Please help me with this database query [closed] - sql

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Closed 10 years ago.
I have table xyz, and I have 13 columns namely emplid, jan,feb… dec.
here I have data as below
EMPLID JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
123 0 0 0 0 0 5 5 2 6 0 0 0
456 0 2 3 0 0 0 5 5 3 0 0 0
789 5 0 0 5 0 5 0 5 6 3 0 4
ABC 4 5 0 5 5 0 5 0 6 0 0 0
Now I need to write a query so that I get the output as the very first month for which some data is entered other than 0
For eg : if I check for EMPLID 123, I should get output as JUN (because JUN is the very first month for this EMPLID where data is other than 0)
Similarly for 456, it would be FEB, for 789 and ABC its JAN.

Answer 1

As Philipp says in his comment, your table structure is definitely to be changed. Other wise you will run into lots of issues like this in future..
To answer your question, you could try this:
select case when JAN > 0 then 'JAN'
when FEB > 0 then 'FEB'
when MAR > 0 then 'MAR'
when APR > 0 then 'APR'
when MAY > 0 then 'MAY'
when JUN > 0 then 'JUN'
when JUL > 0 then 'JUL'
when AUG > 0 then 'AUG'
when SEP > 0 then 'SEP'
when OCT > 0 then 'OCT'
when NOV > 0 then 'NOV'
when DEC > 0 then 'DEC'
end as Month
from xyz
where EMPLID='456'
SQL Fiddle demo

Answer 2

First of all I recommend to refactor like Philipp mentioned:
Use one table like this:
EMPLID MONTH VALUE
123 1 3
123 12 5
In this case its more easy to query:
SELECT [MONTH]
FROM YourTable
GROUP BY EMPLID, [MONTH]
HAVING VALUE > 0
AND MIN([MONTH]) = [MONTH]
If you don't have another choise use a case:
SELECT
CASE
WHEN JAN > 0 THEN 'JAN'
WHEN FEB > 0 THEN 'FEB'
WHEN MAR > 0 THEN 'MAR'
WHEN APR > 0 THEN 'APR'
WHEN MAY > 0 THEN 'MAY'
WHEN JUN > 0 THEN 'JUN'
WHEN JUL > 0 THEN 'JUL'
WHEN AUG > 0 THEN 'AUG'
WHEN SEP > 0 THEN 'SEP'
WHEN OCT > 0 THEN 'OCT'
WHEN NOV > 0 THEN 'NOV'
WHEN DEC > 0 THEN 'DEC'
ELSE 'No Month found'
END AS FirstMonth
FROM YourTable

Answer 3

As Philipp said, it's better to use a different structure for your table.
Working with the current structure you can do something like this:
Select a.EMPLID, case when (select b.JAN from tbl b where a.EMPLID=b.EMPLID) > 0 then 'JAN'
when.....etc(the same for each month).... end as Val
from tbl a
Probably this isn't the best solution but it should work.