Where Clause Using Conditional Statement - sql

Question

i have query below
SELECT #RoleUser = MR.Code FROM MasterRole MR INNER JOIN MasterUsersRole MUR ON MR.Id = MUR.RoleId
INNER JOIN MasterUsers MU ON Mu.UserCode = MUR.UserCode
WHERE MU.UserCode = #UserLoginID
select 1 Num
, MyHistory.ID
, MyHistory.RequestNumber
, MyHistory.FlowID
, MyHistory.FlowProcessStatusID
from
(
select *
from Requests R
inner join
(
--DECLARE #UserLoginID nvarchar(200) = 'dum.testing.3'
select distinct
RequestID
from dbo.RequestTrackingHistory RTH
where IIF(#UserLoginID = 'admin', #UserLoginID, RTH.CreatedBy) = #UserLoginID
OR ( CreatedBy IN
SELECT Mu.UserCode from MasterUsers MU
INNER JOIN MasterUsersRole MUR ON MU.UserCode = MUR.UserCode
INNER JOIN MasterRole MR ON MUR.RoleId = MR.Id
WHERE MR.Code = #RoleUser
)
)
) RT on R.ID = RT.RequestID
) as MyHistory
inner join MasterFlow F on MyHistory.FlowID = F.ID
inner join
(
select FP.ID
, FP.Name
, FP.AssignType
, FP.AssignTo
, FP.IsStart
, case FP.AssignType
when 'GROUP' then
G.Name
end as 'AssignToName'
from MasterFlowProcess FP
left join dbo.MasterRole G on FP.AssignTo = G.ID and FP.AssignType = 'GROUP'
) FP on MyHistory.FlowProcessID = FP.ID
inner join MasterFlowProcessStatus FPS on MyHistory.FlowProcessStatusID = FPS.ID
left join MasterFlowProcessStatusNext FPSN on FPS.ID = FPSN.ProcessStatusFlowID
left join MasterFlowProcess FPN on FPSN.NextProcessFlowID = FPN.ID
left JOIN MasterRole MR ON MR.Id = FPN.AssignTo
left join MasterUsersRole MUR on MR.Id = MUR.RoleId
left join MasterUsers MURO on MUR.UserCode = MURO.UserCode
inner join MasterUsers UC on MyHistory.CreatedBy = UC.UserCode
left join MasterUsers UU on MyHistory.UpdatedBy = UU.UserCode
LEFT JOIN RequestMT RMT ON MyHistory.ID = RMT.RequestID
LEFT JOIN RequestGT RGT ON MyHistory.ID = RGT.RequestID
left join (SELECT sum(QtyCU) countQty , RequestId from dbo.RequestGTDetail where IsActive = 1 group by RequestId) RGTD on RGTD.RequestId = RGT.RequestId
left join (SELECT sum(QtyPCS) countQty , RequestId from dbo.RequestMTDetail where IsActive = 1 group by RequestId) RMTD on RMTD.RequestId = RMT.RequestId
left join (SELECT COUNT(IIF(returnable = 0, returnable, null)) countReturnable , RequestId from dbo.RequestMTDetail group by RequestId) RMTR on RMTR.RequestId = RMT.RequestId
left JOIN dbo.MasterDistributor md ON md.Code = RGT.CustId or md.Code = RMT.CustId
left JOIN dbo.MasterUsersDistributor MUD ON MUD.UserCode = MURO.UserCode AND md.Code = MUD.DistributorCode
LEFT JOIN dbo.MasterReason MRMT ON RMT.ReasonId = MRMT.Id
LEFT JOIN dbo.MasterReason MRGT ON RGT.ReasonId = MRGT.Id
LEFT JOIN dbo.MasterDistributorGroup MDG ON MDG.Id = MD.GroupId
OUTER APPLY dbo.FnGetHistoryApproveDate(MyHistory.Id) AS x
where REPLACE(FPS.Name, '#Requestor', uc.Name) <> 'DRAFT'
AND MUD.DistributorCode IN (SELECT DistributorCode FROM dbo.MasterUsersDistributor WHERE UserCode = #UserLoginID)
i want to add some logic in where clause
this line
==> AND MUD.DistributorCode IN (SELECT DistributorCode FROM dbo.MasterUsersDistributor WHERE UserCode = #UserLoginID)
it depend on the #RoleUser variable, if #RoleUser IN ('A','B') then where clause above is executed, but if #RoleUser Not IN ('A','B') where clause not executed
i,m trying this where clause
AND IIF(#RoleUser IN ('A','B'), MUD.DistributorCode, #RoleUser) IN (SELECT DistributorCode FROM dbo.MasterUsersDistributor WHERE UserCode = IIF(#RoleUser IN ('A','B'), #UserLoginID, NULL))
it didn't work, only executed if #RoleUser IS ('A','B') other than that it return 0 record
any help or advice is really appreciated
thank you

Answer 1

The cleanest way I'm implemented these kind of crazy rules is a
holderTable
and a countVariable against the holder table.
I'll give a generic examples.
This is a "approach" and "philosophy", not a specific answer....with complex WHERE clauses.
DECLARE #customerCountryCount int
DECLARE #customerCountry TABLE ( CountryName varchar(15) )
if ( "the moon is blue on tuesday" ) /* << whatever rules you have */
BEGIN
INSERT INTO #customerCountry SELECT "Honduras" UNION ALL SELECT "Malaysia"
END
if ( "favorite color = green" ) /* << whatever rules you have */
BEGIN
INSERT INTO #customerCountry SELECT "Greenland" UNION ALL SELECT "Peru"
END
SELECT #customerCountryCount = COUNT(*) FROM #customerCountry
Select * from dbo.Customers c
WHERE
(#customerCountryCount = 0)
OR
( exists (select null from #customerCountry innerVariableTable where UPPER(innerVariableTable.CountryName) = UPPER(c.Country) ))
)
This way, instead of putting all the "twisted logic" in an overly complex WHERE statement..... you have "separation of concerns"...
Your inserts into #customerCountry are separated from your use of #customerCountry.
And you have the #customerCountryCount "trick" to distinguish when nothing was used.
You can add a #customerCountryNotExists table as well, and code it to where not exists.
As a side note, you may want to try using a #temp table (instead of a #variabletable (#customerCountry above)... and performance test these 2 options.
There is no "single answer". You have to "try it out".
And many many variables go into #temp table performance (from a sql-server SETUP, not "how you code a stored procedure". That is way outside the scope of this question.
Here is a SOF link to "safe" #temp table usage.
Temporary table in SQL server causing ' There is already an object named' error