Using different set of WHERE clauses in stored procedure depending on Parameter value - sql

Question

I have 2 stored procedures which return the same columns that I am trying to merge into a single procedure. They both have a different set of parameters and both have different WHERE clauses, but they use the same tables and select the exact same rows.
WHERE clause 1: (uses #UIOID, and #Level)
WHERE ( #UIOID = CASE WHEN #Level = 'Single' THEN C.C_UIOID_PK
WHEN #Level = 'Children' THEN CLC.UIOL_P
WHEN #Level = 'Parent' THEN CLP.UIOL_C
END
OR ( #UIOID = '0'
AND #Level = 'All'
)
)
Where clause 2: (Uses #TeamCode, #Year, #IncludeQCodes)
WHERE C.C_IsChild = 0
AND C.C_MOA <> 'ADD'
AND #TeamCode = C.C_OffOrg
AND C.C_Active = 'Y'
AND ( #Year BETWEEN dbo.f_GetAcYearByDate(C.C_StartDate) AND dbo.f_GetAcYearByDate(C.C_EndDate)
OR #Year = 0 )
AND ( C.C_InstCode NOT LIKE 'Q%'
OR #IncludeQCodes = 1 )
Ideally I want to add a new parameter which basically tells it which of the two WHERE clauses to run, but I can't seem to recreate that with CASE statement because as far as I can tell, they only work for a single WHERE clause, not a whole set of different clauses
I want to do this without having to repeat the select statement again and putting the whole thing in IF statements, and i don't want to put the query into a string either. I just want one select statement ideally.
The problem with using temp tables is the query itself takes a while to run without any parameters and is used in a live website, so I don't want it to have to put all records in a temp table and then filter it.
The problem with using a CTE is you can't follow it with an IF statement, so that wouldn't work either.
Here is the sort of logic I am trying to achieve:
SELECT A
B
C
FROM X
IF #WhichOption = 1 THEN
WHERE ( #UIOID = CASE WHEN #Level = 'Single' THEN C.C_UIOID_PK
WHEN #Level = 'Children' THEN CLC.UIOL_P
WHEN #Level = 'Parent' THEN CLP.UIOL_C
END
OR ( #UIOID = '0'
AND #Level = 'All'
)
)
ELSE IF #WhichOption = 2 THEN
WHERE C.C_IsChild = 0
AND C.C_MOA <> 'ADD'
AND #TeamCode = C.C_OffOrg
AND C.C_Active = 'Y'
AND ( #Year BETWEEN dbo.f_GetAcYearByDate(C.C_StartDate) AND dbo.f_GetAcYearByDate(C.C_EndDate)
OR #Year = 0 )
AND ( C.C_InstCode NOT LIKE 'Q%'
OR #IncludeQCodes = 1 )

Answer 1

Save the following process in a procedure. You can also directly insert into a physical table.
declare #varTable Table (columns exactly as Procedures return)
if(condition is met)
begin
insert into #varTable
exec proc1
end
else
begin
insert into #varTable
exec proc2
end

Answer 2

Add the parameter that you said that it would indicate what filter apply :
select XXXXX
from XXXXX
where (#Mode = 1 and ( filter 1 ))
or
(#Mode = 2 and ( filter 2 ))
option(recompile)
If the #Mode parameter is 1 then it will evaluate the filter 1, otherwise it will evaluate the filter 2.
Add an option(recompile) at the end of the statement, so the SQL engine will replace the variables with their values, eliminate the filter that won't be evaluated, and generate an execution plant for just the filter that you want to apply.
PS: Please notice that although these catchall queries are very easy to code and maintain, and generate a perfectly functional and optimal execution, they are not advised for high-demand applications. The option(recompile) forces the engine to recompile and generate a new execution plan at every execution and that would have a noticeable effect on performance if your query needs to be executed hundreds of times per minute. But for the occasional use it's perfectly fine.

Answer 3

Try to use dynamic SQL:
DECLARE #sql NVARCHAR(max), #where NVARCHAR(max), #WhichOption INT = 1;
SET #sql = 'SELECT A
B
C
FROM X';
IF #WhichOption = 1
SET #where = 'WHERE ( #UIOID = CASE WHEN #Level = ''Single'' THEN C.C_UIOID_PK
WHEN #Level = ''Children'' THEN CLC.UIOL_P
WHEN #Level = ''Parent'' THEN CLP.UIOL_C
END
OR ( #UIOID = ''0''
AND #Level = ''All''
)
)';
ELSE IF #WhichOption = 2
SET #where = ' WHERE C.C_IsChild = 0
AND C.C_MOA <> ''ADD''
AND #TeamCode = C.C_OffOrg
AND C.C_Active = ''Y''
AND ( #Year BETWEEN dbo.f_GetAcYearByDate(C.C_StartDate)
AND dbo.f_GetAcYearByDate(C.C_EndDate)
OR #Year = 0 )
AND ( C.C_InstCode NOT LIKE ''Q%''
OR #IncludeQCodes = 1 ) ';
SET #sql = CONCAT(#sql,' ', #where)
PRINT #sql
EXECUTE sp_executesql #sql