possible mis-handling of nulls in views in 7.0.2

Hello,

   I'm running Postgres 7.0.2 and have run into a curious situation. I
got a back a null value in a select on VIEW that is defined as not
allowing that column to be null. Here's a screenshot:

marvel=> \d shipments;
View    = shipments
Query   = SELECT "web_data"."shipment_id", "web_data"."order_id",
"web_data"."customer_id", "web_data"."purchase_order_num", "web_data"."actual_ship
_date", "web_data"."pro_num", "sum"("web_data"."qt_ordered") AS
"qt_ordered", "sum"("web_data"."qt_shipped") AS "qt_shipped" FROM
"web_data" WHERE (
"web_data"."shipment_id" NOTNULL) GROUP BY "web_data"."shipment_id",
"web_data"."order_id", "web_data"."customer_id", "web_data"."actual_ship_date",
 "web_data"."pro_num", "web_data"."purchase_order_num";
+----------------------------------+----------------------------------+-------+
|              Field               |              Type                | Length|
+----------------------------------+----------------------------------+-------+
| shipment_id                      | varchar()                        |
  32 |
| order_id                         | varchar()                        |
 100 |
| customer_id                      | varchar()                        |
  10 |
| purchase_order_num               | varchar()                        |
 100 |
| actual_ship_date                 | date                             |
   4 |
| pro_num                          | varchar()                        |
 100 |
| qt_ordered                       | float8                           |
   8 |
| qt_shipped                       | float8                           |
   8 |
+----------------------------------+----------------------------------+-------+
marvel=>

### Notice that the shipment_id is NOTNULL
### now watch:

marvel=> select * from shipments where shipment_id is null;
shipment_id|order_id|customer_id|purchase_order_num|actual_ship_date|pro_num|qt_ordered|qt_shipped
-----------+--------+-----------+------------------+----------------+-------+----------+----------
           |        |           |                  |                |
   |          |
(1 row)
#############
It returns a row with a null shipment id!

I'm not sure what's happening here-- I tried to simplify this to a
simple case, but I couldn't reproduce the bug. Oddly, this null row
doesn't seem to appear in the table web_data that the view references. I
think it's easy enough to work around, but I'm curious what might be
happening here.

Thanks,

  -mark

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