Optimize EXCLUDE GROUP part 1

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

@@ -535,21 +535,25 @@ public final class WindowFrame {
             } else {
                 return biIterator(orderedRows, startIndex, currentRow - 1, currentRow + 1, endIndex, reverse);
             }
-            return plainIterator(orderedRows, startIndex, endIndex, reverse);
         } else {
-            BitSet set = new BitSet(endIndex + 1);
-            set.set(startIndex, endIndex + 1);
             int exStart = toGroupStart(orderedRows, sortOrder, currentRow, startIndex);
             int exEnd = toGroupEnd(orderedRows, sortOrder, currentRow, endIndex);
-            set.clear(exStart, exEnd + 1);
-            if (exclusion == WindowFrameExclusion.EXCLUDE_TIES) {
-                set.set(currentRow);
-            }
-            if (set.isEmpty()) {
-                return Collections.emptyIterator();
+            if (exEnd < startIndex || exStart > endIndex) {
+                // Nothing to do
+            } else {
+                BitSet set = new BitSet(endIndex + 1);
+                set.set(startIndex, endIndex + 1);
+                set.clear(exStart, exEnd + 1);
+                if (exclusion == WindowFrameExclusion.EXCLUDE_TIES) {
+                    set.set(currentRow);
+                }
+                if (set.isEmpty()) {
+                    return Collections.emptyIterator();
+                }
+                return reverse ? new BitSetReverseItr(orderedRows, set) : new BitSetItr(orderedRows, set);
             }
-            return reverse ? new BitSetReverseItr(orderedRows, set) : new BitSetItr(orderedRows, set);
         }
+        return plainIterator(orderedRows, startIndex, endIndex, reverse);
     }
 
     /**

h2/src/test/org/h2/test/scripts/functions/aggregate/array-agg.sql

@@ -384,6 +384,40 @@ SELECT *,
 > 8  9     (4, 5, 6, 7, 8) (7, 8)
 > rows: 8
 
+SELECT ID, VALUE,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN 2 PRECEDING AND 2 FOLLOWING EXCLUDE GROUP) G,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN 2 PRECEDING AND 2 FOLLOWING EXCLUDE TIES) T
+    FROM TEST;
+> ID VALUE G            T
+> -- ----- ------------ ---------------
+> 1  1     (3)          (1, 3)
+> 2  1     (3, 4)       (2, 3, 4)
+> 3  5     (1, 2, 4, 5) (1, 2, 3, 4, 5)
+> 4  8     (2, 3)       (2, 3, 4)
+> 5  8     (3, 7)       (3, 5, 7)
+> 6  8     (7, 8)       (6, 7, 8)
+> 7  9     (5, 6)       (5, 6, 7)
+> 8  9     (6)          (6, 8)
+> rows: 8
+
+SELECT ID, VALUE, ARRAY_AGG(ID) OVER(ORDER BY VALUE ROWS BETWEEN 1 FOLLOWING AND 2 FOLLOWING EXCLUDE GROUP) G
+  FROM TEST ORDER BY ID FETCH FIRST 3 ROWS ONLY;
+> ID VALUE G
+> -- ----- ------
+> 1  1     (3)
+> 2  1     (3, 4)
+> 3  5     (4, 5)
+> rows (ordered): 3
+
+SELECT ID, VALUE, ARRAY_AGG(ID) OVER(ORDER BY VALUE ROWS BETWEEN 2 PRECEDING AND 1 PRECEDING EXCLUDE GROUP) G
+  FROM TEST ORDER BY ID FETCH FIRST 3 ROWS ONLY;
+> ID VALUE G
+> -- ----- ------
+> 1  1     null
+> 2  1     null
+> 3  5     (1, 2)
+> rows (ordered): 3
+
 SELECT *, ARRAY_AGG(ID) OVER (ORDER BY ID RANGE BETWEEN CURRENT ROW AND 1 PRECEDING) FROM TEST;
 > exception SYNTAX_ERROR_1
 

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

@@ -167,5 +167,55 @@ SELECT ID, CATEGORY,
 > 13 4        3
 > rows: 3
 
+SELECT ID, CATEGORY,
+    NTH_VALUE(CATEGORY, 1) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) F1,
+    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) F2,
+    NTH_VALUE(CATEGORY, 5) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) F5,
+    NTH_VALUE(CATEGORY, 5) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) L5,
+    NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) L2,
+    NTH_VALUE(CATEGORY, 1) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE GROUP) L1
+    FROM TEST ORDER BY ID;
+> ID CATEGORY F1 F2 F5 L5 L2 L1
+> -- -------- -- -- -- -- -- --
+> 1  1        2  2  3  3  4  4
+> 2  1        2  2  3  3  4  4
+> 3  1        2  2  3  3  4  4
+> 4  1        2  2  3  3  4  4
+> 5  1        2  2  3  3  4  4
+> 6  1        2  2  3  3  4  4
+> 7  2        1  1  1  3  4  4
+> 8  2        1  1  1  3  4  4
+> 9  3        1  1  1  1  4  4
+> 10 3        1  1  1  1  4  4
+> 11 3        1  1  1  1  4  4
+> 12 4        1  1  1  2  3  3
+> 13 4        1  1  1  2  3  3
+> rows (ordered): 13
+
+SELECT ID, CATEGORY,
+    NTH_VALUE(CATEGORY, 1) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) F1,
+    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) F2,
+    NTH_VALUE(CATEGORY, 5) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) F5,
+    NTH_VALUE(CATEGORY, 5) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) L5,
+    NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) L2,
+    NTH_VALUE(CATEGORY, 1) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING EXCLUDE TIES) L1
+    FROM TEST ORDER BY ID;
+> ID CATEGORY F1 F2 F5 L5 L2 L1
+> -- -------- -- -- -- -- -- --
+> 1  1        1  2  3  3  4  4
+> 2  1        1  2  3  3  4  4
+> 3  1        1  2  3  3  4  4
+> 4  1        1  2  3  3  4  4
+> 5  1        1  2  3  3  4  4
+> 6  1        1  2  3  3  4  4
+> 7  2        1  1  1  3  4  4
+> 8  2        1  1  1  3  4  4
+> 9  3        1  1  1  2  4  4
+> 10 3        1  1  1  2  4  4
+> 11 3        1  1  1  2  4  4
+> 12 4        1  1  1  2  3  4
+> 13 4        1  1  1  2  3  4
+> rows (ordered): 13
+
 DROP TABLE TEST;
 > ok