Question

i have the following query

SELECT DISTINCT dr.Revision 
FROM tblActionHeader ah 
    INNER JOIN tblActionType at ON at.ActionTypeID = ah.ActionTypeID 
    INNER JOIN tblDocumentRevisionActionHeader drah ON drah.ActionHeaderID = ah.ActionHeaderID 
    INNER JOIN tblDocumentRevision dr on dr.DocumentRevisionID = drah.DocumentRevisionID 
    INNER JOIN tblDocumentHeader dh on dh.DocumentHeaderID = dr.DocumentHeaderID 
WHERE at.ActionTypeID=2 
UNION SELECT '(All)' 
      FROM tblActionHeader ah

it returns the following result set

-
(All)
0
0a
1

i need ‘(All)’ to take at the top of the result set how can i do this?

Answer 1

Two ways – first would be to put the “All” at the top of the UNION:

SELECT '(All)' AS revision
UNION ALL
SELECT DISTINCT dr.Revision 
  FROM tblActionHeader ah 
  JOIN tblActionType at ON at.ActionTypeID = ah.ActionTypeID 
  JOIN tblDocumentRevisionActionHeader drah ON drah.ActionHeaderID = ah.ActionHeaderID   
  JOIN tblDocumentRevision dr ON dr.DocumentRevisionID = drah.DocumentRevisionID 
  JOIN tblDocumentHeader dh ON dh.DocumentHeaderID = dr.DocumentHeaderID 
 WHERE at.ActionTypeID = 2 

The second is to assign an arbitrary value for ordering by:

SELECT x.revision
  FROM (SELECT '(All)' AS revision, 1 AS sort_order 
         UNION ALL
        SELECT DISTINCT dr.Revision, 2 AS sort_order 
          FROM tblActionHeader ah 
          JOIN tblActionType at ON at.ActionTypeID = ah.ActionTypeID 
          JOIN tblDocumentRevisionActionHeader drah ON drah.ActionHeaderID = ah.ActionHeaderID   
          JOIN tblDocumentRevision dr ON dr.DocumentRevisionID = drah.DocumentRevisionID 
          JOIN tblDocumentHeader dh ON dh.DocumentHeaderID = dr.DocumentHeaderID 
         WHERE at.ActionTypeID = 2) x
ORDER BY x.sort_order, x.revision

I used the derived table approach in this example to make sure that only the revision column is in the final result set.

Use UNION ALL if you know the values will be distinct/unique — UNION removes duplicates, and is slower for that reason.