Mysql 当我们在表中只使用主题Id时,如何从表中选择主题名称
当我们在表中仅使用主题Id,并且使用另一个表主题主控形状时,如何从表中选择主题名称Mysql 当我们在表中只使用主题Id时,如何从表中选择主题名称,mysql,sql,sql-server,oracle,Mysql,Sql,Sql Server,Oracle,当我们在表中仅使用主题Id,并且使用另一个表主题主控形状时,如何从表中选择主题名称 Table StudentMaster -------------------------- StudentId int Unchecked StudentName varchar(50) Checked Subject1 int Checked Subject2 int Checked Subject3 int Checked Sample Record ----------------
Table StudentMaster
--------------------------
StudentId int Unchecked
StudentName varchar(50) Checked
Subject1 int Checked
Subject2 int Checked
Subject3 int Checked
Sample Record
------------------------------------
ID Name Subject1 Subject2 Subject3
1 Mohan 1 2 4
2 Sohan 3 2 5
3 Neha 5 1 2
Table Subject
-----------------------
SubjectId int Unchecked
SubjectName varchar(150) Checked
Sample Record
-----------------
SubjectId SubjectName
1 Hindi
2 English
3 Physics
4 Chemistry
5 Maths
如何获得Sohan、Mohan和Neha选择的主题
我想要这样的结果
StudentId StudentName Subject1 Subject2 Subject3
1 Mohan Hindi English Chemistry
2 Sohan Physics English Maths
3 Neha Maths Hindi English
试试这个:
SELECT
SM.StudentId,
SM.StudentName,
S1.SubjectName AS "Subject1",
S2.SubjectName AS "Subject2",
S3.SubjectName AS "Subject3"
FROM StudentMaster SM
LEFT JOIN Subject S1
S1.SubjectId = SM.Subject1
LEFT JOIN Subject S2
S2.SubjectId = SM.Subject2
LEFT JOIN Subject S3
S3.SubjectId = SM.Subject3
试试这个:
SELECT
SM.StudentId,
SM.StudentName,
S1.SubjectName AS "Subject1",
S2.SubjectName AS "Subject2",
S3.SubjectName AS "Subject3"
FROM StudentMaster SM
LEFT JOIN Subject S1
S1.SubjectId = SM.Subject1
LEFT JOIN Subject S2
S2.SubjectId = SM.Subject2
LEFT JOIN Subject S3
S3.SubjectId = SM.Subject3
您已经为三个不同的数据库标记了此问题。你到底在用哪一个?@Rajkumar Patro,如果我的帖子解决了你的问题,请将它标记为答案,这样问题就可以结束了。谢谢。您已经为三个不同的数据库标记了此问题。你到底在用哪一个?@Rajkumar Patro,如果我的帖子解决了你的问题,请将它标记为答案,这样问题就可以结束了。谢谢