Question

当我们在表中仅使用主题ID时，如何从表中选择主题名称，我们正在使用另一个表主题。

<properties>
    <cucumber-version>1.2.4</cucumber-version>
    <junit-version>1.2.4</junit-version>
</properties>

<dependencies>
    <dependency>
        <groupId>info.cukes</groupId>
        <artifactId>cucumber-java</artifactId>
        <version>{junit-version}</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>info.cukes</groupId>
        <artifactId>cucumber-junit</artifactId>
        <version>{junit-version}</version>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-surefire-plugin</artifactId>
        <version>2.12.2</version>
        <configuration>
            <argLine>-Duser.language=en</argLine>
            <argLine>-Xmx1024m</argLine>
            <argLine>-XX:MaxPermSize=256m</argLine>
            <argLine>-Dfile.encoding=UTF-8</argLine>
            <useFile>false</useFile>
        </configuration>
        </plugin>
    </plugins>
</build>

如何获得Sohan，Mohan和Neha选择的主题???

我希望结果像

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

Answer 1

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

Answer 2

SELECT 
S.StudentId, 
S.StudentName,
S1.SubjectName AS Subject1,
S2.SubjectName AS Subject2,
S3.SubjectName AS Subject3
FROM StudentMaster S
LEFT OUTER JOIN Subject S1
S1.SubjectId = S.Subject1
LEFT OUTER JOIN Subject S2
S2.SubjectId = S.Subject2
LEFT OUTER JOIN Subject S3
S3.SubjectId = S.Subject3
ORDER BY S.StudentId

当我们在表中仅使用主题ID时，如何从表中选择主题名称

2 个答案: