How Do I Do A Query That Uses All Users?

Hello,

I am doing a website that incorporates SQL and one of the things is which user to query for. In this part, I would like to put
the variable 'AllUsers' which consists of all the users, do you have any suggestions on how this can be done, here is what I
have without a query for 'AllUsers' in HTML:

<SELECT NAME="targetUserID">
<OPTION VALUE="AllUsers">All Users</OPTION>
<!-- =queryString "select distinct rtrim(userID) from
Track..cUsers order by userID" -->
<!-- ?{sqlBlock $queryString crux 2000 0 -1 errorString tmpuserID -->
<OPTION VALUE= "<!-- $ $tmpuserID -->"
<!-- ({ $tmpuserID == $targetUserID --> SELECTED<!-- (} -->>
<!-- $ $tmpuserID --></OPTION>
<!-- ?}sqlBlock -->
</SELECT>

Here is what I thought would work, but it didn't:

<SELECT NAME="targetUserID">
<!-- =queryString "declare @AllUsers varchar(16) select @AllUsers = userID from Track..cUsers" -->
<!-- ?{sqlBlock $queryString crux 2000 0 -1 errorString AllUsers -->
<OPTION VALUE="AllUsers">All Users</OPTION>
<!-- ?}sqlBlock -->

<!-- =queryString "select distinct rtrim(userID) from
Track..cUsers order by userID" -->
<!-- ?{sqlBlock $queryString crux 2000 0 -1 errorString tmpuserID -->
<OPTION VALUE= "<!-- $ $tmpuserID -->"
<!-- ({ $tmpuserID == $targetUserID --> SELECTED<!-- (} -->>
<!-- $ $tmpuserID --></OPTION>
<!-- ?}sqlBlock -->
</SELECT>



In case you dont like how that looks here is what I thought would work just in SQL:

declare @AllUsers varchar(16)
select @AllUsers = userID
from Track..cUsers

I also tried to do it with my query for the final information, but that didnt work either it went something like this:

select DATEDIFF( hour, startTime, stopTime), cSlice.projectID " +
from Track..cSlice, Track..cProjects
where '" + $targetUserID + "' = 'AllUsers'
and clientID = '" + $targetClientID + "'
and state = 'Stopped'
and typeID = 'Billable'
and cSlice.projectID = cProjects.projectID
and startTime like '" + $targetMonth + "%'
or userID = '" + $targetUserID + "'
and clientID = '" + $targetClientID + "'
and state = 'Stopped'
and typeID = 'Billable'
and cSlice.projectID = cProjects.projectID
and startTime like '" + $targetMonth + "%'
order by cSlice.projectID

Any help would be greatly appreciated, Thank you for your time.
Nathan Czuba