removed too optimistic optimizations, which lead to wrong result

Author: datomo

core/src/main/java/org/polypheny/db/plan/AlgOptUtil.java

@@ -462,13 +462,14 @@ public static Exists createExistsPlan( AlgNode seekAlg, SubQueryType subQueryTyp
             return new Exists( seekAlg, false, true );
         }
 
-        switch ( logic ) {
+        /*switch ( logic ) { // this leads to too optimistic optimizations if not null and result empty
             case TRUE_FALSE_UNKNOWN:
             case UNKNOWN_AS_TRUE:
                 if ( notIn && !containsNullableFields( seekAlg ) ) {
                     logic = Logic.TRUE_FALSE;
                 }
-        }
+        }*/
+
         AlgNode ret = seekAlg;
         final AlgCluster cluster = seekAlg.getCluster();
         final RexBuilder rexBuilder = cluster.getRexBuilder();