TandemPlugin: Further improvement of the matching SQL query

git-svn-id: https://server2.data-quest.de/svn/studip-plugins/TandemPlugin@2471 6a1f69d7-6018-4d13-bf90-b098e98c258d

classes/TandemMatching.class.php

@@ -76,21 +76,30 @@ class TandemMatching
             //     
             // SELECT request_profile_id FROM tandem_pairs WHERE status > '-1' 
             // AND request_profile_id = :profile_id:
-            //     The pair must be requested (0) or established (1) and
-            //     the profile-ID of the profile we're searching matches for
+            //     The profile-ID of the profile we're searching matches for
             //     must match either the request_profile_id or the 
             //     offer_profile_id. The latter filters out all requests 
             //     and established pairs that have been made with that profile.
             // 
-            // SELECT offer_profile_id FROM tandem_pairs WHERE status > '-1'
+            // SELECT offer_profile_id FROM tandem_pairs WHERE status > '-1':
             //     The same as with request_profile_id but here we're selecting
             //     the offer_profile_ids and use them in a UNION.
+            // 
+            // SELECT request_profile_id FROM tandem_pairs WHERE status = '1'
+            // and
+            // SELECT offer_profile_id FROM tandem_pairs WHERE status = '1':
+            //     We select the request_profile_ids and offer_profile_ids
+            //     of all established pairs.
             // )
             
             $sql .= "AND tandem_profiles.id NOT IN (
-                SELECT request_profile_id FROM tandem_pairs WHERE status > '-1' AND (request_profile_id = :profile_id OR offer_profile_id = :profile_id)
+                SELECT request_profile_id FROM tandem_pairs WHERE request_profile_id = :profile_id OR offer_profile_id = :profile_id
+                UNION
+                SELECT offer_profile_id FROM tandem_pairs WHERE offer_profile_id = :profile_id OR request_profile_id = :profile_id
+                UNION
+                SELECT request_profile_id FROM tandem_pairs WHERE status = '1'
                 UNION
-                SELECT offer_profile_id FROM tandem_pairs WHERE status > '-1' AND (offer_profile_id = :profile_id OR request_profile_id = :profile_id)
+                SELECT offer_profile_id FROM tandem_pairs WHERE status = '1'
             ) ";
         }