Taking a step backward, what is the table supposed to describe / store data about? Are the values {present, absent, disallowed} mutually exclusive?

Why not just put the "absent" or whatever in another column? If you try to stuff everything in the same column, querying your data is going to be a nightmare.

Does your parameter have a default set? If not, and you don't enter anything, the report won't run because the stored procedure can't return any data.

You've been here over 500 times and can't even post an answerable question with proper sample data??? Please read this article and repost.

Create a variable to store the value and then pass it?

Sounds like you could use a Windowing function to do this... this isn't right, but should give you some idea.

SELECT SuperTaskID
, SubTaskID
, ID
, TaskName
,...

I tried running your CREATE TABLE and INSERT scripts, but they wouldn't compile.  Oh wait, there were no scripts.  Hence no useful reply,,,

Maybe I should make this bigger...

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You would just OUTER join your query to the table of internal users.  The result would be that any external users would generate a NULL in the Users table, so...

If you're not allowed to create the function, ask someone with permissions to do it.  If they want their answers, they're going to have to comply. =)  The function can...

First step is to give whoever did this a beating. Databases like this are pretty much useless.

Here's most of a solution:
link to DelimitedSplit8K

DECLARE @MyString...

UPDATE TimeAccountMovement
SET ownerID = DutyRosterShift
WHERE A.orig_owner_ID = 999999
AND B.Orig_id = A.OwnerID;