Fix CURRENT ROW handling in window functions

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

@@ -352,7 +352,8 @@ public final class WindowFrame {
             int currentRow, boolean reverse) {
         int startIndex = getIndex(session, orderedRows, sortOrder, currentRow, starting, false);
         int endIndex = following != null ? getIndex(session, orderedRows, sortOrder, currentRow, following, true)
-                : currentRow;
+                : units == WindowFrameUnits.ROWS ? currentRow
+                        : toGroupEnd(orderedRows, sortOrder, currentRow, orderedRows.size() - 1);
         if (endIndex < startIndex) {
             return Collections.emptyIterator();
         }
@@ -442,7 +443,18 @@ public final class WindowFrame {
             }
             break;
         case CURRENT_ROW:
-            index = currentRow;
+            switch (units) {
+            case ROWS:
+                index = currentRow;
+                break;
+            case GROUPS:
+            case RANGE:
+                index = forFollowing ? toGroupEnd(orderedRows, sortOrder, currentRow, last)
+                        : toGroupStart(orderedRows, sortOrder, currentRow, 0);
+                break;
+            default:
+                throw DbException.getUnsupportedException("units=" + units);
+            }
             break;
         case FOLLOWING:
             switch (units) {

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

@@ -449,6 +449,26 @@ SELECT ID, VALUE, ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN 2 PRECEDING A
 > 8  9     (4, 5, 6)
 > rows: 8
 
+SELECT ID, VALUE,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) CP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) CF,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) RP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) RF,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE GROUPS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) GP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE GROUPS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) GF
+    FROM TEST;
+> ID VALUE CP                       CF                       RP                       RF                       GP                       GF
+> -- ----- ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ------------------------
+> 1  1     (1)                      (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8)
+> 2  1     (1, 2)                   (2, 3, 4, 5, 6, 7, 8)    (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8)
+> 3  5     (1, 2, 3)                (3, 4, 5, 6, 7, 8)       (1, 2, 3)                (3, 4, 5, 6, 7, 8)       (1, 2, 3)                (3, 4, 5, 6, 7, 8)
+> 4  8     (1, 2, 3, 4)             (4, 5, 6, 7, 8)          (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)          (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)
+> 5  8     (1, 2, 3, 4, 5)          (5, 6, 7, 8)             (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)          (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)
+> 6  8     (1, 2, 3, 4, 5, 6)       (6, 7, 8)                (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)          (1, 2, 3, 4, 5, 6)       (4, 5, 6, 7, 8)
+> 7  9     (1, 2, 3, 4, 5, 6, 7)    (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)
+> 8  9     (1, 2, 3, 4, 5, 6, 7, 8) (8)                      (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)
+> rows: 8
+
 SELECT *, ARRAY_AGG(ID) OVER (ORDER BY ID RANGE BETWEEN CURRENT ROW AND 1 PRECEDING) FROM TEST;
 > exception SYNTAX_ERROR_1
 
@@ -523,5 +543,25 @@ SELECT ID, VALUE, ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN 1 FOLLOWING A
 > 8  4     null
 > rows: 8
 
+SELECT ID, VALUE,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) CP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) CF,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) RP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) RF,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE GROUPS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) GP,
+    ARRAY_AGG(ID) OVER (ORDER BY VALUE GROUPS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) GF
+    FROM TEST;
+> ID VALUE CP                       CF                       RP                       RF                       GP                       GF
+> -- ----- ------------------------ ------------------------ ------------------------ ------------------------ ------------------------ ------------------------
+> 1  1     (1)                      (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8)
+> 2  1     (1, 2)                   (2, 3, 4, 5, 6, 7, 8)    (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8) (1, 2)                   (1, 2, 3, 4, 5, 6, 7, 8)
+> 3  2     (1, 2, 3)                (3, 4, 5, 6, 7, 8)       (1, 2, 3, 4)             (3, 4, 5, 6, 7, 8)       (1, 2, 3, 4)             (3, 4, 5, 6, 7, 8)
+> 4  2     (1, 2, 3, 4)             (4, 5, 6, 7, 8)          (1, 2, 3, 4)             (3, 4, 5, 6, 7, 8)       (1, 2, 3, 4)             (3, 4, 5, 6, 7, 8)
+> 5  3     (1, 2, 3, 4, 5)          (5, 6, 7, 8)             (1, 2, 3, 4, 5, 6)       (5, 6, 7, 8)             (1, 2, 3, 4, 5, 6)       (5, 6, 7, 8)
+> 6  3     (1, 2, 3, 4, 5, 6)       (6, 7, 8)                (1, 2, 3, 4, 5, 6)       (5, 6, 7, 8)             (1, 2, 3, 4, 5, 6)       (5, 6, 7, 8)
+> 7  4     (1, 2, 3, 4, 5, 6, 7)    (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)
+> 8  4     (1, 2, 3, 4, 5, 6, 7, 8) (8)                      (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)                   (1, 2, 3, 4, 5, 6, 7, 8) (7, 8)
+> rows: 8
+
 DROP TABLE TEST;
 > ok

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

@@ -136,25 +136,26 @@ SELECT *,
 > rows (ordered): 13
 
 SELECT ID, CATEGORY,
-    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) C,
-    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW EXCLUDE CURRENT ROW)
+    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) C,
+    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW EXCLUDE CURRENT ROW)
     FROM TEST FETCH FIRST 3 ROWS ONLY;
-> ID CATEGORY C    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY RANGE UNBOUNDED PRECEDING EXCLUDE CURRENT ROW)
-> -- -------- ---- ---------------------------------------------------------------------------------------------
+> ID CATEGORY C    NTH_VALUE(CATEGORY, 2) OVER (ORDER BY CATEGORY ROWS UNBOUNDED PRECEDING EXCLUDE CURRENT ROW)
+> -- -------- ---- --------------------------------------------------------------------------------------------
 > 1  1        null null
 > 2  1        1    null
 > 3  1        1    1
 > rows: 3
 
 SELECT ID, CATEGORY,
-    NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) C,
+    NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) C2,
+    NTH_VALUE(CATEGORY, 3) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING) C3,
     NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING EXCLUDE CURRENT ROW)
     FROM TEST OFFSET 10 ROWS;
-> ID CATEGORY C    NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT_ROW AND UNBOUNDED FOLLOWING EXCLUDE CURRENT ROW)
-> -- -------- ---- -------------------------------------------------------------------------------------------------------------------------------
-> 11 3        4    4
-> 12 4        4    null
-> 13 4        null null
+> ID CATEGORY C2 C3   NTH_VALUE(CATEGORY, 2) FROM LAST OVER (ORDER BY CATEGORY RANGE BETWEEN CURRENT_ROW AND UNBOUNDED FOLLOWING EXCLUDE CURRENT ROW)
+> -- -------- -- ---- -------------------------------------------------------------------------------------------------------------------------------
+> 11 3        4  3    4
+> 12 4        4  null null
+> 13 4        4  null null
 > rows: 3
 
 SELECT ID, CATEGORY,