Use Multiple conditions in Case Statement - sql

Question

I have implemented multiple conditions in case statement as below,
select officied from budgettable
where budgetid = case #budgetid when 7 then 7
when 7 then 8
when 7 then 10
when 8 then 6
end
but it didn't give me any result. If I pass budget-Id as 7 the query should return 8,10,7 budget id's. Anything wrong in the above query?

Answer 1

I suspect that you want something like this:
where budgetid = #budgetid or
(#budgetid = 7 and budgetid in (7, 8, 10)) or
(#budgetid = 8 and budgetid = 6)
Your query is failing because for all values of #budgetid other than 7 or 8, the case returns NULL -- which is treated as false.

Answer 2

One option is to use the case as a boolean expression, returning 1 when your conditions are met:
select officied from budgettable
where 1 = case
when #budgetid = budgetid then 1
when #budgetid = 7 and budgetid in (7,8,10) then 1
when #budgetid = 8 and budgetid in (6,8) then 1
end
This expands the results returned by #budgetid 7 to include 8 and 10.

Answer 3

This is no answer. I just want to show how CASE WHEN works, so you see your mistake. Your query evaluates case #budgetidas follows:
when 7 then 7 => take a 7 for a #budgetid 7
when 7 then 8 => ignored, because we already said to take 7 for a #budgetid 7
when 7 then 10 => ignored, because we already said to take 7 for a #budgetid 7
when 8 then 6 => take a 6 for a #budgetid 8
end => no else here, so any other #budgetid results in NULL.
You then compare the result with = budgetid. This is never true for NULL. So you end up with:
where (#budgetid = 7 and budgetid = 7)
or (#budgetid = 8 and budgetid = 6)

Answer 4

This will work !!
SELECT
officied
FROM
budgettable
WHERE
1 = 1
AND
1 = CASE
WHEN
#budgetid = budgetid THEN 1
WHEN
(#budgetid = 7 AND budgetid IN (7,8,10)) THEN 1
WHEN
(#budgetid = 8 AND budgetid IN (6,8) THEN) 1
END
Better solution : Add a new column is_budget_calculated (Data type BIT) and update it as 0 and remaining as 1.