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Require help in DB2 Query


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Shruti Takkar

New User


Joined: 09 Apr 2015
Posts: 5
Location: india

PostPosted: Wed Aug 03, 2016 10:57 pm
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Hi ,

I have to execute below problem in DB2 query, please suggest some valuable options.

Consider Table A having account details.
I need to count accounts from Table A for multiple scenarios.

I can count accounts using multiple case when conditions like below.
===========================================
select Count(case when t1.a = 1 then 1 else 0 end) as A_COUNT
, Count(case when t1.b = 2 then 1 else 0 end) as B_COUNT
from t1
============================================

My problem here is,, if my account is counted in A_COUNT, it should not get double counted in B_COUNT.

There are multiple when conditions and it is not possible to tweak them to make all conditions mutually exclusive.

Regards,
Shruti
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Rohit Umarjikar

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Joined: 21 Sep 2010
Posts: 2569
Location: NYC,USA

PostPosted: Wed Aug 03, 2016 11:27 pm
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you will have to explain better. tell us the input table and sample values and expected output and then it goes easy for anyone to provide you a solution. why do you not do group by on account number and those t1.a,t1.b and so on?
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chandan.inst

Active User


Joined: 03 Nov 2005
Posts: 275
Location: Mumbai

PostPosted: Tue Aug 09, 2016 11:20 am
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is this something you are expecting?

Code:
select
Count(case when (t1.a = 1 and t1.b<> 2) then 1 else 0 end) as A_COUNT
, Count(case when (t1.b = 2 and t1.a<>1) then 1 else 0 end) as B_COUNT
from t1


Thanks,
Chandan
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Rohit Umarjikar

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Joined: 21 Sep 2010
Posts: 2569
Location: NYC,USA

PostPosted: Wed Aug 10, 2016 12:06 am
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Code:
Select innr.type,sum(innr.cnt )
from
(select
    case  when t1.a = 1 then 1 else 0
            when t1.b = 2  then 1 else 0 end  as cnt
    ,case when t1.a = 1 then 'A'
            when t1.b = 2  then 'B' end as type
from table temp; ) as innr
group by innr.type
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