Fix NPE in window functions with unknown columns

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

@@ -113,6 +113,7 @@ public abstract class AbstractAggregate extends Expression {
     @Override
     public Expression optimize(Session session) {
         if (over != null) {
+            over.optimize(session);
             ArrayList<SelectOrderBy> orderBy = over.getOrderBy();
             if (orderBy != null) {
                 overOrderBySort = createOrder(session, orderBy, getNumExpressions());

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

@@ -81,6 +81,25 @@ public final class Window {
         }
     }
 
+    /**
+     * Try to optimize the window conditions.
+     *
+     * @param session
+     *            the session
+     */
+    public void optimize(Session session) {
+        if (partitionBy != null) {
+            for (int i = 0; i < partitionBy.size(); i++) {
+                partitionBy.set(i, partitionBy.get(i).optimize(session));
+            }
+        }
+        if (orderBy != null) {
+            for (SelectOrderBy o : orderBy) {
+                o.expression = o.expression.optimize(session);
+            }
+        }
+    }
+
     /**
      * Tell the expression columns whether the table filter can return values
      * now. This is used when optimizing the query.

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

@@ -3,6 +3,12 @@
 -- Initial Developer: H2 Group
 --
 
+SELECT FIRST_VALUE(1) OVER (PARTITION BY ID);
+> exception COLUMN_NOT_FOUND_1
+
+SELECT FIRST_VALUE(1) OVER (ORDER BY ID);
+> exception COLUMN_NOT_FOUND_1
+
 CREATE TABLE TEST (ID INT PRIMARY KEY, CATEGORY INT, VALUE INT);
 > ok