Fix and test some distinct window aggregates

h2/src/main/org/h2/expression/aggregate/AggregateDataDefault.java

@@ -129,8 +129,7 @@ class AggregateDataDefault extends AggregateData {
     @Override
     Value getValue(Database database, int dataType, boolean distinct) {
         if (distinct) {
-            count = 0;
-            groupDistinct(database, dataType);
+            return getDistinct(database, dataType);
         }
         Value v = null;
         switch (aggregateType) {
@@ -192,14 +191,15 @@ class AggregateDataDefault extends AggregateData {
         return a;
     }
 
-    private void groupDistinct(Database database, int dataType) {
+    private Value getDistinct(Database database, int dataType) {
         if (distinctValues == null) {
-            return;
+            return ValueNull.INSTANCE;
         }
-        count = 0;
+        AggregateDataDefault d = new AggregateDataDefault(aggregateType);
         for (Value v : distinctValues.keys()) {
-            add(database, dataType, false, v);
+            d.add(database, dataType, false, v);
         }
+        return d.getValue(database, dataType, false);
     }
 
 }

h2/src/test/org/h2/test/scripts/functions/aggregate/count.sql

@@ -69,3 +69,17 @@ SELECT NR FROM (SELECT COUNT(ID) OVER (ORDER BY NAME) AS NR,
 
 DROP TABLE TEST;
 > ok
+
+SELECT I, V, COUNT(V) OVER W C, COUNT(DISTINCT V) OVER W D FROM
+    VALUES (1, 1), (2, 1), (3, 1), (4, 1), (5, 2), (6, 2), (7, 3) T(I, V)
+    WINDOW W AS (ORDER BY I);
+> I V C D
+> - - - -
+> 1 1 1 1
+> 2 1 2 1
+> 3 1 3 1
+> 4 1 4 1
+> 5 2 5 2
+> 6 2 6 2
+> 7 3 7 3
+> rows (ordered): 7

h2/src/test/org/h2/test/scripts/functions/aggregate/sum.sql

@@ -81,3 +81,17 @@ SELECT
 > 7  28 28    15    36
 > 8  36 36    8     36
 > rows (ordered): 8
+
+SELECT I, V, SUM(V) OVER W S, SUM(DISTINCT V) OVER W D FROM
+    VALUES (1, 1), (2, 1), (3, 1), (4, 1), (5, 2), (6, 2), (7, 3) T(I, V)
+    WINDOW W AS (ORDER BY I);
+> I V S  D
+> - - -- -
+> 1 1 1  1
+> 2 1 2  1
+> 3 1 3  1
+> 4 1 4  1
+> 5 2 6  3
+> 6 2 8  3
+> 7 3 11 6
+> rows (ordered): 7