加入3个或更多表格并总结这些字段

Question

我想加入3个表格。

结果是场之一 - 从另一个表这样的形象SUM，请帮助

Answer 1

你并不需要加入tblwork，你可以得到从其他2所有必填字段表。

以下查询应该工作：

select t1.nmstudent, 
      sum(case when t2.idwork = 'w001' then t2.trprice else 0 end) as w001, 
      sum(case when t2.idwork = 'w002' then t2.trprice else 0 end) as w002, 
      sum(case when t2.idwork = 'w003' then t2.trprice else 0 end) as w003, 
      sum(case when t2.idwork = 'w004' then t2.trprice else 0 end) as w004 
    from tblstudent t1 
    inner join tblTrans t2 
    on t1.idstudent = t2.idstudent 
    group by t1.idstudent; 

希望它能帮助！