Question

MaingroupTable

MubGroupCodeid       MainName      maincode
1                     Health          098
2                     Social          078

子组表

SubGroupCodeid     SubName         subcode

1                  Nursing          211
2                  Civics           224

SubandMainGroup 表

subandmainid      **MubGroupCodeid**       **subgroupcodeid**       
1                    1                      1         
2                    2                       2

学生桌

studid   studname      **subandmainid** (foriegn key of **subandmain group**  table)
1       Alex            1  
2       siraj           2

然后我想加入并合并studname-maingroupcode-subgroupcode以获得如下所示的输出

  Alex-098-211 
  siraj-078-224

Answer 1

这将帮助您入门并解释联接。您可能还想对主代码和子代码进行一些转换，但是由于不是100％清楚，它们还不是varchar值，因此我忽略了这一点。

Answer 2

使用连接并通过||

合并所有必需的列

select s.studname ||'-'||subG.subcode ||'-' M.maincode
                from 
               Student s join SubandMainGroup  subM on s.subandmainid=subM.subandmainid      
                 join SubGroup subG on subG.SubGroupCodeid=subM.subgroupcodeid
                 join MaingroupTable M on M.MubGroupCodeid=subM.MubGroupCodeid

Answer 3

使用以下查询解决问题。

select stu.studname + '-'+mgrp.maincode +'-'+sgrp.subcode from Student_ stu 
join Maingroup mgrp on stu.studid=mgrp.MubGroupCodeid 
join SubGroup sgrp on sgrp.SubGroupCodeid=stu.studid

在mssql中加入四个表

3 个答案: