subquery - how to refer to outer query value - sql

Question

The query below is working fine:
SELECT
tblCase.ID AS CaseID, tblCase.UserID AS MyCasesFilter,
tblGroupMembership.UserID AS GroupShareFilter,
tblDirectCaseSharing.ReceiverUserID AS DirectShareFilter, tblCase.EntryDate,
tblUser.LastName AS CaseAuthor, tblCase.Name AS CaseName,
COUNT(DISTINCT tblCaseImage.ID) AS TotalImages,
tblCaseType.Name AS CaseType, tblCase.SiteName, tblCase.Category,
tblCase.FollowUpDateTime, tblCase.Notes
FROM
tblDirectCaseSharing
RIGHT OUTER JOIN
tblCase
INNER JOIN tblUser ON tblCase.UserID = tblUser.ID ON tblDirectCaseSharing.CaseID = tblCase.ID
LEFT OUTER JOIN
tblGroupMembership
INNER JOIN
tblGroupCase ON tblGroupMembership.GroupID = tblGroupCase.GroupID ON tblCase.ID = tblGroupCase.CaseID
LEFT OUTER JOIN
tblCaseType ON tblCase.CaseTypeID = tblCaseType.ID
LEFT OUTER JOIN
tblCaseImage ON tblCase.ID = tblCaseImage.CaseID
GROUP BY
tblCase.ID, tblCaseType.Name, tblCase.SiteName, tblCase.EntryDate,
tblCase.Category, tblCase.FollowUpDateTime, tblCase.Notes, tblCase.UserID,
tblGroupMembership.UserID, tblDirectCaseSharing.ReceiverUserID,
tblUser.LastName, tblCase.Name
HAVING
(tblCase.UserID = 1)
AND (tblGroupMembership.UserID = 2)
AND (tblDirectCaseSharing.ReceiverUserID = 3)
ORDER BY
tblCase.EntryDate DESC
I want to add an additional select column to the above result using a select subquery which is:
STUFF((
SELECT ', ' +tblGroup.Name as [text()]
FROM tblCase INNER JOIN
tblGroupCase ON tblCase.ID = tblGroupCase.CaseID INNER JOIN
tblGroup ON tblGroupCase.GroupID = tblGroup.ID
WHERE tblCase.ID = ***
FOR XML PATH('')
),1,2,'')
AS ConcatGroupShares
The select subquery has a where clause and I need to get the tblcase.id which is the first column of the result set. how to i reference that value in the subquery.

Answer 1

Put an alias name in the main query
SELECT
tcase.ID AS CaseID, tblCase.UserID AS MyCasesFilter,
tblGroupMembership.UserID AS GroupShareFilter,
tblDirectCaseSharing.ReceiverUserID AS DirectShareFilter, tblCase.EntryDate,
tblUser.LastName AS CaseAuthor, tblCase.Name AS CaseName,
COUNT(DISTINCT tblCaseImage.ID) AS TotalImages,
tblCaseType.Name AS CaseType, tblCase.SiteName, tblCase.Category,
tblCase.FollowUpDateTime, tblCase.Notes
FROM
tblDirectCaseSharing
RIGHT OUTER JOIN
tblCase As tcase <=====
And use this alias name in the subquery:
STUFF((
SELECT ', ' +tblGroup.Name as [text()]
FROM tblCase INNER JOIN
tblGroupCase ON tblCase.ID = tblGroupCase.CaseID INNER JOIN
tblGroup ON tblGroupCase.GroupID = tblGroup.ID
WHERE tblCase.ID = tcase.id
FOR XML PATH('')
),1,2,'')
AS ConcatGroupShares
More about co-related sub-queries:
http://en.wikipedia.org/wiki/Correlated_subquery