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T-SQL CASE Statement

Posted on 2014-01-02
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Last Modified: 2014-01-02
Hello:

Below is a select statement pulling fields of data from another select statement.  The "Month" field is formatted and returned as "Month 01", "Month 02", "Month 03", etc. through "Month 18".

When I run this statement against our data, some months legitimately do not appear.  Month 02 is an example.  There are no purchase orders for that month and, therefore, it does not show when selected.

But, I would like to show fields of data for Month 02 and any other "missing months".

So, I would like to have a single line of data representing Month 02 but have all other fields for that line be blank or 0.

How can I accomplish this?

Truthfully, I started with the second "big" select statement.  When I could not find a way to add missing months in it, I "added" the first select statement that is wrapped around the select case statement.  (I hope that makes sense.)

Thanks!

TBSupport



select
ContractNum, VENDORID, StartDate, EndDate, Month, ITEMNMBR, ITEMDESC, AvailQuantity, EXTDCOST
 FROM(
select RCG.dbo.POContractHeader.ContractNum, RCG.dbo.POContractHeader.VENDORID, RCG.dbo.POContractHeader.StartDate, RCG.dbo.POContractHeader.EndDate,
'Month ' +
CASE WHEN DATEDIFF(m,GETDATE(),RCG.dbo.POContractHeader.EndDate) + 1 < 10
THEN CAST(CAST('0' AS VARCHAR) + CAST(DATEDIFF(m,GETDATE(),RCG.dbo.POContractHeader.EndDate) + 1 AS VARCHAR(1)) AS VARCHAR(2))
ELSE CAST(DATEDIFF(m,GETDATE(), RCG.dbo.POContractHeader.EndDate) + 1 AS VARCHAR(2))
END
AS Month,
--RCG.dbo.PODraws.PONUMBER,
RCG.dbo.POContractDetail.ITEMNMBR, RCG.dbo.POContractDetail.ITEMDESC, RCG.dbo.POContractDetail.AvailQuantity, RCG.dbo.POContractDetail.EXTDCOST
from RCG.dbo.POContractHeader
INNER JOIN RCG.dbo.POContractDetail on RCG.dbo.POContractHeader.ContractNum = RCG.dbo.POContractDetail.ContractNum
and RCG.dbo.POContractHeader.VENDORID = RCG.dbo.POContractDetail.VENDORID
INNER JOIN RCG.dbo.PODraws on RCG.dbo.POContractDetail.ContractNum = RCG.dbo.PODraws.ContractNum
and RCG.dbo.POContractDetail.VENDORID = RCG.dbo.PODraws.VENDORID
where RCG.dbo.POContractHeader.StartDate IS NOT NULL and RCG.dbo.POContractHeader.EndDate IS NOT NULL
and RCG.dbo.POContractDetail.AvailQuantity <> 0
and (RCG.dbo.POContractHeader.EndDate >= DATEADD(m, DATEDIFF(m, 0, GETDATE()), 0)) AND
(RCG.dbo.POContractHeader.EndDate < DATEADD(m, DATEDIFF(m, 0, GETDATE()) + 18, 0))
and RCG.dbo.POContractHeader.VENDORID = '8000028'
GROUP BY RCG.dbo.POContractHeader.VENDORID,
RCG.dbo.POContractHeader.ContractNum,
RCG.dbo.POContractHeader.StartDate, RCG.dbo.POContractHeader.EndDate,
RCG.dbo.POContractDetail.ITEMNMBR, RCG.dbo.POContractDetail.ITEMDESC, RCG.dbo.POContractDetail.AvailQuantity, RCG.dbo.POContractDetail.EXTDCOST--,
--RCG.dbo.PODraws.PONUMBER,
) as test
--ORDER BY RCG.dbo.POContractHeader.VENDORID, RCG.dbo.POContractHeader.EndDate
0
Comment
Question by:TBSupport
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6 Comments
 
LVL 25

Accepted Solution

by:
chaau earned 500 total points
ID: 39752491
You need to create a simple recursive CTE for the numbers 1 to 18, like this:
;with numbers as(
  SELECT 1 as N
  UNION ALL 
  SELECT numbers.N + 1
  FROM numbers
  WHERE N < 18)
-- your normal select goes here, below is an example
SELECT * FROM numbers

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Or, if above is too confusing, you can use UNION ALL, like this:
;with numbers as(
SELECT 1 as N
UNION ALL
SELECT 2 as N
UNION ALL
SELECT 3 as N
UNION ALL
SELECT 4 as N
UNION ALL
SELECT 5 as N
-- and so on
)

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Or, if the above statement seems to be too bulky, use
;with numbers as(
SELECT TOP 18 row_number() over(order by number) as N FROM master..spt_values
)

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And now all you need to do is to left-join the numbers cte with your existing query, like this:
;with numbers as(
-- put here any cte from the above, e.g.
SELECT TOP 18 row_number() over(order by number) as N FROM master..spt_values
),
months AS(
  SELECT 'Month ' + REPLACE(STR(N, 2), ' ', '0') AS Month
  FROM numbers)
select 
ContractNum, VENDORID, StartDate, EndDate, m.Month, ITEMNMBR, ITEMDESC, AvailQuantity, EXTDCOST
FROM months M LEFT JOIN
 (
select RCG.dbo.POContractHeader.ContractNum, RCG.dbo.POContractHeader.VENDORID, RCG.dbo.POContractHeader.StartDate, RCG.dbo.POContractHeader.EndDate,
'Month ' + REPLACE(STR(DATEDIFF(m,GETDATE(), RCG.dbo.POContractHeader.EndDate) + 1, 2), ' ', '0') AS Month,
--RCG.dbo.PODraws.PONUMBER,
RCG.dbo.POContractDetail.ITEMNMBR, RCG.dbo.POContractDetail.ITEMDESC, RCG.dbo.POContractDetail.AvailQuantity, RCG.dbo.POContractDetail.EXTDCOST
from RCG.dbo.POContractHeader
INNER JOIN RCG.dbo.POContractDetail on RCG.dbo.POContractHeader.ContractNum = RCG.dbo.POContractDetail.ContractNum
and RCG.dbo.POContractHeader.VENDORID = RCG.dbo.POContractDetail.VENDORID
INNER JOIN RCG.dbo.PODraws on RCG.dbo.POContractDetail.ContractNum = RCG.dbo.PODraws.ContractNum
and RCG.dbo.POContractDetail.VENDORID = RCG.dbo.PODraws.VENDORID
where RCG.dbo.POContractHeader.StartDate IS NOT NULL and RCG.dbo.POContractHeader.EndDate IS NOT NULL
and RCG.dbo.POContractDetail.AvailQuantity <> 0
and (RCG.dbo.POContractHeader.EndDate >= DATEADD(m, DATEDIFF(m, 0, GETDATE()), 0)) AND
(RCG.dbo.POContractHeader.EndDate < DATEADD(m, DATEDIFF(m, 0, GETDATE()) + 18, 0))
and RCG.dbo.POContractHeader.VENDORID = '8000028'
GROUP BY RCG.dbo.POContractHeader.VENDORID,
RCG.dbo.POContractHeader.ContractNum,
RCG.dbo.POContractHeader.StartDate, RCG.dbo.POContractHeader.EndDate,
RCG.dbo.POContractDetail.ITEMNMBR, RCG.dbo.POContractDetail.ITEMDESC, RCG.dbo.POContractDetail.AvailQuantity, RCG.dbo.POContractDetail.EXTDCOST--,
--RCG.dbo.PODraws.PONUMBER,
) as test ON m.Month = test.Month

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BTW, have you noticed that your case When < 10 can be replaced with a simpler version REPLACE(STR(N, 2), ' ', '0')
0
 
LVL 41

Expert Comment

by:Sharath
ID: 39752531
If you have months from 01 to 18, you can hardcode them like this in a sub-query and LEFT JOIN your actual query.
SELECT ContractNum, 
       VENDORID, 
       StartDate, 
       EndDate, 
       t1.[Month], 
       ITEMNMBR, 
       ITEMDESC, 
       AvailQuantity, 
       EXTDCOST 
  FROM (SELECT 'Month01' [Month] 
        UNION ALL 
        SELECT 'Month02' 
        UNION ALL 
        SELECT 'Month03' 
        UNION ALL 
        SELECT 'Month04' 
        UNION ALL 
        SELECT 'Month05' 
        UNION ALL 
        SELECT 'Month06' 
        UNION ALL 
        SELECT 'Month07' 
        UNION ALL 
        SELECT 'Month08' 
        UNION ALL 
        SELECT 'Month09' 
        UNION ALL 
        SELECT 'Month10' 
        UNION ALL 
        SELECT 'Month11' 
        UNION ALL 
        SELECT 'Month12' 
        UNION ALL 
        SELECT 'Month13' 
        UNION ALL 
        SELECT 'Month14' 
        UNION ALL 
        SELECT 'Month15' 
        UNION ALL 
        SELECT 'Month16' 
        UNION ALL 
        SELECT 'Month17' 
        UNION ALL 
        SELECT 'Month18') t1 
       LEFT JOIN (SELECT RCG.DBO.POContractHeader.ContractNum, 
                         RCG.DBO.POContractHeader.VENDORID, 
                         RCG.DBO.POContractHeader.StartDate, 
                         RCG.DBO.POContractHeader.EndDate, 
                         'Month ' + CASE WHEN DATEDIFF(M, GETDATE(), RCG.DBO.POContractHeader.EndDate) + 1 < 10 THEN CAST(CAST('0' AS VARCHAR) + CAST(DATEDIFF(M, GETDATE(), RCG.DBO.POContractHeader.EndDate) + 1 AS VARCHAR(1)) AS VARCHAR(2)) ELSE CAST(DATEDIFF(M, GETDATE(), RCG.DBO.POContractHeader.EndDate) + 1 AS VARCHAR(2)) END AS [Month],
                         --RCG.dbo.PODraws.PONUMBER,  
                         RCG.DBO.POContractDetail.ITEMNMBR, 
                         RCG.DBO.POContractDetail.ITEMDESC, 
                         RCG.DBO.POContractDetail.AvailQuantity, 
                         RCG.DBO.POContractDetail.EXTDCOST 
                    FROM RCG.DBO.POContractHeader 
                         INNER JOIN RCG.DBO.POContractDetail 
                                 ON RCG.DBO.POContractHeader.ContractNum = RCG.DBO.POContractDetail.ContractNum
                                    AND RCG.DBO.POContractHeader.VENDORID = RCG.DBO.POContractDetail.VENDORID
                         INNER JOIN RCG.DBO.PODraws 
                                 ON RCG.DBO.POContractDetail.ContractNum = RCG.DBO.PODraws.ContractNum
                                    AND RCG.DBO.POContractDetail.VENDORID = RCG.DBO.PODraws.VENDORID
                   WHERE RCG.DBO.POContractHeader.StartDate IS NOT NULL 
                     AND RCG.DBO.POContractHeader.EndDate IS NOT NULL 
                     AND RCG.DBO.POContractDetail.AvailQuantity <> 0 
                     AND ( RCG.DBO.POContractHeader.EndDate >= DATEADD(M, DATEDIFF(M, 0, GETDATE()), 0) )
                     AND ( RCG.DBO.POContractHeader.EndDate < DATEADD(M, DATEDIFF(M, 0, GETDATE()) + 18, 0) )
                     AND RCG.DBO.POContractHeader.VENDORID = '8000028' 
                   GROUP BY RCG.DBO.POContractHeader.VENDORID, 
                            RCG.DBO.POContractHeader.ContractNum, 
                            RCG.DBO.POContractHeader.StartDate, 
                            RCG.DBO.POContractHeader.EndDate, 
                            RCG.DBO.POContractDetail.ITEMNMBR, 
                            RCG.DBO.POContractDetail.ITEMDESC, 
                            RCG.DBO.POContractDetail.AvailQuantity, 
                            RCG.DBO.POContractDetail.EXTDCOST--,  
                 --RCG.dbo.PODraws.PONUMBER,  
                 ) AS test 
              ON t1.[Month] = t2.[Month] 
--ORDER BY RCG.dbo.POContractHeader.VENDORID, RCG.dbo.POContractHeader.EndDate

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0
 
LVL 1

Author Comment

by:TBSupport
ID: 39752568
Thanks, All, for the responses!

Sharath_123>> I think that your "[Month]" is out of place.  Can you check, again, and update the case?  

Also, where is "t2"?

TBSupport
0
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LVL 1

Author Comment

by:TBSupport
ID: 39752583
chaau>>Your solution works really well!  Thank you!  Question:  Is there a way for me to get the EXTDCOST to return "0" instead of "NULL"?
0
 
LVL 25

Expert Comment

by:chaau
ID: 39752607
Sure, use ISNULL(), like this:
.....
select 
ContractNum, VENDORID, StartDate, EndDate, m.Month, ITEMNMBR, ITEMDESC, AvailQuantity, ISNULL(EXTDCOST,0) AS EXTDCOST
......

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0
 
LVL 41

Expert Comment

by:Sharath
ID: 39752619
>>  I think that your "[Month]" is out of place.
What do you mean?

>> Also, where is "t2"?
replace t2 with test.
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