROM FYP1 as FYP1_Students
INNER JOIN studentGroup ON (studentGroup.groupID = FYP1_Students.groupID)
INNER JOIN supervisors ON (studentGroup.supervID = supervisors.supervisorID)
INNER JOIN student ON (student1.studentRollNo = studentGroup.Member1rollNo)
INNER JOIN student ON (student.studentRollNo = studentGroup.Member2rollNo)
Output 或第一個查詢是這樣的(示例):
'i19-0434' 'Sourav Malani' 'i19-0498' 'Sourav Malani' NULL 'urooj.ghani' 'Indoor Navigation'
'i19-0466' 'Aftab Ali' 'i19-0528' 'Aftab Ali' NULL 'urooj.ghani' 'AI based Physics exp.'
我希望 output 是這樣的:
'i19-0434' 'Sourav Malani' 'i19-0498' 'Student2 Name' NULL 'urooj.ghani' 'Indoor Navigation'
'i19-0466' 'Aftab Ali' 'i19-0528' '<student2Name>' NULL 'urooj.ghani' 'AI based Physics exp.'
感謝@Hana,我解決了這個問題。 這是解決方案:
SELECT SG.groupID,
SG.Member1rollNo,S1.studentName as 'student1 Name',
SG.Member2rollNo, S2.studentName as 'student2 Name',
SG.Member3rollNo, S3.studentName as 'Studen3 Name',
SG.supervID, SN.facultyName as 'Supervisor Name',
SG.co_supervID, CSN.facultyName as 'Co_Supervisor',
SG.projectTitle as 'Project Title',
SG.projectDetails as 'Project Desc.'
FROM FYP1 FYP1
LEFT OUTER JOIN studentGroup SG ON FYP1.groupID = SG.groupID
LEFT OUTER JOIN supervisors SV ON SG.supervID = SV.supervisorID
LEFT OUTER JOIN Faculty SN ON SG.supervID= SN.facultyID
LEFT OUTER JOIN Faculty CSN ON SG.co_supervID= CSN.facultyID
LEFT OUTER JOIN student S1 ON SG.Member1rollNo = S1.studentRollNo
LEFT OUTER JOIN student S2 ON SG.Member2rollNo = S2.studentRollNo
LEFT OUTER JOIN student S3 ON SG.Member3rollNo = S3.studentRollNo
這是你想要的?
SELECT SG.groupID, SV.supervisorID, CSV.co_supervisorID, S1.studentName, S2.studentName, S3.studentName
FROM FYP1 FYP1
INNER JOIN studentGroup SG ON FYP1.groupID = SG.groupID
INNER JOIN supervisors SV ON SG.supervID = SV.supervisorID
INNER JOIN co_supervisors CSV ON SG.co_supervID = CSV.co_supervisorID
INNER JOIN student S1 ON SG.Member1rollNo = S1.studentRollNo
INNER JOIN student S2 ON SG.Member1rollNo = S2.studentRollNo
INNER JOIN student S3 ON SG.Member1rollNo = S3.studentRollNo
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