Require ORDER BY for window functions where required by standard

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

@@ -10,6 +10,7 @@ import java.util.HashMap;
 import java.util.Iterator;
 
 import org.h2.command.dml.Select;
+import org.h2.command.dml.SelectOrderBy;
 import org.h2.engine.Session;
 import org.h2.expression.Expression;
 import org.h2.message.DbException;
@@ -411,6 +412,19 @@ public class WindowFunction extends AbstractAggregate {
                 throw DbException.getSyntaxError(sql, sql.length() - 1);
             }
         }
+        ArrayList<SelectOrderBy> orderBy = over.getOrderBy();
+        if (orderBy == null || orderBy.isEmpty()) {
+            switch (type) {
+            case RANK:
+            case DENSE_RANK:
+            case NTILE:
+            case LEAD:
+            case LAG:
+                String sql = getSQL();
+                throw DbException.getSyntaxError(sql, sql.length() - 1, "ORDER BY");
+            default:
+            }
+        }
         super.optimize(session);
         if (args != null) {
             for (int i = 0; i < args.length; i++) {

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

@@ -129,6 +129,12 @@ SELECT LEAD(VALUE, -1) OVER (ORDER BY ID) FROM TEST;
 SELECT LAG(VALUE, -1) OVER (ORDER BY ID) FROM TEST;
 > exception INVALID_VALUE_2
 
+SELECT LEAD(VALUE) OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
+
+SELECT LAG(VALUE) OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
+
 SELECT LEAD(VALUE) OVER (ORDER BY ID RANGE CURRENT ROW) FROM TEST;
 > exception SYNTAX_ERROR_1
 

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

@@ -113,5 +113,8 @@ SELECT NTILE(X) OVER (ORDER BY X) FROM (SELECT * FROM SYSTEM_RANGE(1, 6));
 > 6
 > rows (ordered): 6
 
+SELECT NTILE(X) OVER () FROM (SELECT * FROM SYSTEM_RANGE(1, 1));
+> exception SYNTAX_ERROR_2
+
 SELECT NTILE(X) OVER (ORDER BY X RANGE CURRENT ROW) FROM (SELECT * FROM SYSTEM_RANGE(1, 1));
 > exception SYNTAX_ERROR_1

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

@@ -20,8 +20,6 @@ INSERT INTO TEST VALUES
 
 SELECT *,
     ROW_NUMBER() OVER () RN,
-    RANK() OVER () RK,
-    DENSE_RANK() OVER () DR,
     ROUND(PERCENT_RANK() OVER (), 2) PR,
     ROUND(CUME_DIST() OVER (), 2) CD,
 
@@ -32,17 +30,17 @@ SELECT *,
     ROUND(CUME_DIST() OVER (ORDER BY ID), 2) CDO
 
     FROM TEST;
-> ID CATEGORY VALUE RN RK DR PR  CD  RNO RKO DRO PRO  CDO
-> -- -------- ----- -- -- -- --- --- --- --- --- ---- ----
-> 1  1        11    1  1  1  0.0 1.0 1   1   1   0.0  0.11
-> 2  1        12    2  1  1  0.0 1.0 2   2   2   0.13 0.22
-> 3  1        13    3  1  1  0.0 1.0 3   3   3   0.25 0.33
-> 4  2        21    4  1  1  0.0 1.0 4   4   4   0.38 0.44
-> 5  2        22    5  1  1  0.0 1.0 5   5   5   0.5  0.56
-> 6  3        31    6  1  1  0.0 1.0 6   6   6   0.63 0.67
-> 7  3        32    7  1  1  0.0 1.0 7   7   7   0.75 0.78
-> 8  3        33    8  1  1  0.0 1.0 8   8   8   0.88 0.89
-> 9  4        41    9  1  1  0.0 1.0 9   9   9   1.0  1.0
+> ID CATEGORY VALUE RN PR  CD  RNO RKO DRO PRO  CDO
+> -- -------- ----- -- --- --- --- --- --- ---- ----
+> 1  1        11    1  0.0 1.0 1   1   1   0.0  0.11
+> 2  1        12    2  0.0 1.0 2   2   2   0.13 0.22
+> 3  1        13    3  0.0 1.0 3   3   3   0.25 0.33
+> 4  2        21    4  0.0 1.0 4   4   4   0.38 0.44
+> 5  2        22    5  0.0 1.0 5   5   5   0.5  0.56
+> 6  3        31    6  0.0 1.0 6   6   6   0.63 0.67
+> 7  3        32    7  0.0 1.0 7   7   7   0.75 0.78
+> 8  3        33    8  0.0 1.0 8   8   8   0.88 0.89
+> 9  4        41    9  0.0 1.0 9   9   9   1.0  1.0
 > rows (ordered): 9
 
 SELECT *,
@@ -86,19 +84,26 @@ SELECT *,
 > rows (ordered): 9
 
 SELECT
-    ROW_NUMBER() OVER () RN,
-    RANK() OVER () RK,
-    DENSE_RANK() OVER () DR,
+    ROW_NUMBER() OVER (ORDER BY CATEGORY) RN,
+    RANK() OVER (ORDER BY CATEGORY) RK,
+    DENSE_RANK() OVER (ORDER BY CATEGORY) DR,
     PERCENT_RANK() OVER () PR,
-    CUME_DIST() OVER () CD
-    FROM TEST GROUP BY CATEGORY;
-> RN RK DR PR  CD
-> -- -- -- --- ---
-> 1  1  1  0.0 1.0
-> 2  1  1  0.0 1.0
-> 3  1  1  0.0 1.0
-> 4  1  1  0.0 1.0
-> rows: 4
+    CUME_DIST() OVER () CD,
+    CATEGORY C
+    FROM TEST GROUP BY CATEGORY ORDER BY RN;
+> RN RK DR PR  CD  C
+> -- -- -- --- --- -
+> 1  1  1  0.0 1.0 1
+> 2  2  2  0.0 1.0 2
+> 3  3  3  0.0 1.0 3
+> 4  4  4  0.0 1.0 4
+> rows (ordered): 4
+
+SELECT RANK() OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
+
+SELECT DENSE_RANK() OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
 
 SELECT ROW_NUMBER() OVER (ORDER BY ID RANGE CURRENT ROW) FROM TEST;
 > exception SYNTAX_ERROR_1
@@ -136,5 +141,11 @@ SELECT ROW_NUMBER() OVER(ORDER /**/ BY TYPE) RN, TYPE, SUM(CNT) SUM FROM TEST GR
 > 3  c    4
 > rows: 3
 
+SELECT RANK () OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
+
+SELECT DENSE_RANK () OVER () FROM TEST;
+> exception SYNTAX_ERROR_2
+
 DROP TABLE TEST;
 > ok