SQL NOT exists conditional - sql

Question

I have three tables as described below:
dbo.ServiceEntry
ID RunLogEntry Reconciled
1 0 1
2 4 1
3 5 1
dbo.ServiceEntryPart
ID ServiceEntryID PartId ServiceEntryTypeID
1 1 3 1
2 2 4 2
3 2 4 1,2
dbo.Part
ID Desc Active (bitfield)
3 xyz 1
4 abc 1
Query as follows:
SELECT *
FROM ServiceEntry AS S
WHERE (S.RunLogEntryID is not null) AND (S.Reconciled=#ReconciledValue)
AND EXISTS (SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part on SEP.PartID = Part.ID
WHERE ((#ActivePart = 0 AND Part.Active is not null)
OR (#ActivePart = 1 and Part.Active = 0))
AND (#ServiceTypes is null
OR CHARINDEX(','+cast(SEP.ServiceTypeIDs as varchar(255))+',',','+#ServiceTypes+',') > 0))
OR (NOT EXISTS (SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part on SEP.PartID = Part.ID))
service entry has some records which contain runlogentry id of 0. If the runlogentryid value in service entry table is 0 then there will be no service entry part record for that service entry. Thats why I split them into two as you would notice from the query for example exists and not exists. the exists statement takes care of all service entries which have service entry parts and for these the filters will be applicable. If the filters have values then the not exist block will be not be needed because filters servicetypeids and activepart are for only records which have service entry parts.
So in other words if no params are passed the first exists block fetches service entries which have service parts and the not exists fetches service entries which have runlogentry id of 0 OR NOT null. This works great as it is. The problem is when the params are passed I would need to exclude the serviceentries which do not have service entry parts and when they are present I do not get the rigth results. I hope I did an okay job explaining the problem..Please help

Answer 1

Without trying to understand the rest of your SQL, if all you want to do is avoid the NOT EXISTS clause when your parameters are null you can do something like this.
SELECT *
FROM ServiceEntry AS S
JOIN
WHERE (S.RunLogEntryID is not null) AND (S.Reconciled=#ReconciledValue)
AND EXISTS (SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part on SEP.PartID = Part.ID
WHERE ((#ActivePart = 0 AND Part.Active is not null)
OR (#ActivePart = 1 and Part.Active = 0))
AND (#ServiceTypes is null
OR CHARINDEX(','+cast(SEP.ServiceTypeIDs as varchar(255))+',',','+#ServiceTypes+',') > 0))
OR (#ReconciledValue is null and #ActivePart is null and #ServiceTypes is null
and (NOT EXISTS (SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part on SEP.PartID = Part.ID)))

Answer 2

This probably isn't exactly what you want, to be honest the query seems all over the place.
You're probably looking for an active part filter like '(#ActivePart is null or #ActivePart = Part.Active)'. Your exists is implicitly taken care of by an inner join. A query that I believe is close to what you're looking for is below.
select *
FROM ServiceEntry AS S
INNER JOIN ServiceEntryPart AS SEP ON SEP.ServiceEntryID = S.ServiceEntryID
INNER JOIN Part AS P ON P.PartID = SEP.PartID
WHERE S.RunLogEntryID is not null
and S.Reconciled = #ReconciledValue
and (#ActivePart is null or #ActivePart = Part.Active)
and (#ServiceTypes is null or charindex(','+cast(SEP.ServiceTypeIDs as varchar(255))+',',','+#ServiceTypes+',') > 0

Answer 3

I can't be sure because I don't have the business definitions of your columns, but I suspect your conditions dealing with Part.Active are wrong. I would expect the values to be 0 or 1, not NULL or 0. So I should think the test should return TRUE when the parameter is NULL or the parameter matches the column.
Your CHARINDEX function has the parameters reversed.
You need additional parentheses to get the correct order of operation and your OR NOT EXISTS clause needs additional conditions to make it only true if the parameters are NULL.
I believe the following is much closer to what you are looking for. But I am worried about the ServiceTypes test. It will only work reliably if the parameter contains a single ServiceTypeID. If it contains multiple IDs it may not work. For example, I would think a parameter value of '1,3' should match a list of '1,2,3', but it won't.
SELECT *
FROM ServiceEntry AS S
WHERE (S.RunLogEntryID IS NOT NULL)
AND (S.Reconciled=#ReconciledValue)
AND( EXISTS(
SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part ON SEP.PartID = Part.ID
WHERE( #ActivePart IS NULL
OR #ActivePart = Part.Active
)
AND ( #ServiceTypes IS NULL
OR CHARINDEX( ','+#ServiceTypes+',',
','+cast(SEP.ServiceTypeIDs as varchar(255))+','
) > 0
)
)
OR( #ActivePart IS NULL
AND #ServiceTypes IS NULL
AND NOT EXISTS( SELECT ServiceEntryID
FROM ServiceEntryPart SEP
JOIN Part on SEP.PartID = Part.ID
)
)
)