在SQL中使用join进行多次和

Question

This is Rudresh BR, Trying to obtain data of same rows into multiple columns also by doing sum. But stuck with an issue, Please find the below mentioned details regarding the issue,

Expected Data:

But obtained Data:

Data Existing in Table

1. List item

Query used:

select 
    a.BM_BANK_NAME,
    SUM(PCBunit.BID_CURRENCY_VALUE) as PCBUnitSum,
     SUM(PTBunit.BID_CURRENCY_VALUE) as PTBUnitSum  
from 
     dbo.BG_Mtr_Bank_Master a 
     inner join dbo.BG_Tra_Issuance_Details PCBunit on a.BM_ID=PCBunit.BID_BANK_NAME and PCBunit.BID_UNIT_DIVISION='PCB' 
     inner join dbo.BG_Tra_Issuance_Details PTBunit on a.BM_ID=PTBunit.BID_BANK_NAME and PTBunit.BID_UNIT_DIVISION='PTB' 
group by 
     a.BM_BANK_NAME,
     PCBunit.BID_UNIT_DIVISION,
     PTBunit.BID_UNIT_DIVISION

PCBUnitSum and PTBUnitSum is the sum of rows of BID_Currency_Value of PCB and PTB respectively.

What I am observing is once the sum is done ie 3000(which i am expecting as output) , it's redoing the sum based on number of rows PCB and PTB exists respectively, so as there are 3 rows of PCB, 3000+3000+3000=9000 is given as O/P.

I request everyone to, Please help me out to find what's going wrong?

Answer 1

Do not self-join the table, use case

select a.BM_BANK_NAME
     , SUM(case when t.BID_UNIT_DIVISION ='PCB' then t.BID_CURRENCY_VALUE end) as PCBUnitSum
     , SUM(case when t.BID_UNIT_DIVISION ='PTB' then t.BID_CURRENCY_VALUE end) as PTBUnitSum  
  from dbo.BG_Mtr_Bank_Master a 
 inner 
  join dbo.BG_Tra_Issuance_Details t 
    on a.BM_ID = t.BID_BANK_NAME 
   and t.BID_UNIT_DIVISION in ('PCB', 'PTB')
 group  
    by a.BM_BANK_NAME

Answer 2

Try this:

DECLARE @list_item TABLE ( unit NVARCHAR(5),bank NVARCHAR(5),curr INT)
INSERT INTO @list_item VALUES ('PCB','SBI',1000),('PCB','SBI',1000),
('PCB','SBI',1000),('PTB','SBI',1000),('PTB','SBI',1000),
('PTB','SBI',1000)

SELECT bank,
SUM(CASE WHEN unit='PCB' THEN curr END) PCBUnitSum,
SUM(CASE WHEN unit='PTB' THEN curr END) PTBUnitSum
FROM ( SELECT unit,bank,SUM(curr)curr FROM @list_item 
group by unit,bank ) A GROUP BY bank

This might help. :)