GROUP BY queries with a self-join (join to the same table) that were grouped by…

GROUP BY queries with a self-join (join to the same table) that were grouped by columns with indexes returned the wrong result in some cases.

h2/src/main/org/h2/command/dml/Select.java

@@ -240,14 +240,14 @@ public class Select extends Query {
             if (index.getIndexType().getScan()) {
                 continue;
             }
-            if (isGroupSortedIndex(index)) {
+            if (isGroupSortedIndex(topTableFilter, index)) {
                 return index;
             }
         }
         return null;
     }
 
-    private boolean isGroupSortedIndex(Index index) {
+    private boolean isGroupSortedIndex(TableFilter tableFilter, Index index) {
         // check that all the GROUP BY expressions are part of the index
         Column[] indexColumns = index.getColumns();
         // also check that the first columns in the index are grouped
@@ -263,9 +263,11 @@ public class Select extends Query {
             }
             ExpressionColumn exprCol = (ExpressionColumn) expr;
             for (int j = 0; j < indexColumns.length; ++j) {
-                if (indexColumns[j].equals(exprCol.getColumn())) {
-                    grouped[j] = true;
-                    continue outerLoop;
+                if (tableFilter == exprCol.getTableFilter()) {
+                    if (indexColumns[j].equals(exprCol.getColumn())) {
+                        grouped[j] = true;
+                        continue outerLoop;
+                    }
                 }
             }
             // We didn't find a matching index column

h2/src/test/org/h2/test/test-1.1.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+create table test(id identity) as select x from system_range(1, 4);
+> ok
+
+select a.id from test a inner join test b on a.id > b.id and b.id < 3 group by a.id;
+> ID
+> --
+> 2
+> 3
+> 4
+> rows: 3
+
+drop table test;
+> ok
+
 create table test(id identity);
 > ok