Do not use ValueArray as key for PARTITION BY with 1 column

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

@@ -298,7 +298,7 @@ public abstract class SelectGroups {
      *            a key of partition
      * @return expression data or null
      */
-    public final PartitionData getWindowExprData(DataAnalysisOperation expr, ValueArray partitionKey) {
+    public final PartitionData getWindowExprData(DataAnalysisOperation expr, Value partitionKey) {
         if (partitionKey == null) {
             return windowData.get(expr);
         } else {
@@ -317,7 +317,7 @@ public abstract class SelectGroups {
      * @param object
      *            window expression data to set
      */
-    public final void setWindowExprData(DataAnalysisOperation expr, ValueArray partitionKey, PartitionData obj) {
+    public final void setWindowExprData(DataAnalysisOperation expr, Value partitionKey, PartitionData obj) {
         if (partitionKey == null) {
             Object old = windowData.put(expr, obj);
             assert old == null;

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

@@ -21,7 +21,6 @@ import org.h2.result.SortOrder;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
 import org.h2.value.Value;
-import org.h2.value.ValueArray;
 import org.h2.value.ValueInt;
 
 /**
@@ -184,7 +183,7 @@ public abstract class DataAnalysisOperation extends Expression {
 
     protected Object getWindowData(Session session, SelectGroups groupData, boolean forOrderBy) {
         Object data;
-        ValueArray key = over.getCurrentKey(session);
+        Value key = over.getCurrentKey(session);
         PartitionData partition = groupData.getWindowExprData(this, key);
         if (partition == null) {
             data = forOrderBy ? new ArrayList<>() : createAggregateData();
@@ -258,7 +257,7 @@ public abstract class DataAnalysisOperation extends Expression {
         PartitionData partition;
         Object data;
         boolean forOrderBy = over.getOrderBy() != null;
-        ValueArray key = over.getCurrentKey(session);
+        Value key = over.getCurrentKey(session);
         partition = groupData.getWindowExprData(this, key);
         if (partition == null) {
             // Window aggregates with FILTER clause may have no collected values

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

@@ -185,18 +185,22 @@ public final class Window {
      *            session
      * @return key for the current group, or null
      */
-    public ValueArray getCurrentKey(Session session) {
+    public Value getCurrentKey(Session session) {
         if (partitionBy == null) {
             return null;
         }
         int len = partitionBy.size();
-        Value[] keyValues = new Value[len];
-        // update group
-        for (int i = 0; i < len; i++) {
-            Expression expr = partitionBy.get(i);
-            keyValues[i] = expr.getValue(session);
+        if (len == 1) {
+            return partitionBy.get(0).getValue(session);
+        } else {
+            Value[] keyValues = new Value[len];
+            // update group
+            for (int i = 0; i < len; i++) {
+                Expression expr = partitionBy.get(i);
+                keyValues[i] = expr.getValue(session);
+            }
+            return ValueArray.get(keyValues);
         }
-        return ValueArray.get(keyValues);
     }
 
     /**

h2/src/test/org/h2/test/scripts/functions/window/row_number.sql

@@ -133,7 +133,7 @@ INSERT INTO TEST VALUES
     (4, 'b', 8);
 > update count: 4
 
-SELECT ROW_NUMBER() OVER(ORDER /**/ BY TYPE) RN, TYPE, SUM(CNT) SUM FROM TEST GROUP BY TYPE;
+SELECT ROW_NUMBER() OVER (ORDER /**/ BY TYPE) RN, TYPE, SUM(CNT) SUM FROM TEST GROUP BY TYPE;
 > RN TYPE SUM
 > -- ---- ---
 > 1  a    1
@@ -141,6 +141,16 @@ SELECT ROW_NUMBER() OVER(ORDER /**/ BY TYPE) RN, TYPE, SUM(CNT) SUM FROM TEST GR
 > 3  c    4
 > rows: 3
 
+SELECT A, B, C, ROW_NUMBER() OVER (PARTITION BY A, B) N FROM
+    VALUES (1, 1, 1), (1, 1, 2), (1, 2, 3), (2, 1, 4) T(A, B, C);
+> A B C N
+> - - - -
+> 1 1 1 1
+> 1 1 2 2
+> 1 2 3 1
+> 2 1 4 1
+> rows: 4
+
 SELECT RANK () OVER () FROM TEST;
 > exception SYNTAX_ERROR_2