Newbie: Rewriting A Query- How?

[Ken Brown]

Anyone any idea how I could rewrite this as a join - all the indexes are in
place and each of the components of this work fine - its only when the
combined subqueries are passed to the root query does it appear to go wrong
(Takes around 1.5 mins to complete and causes 100% processor utilisation
while executing).  (May be something for the developers to look at).
 
But in the meantime I need to get this going 
 
SELECT PROJID,PROJECTNAME
FROM  S_PROJECTREGISTER
WHERE  SNAPSHOTID = 56
AND   PROJID IN ( SELECT PROJID
          FROM  SL_PROGPROJ
          WHERE  SNAPSHOTID = 56
          AND   PROGID IN ( SELECT PROGID
                    FROM  SL_PORTPROG
                    WHERE  SNAPSHOTID = 56
                     AND PORTID IN(100994,100996) ) )
AND PROJECTSTATUS <> 'Potential'
 
Ken

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