EJB QL queries with WHERE clauses that contain at least one OR or AND
and have a simple conditional expression with at least one navigation
expression that requires a join can produce invalid results under
certain conditions.  

e.g. SELECT OBJECT(o) FROM Order AS  o WHERE
((o.quantity  > 1) OR (o.shipping_address.city  LIKE '%p%'))

The generated SQL is : 

SQL : SELECT "o"."orderId"


"OrderEJB_shipping_address_AddressEJB_Table" "@tmp2"

WHERE (("o"."quantity"  > 1 ) OR ("@tmp1"."city"  LIKE '%p%' )) AND
(("o"."orderId" = "@tmp2"."_OrderEJB_orderId" AND
"@tmp2"."_AddressEJB_addressId" = "@tmp1"."addressId"))

In this case, the generated sql does not correctly preserve the OR
condition.  Since the join tables are in the top-level FROM clause,
if those tables are empty it will wipe out the result set, even if
the o.quantity > 1 is true for some rows.  

N/A

in cases where evaluating a simple conditional expression requires additional
join tables, generate a sub-query instead of putting sql at top-level.
This will isolate the evaluation and produce the correct results.
E.g. :
 
SELECT OBJECT(o) FROM Order AS  o WHERE
             ((o.quantity  > 1) OR (o.shipping_address.city  LIKE '%p%'))

BEFORE :
The generated SQL is : 

SELECT "o"."orderId"


"OrderEJB_shipping_address_AddressEJB_Table" "@tmp2"

WHERE (("o"."quantity"  > 1 ) OR ("@tmp1"."city"  LIKE '%p%' )) AND
      (("o"."orderId" = "@tmp2"."_OrderEJB_orderId" AND
       "@tmp2"."_AddressEJB_addressId" = "@tmp1"."addressId"))

AFTER :

SELECT "o"."orderId" 

FROM "OrderBeanTable" "o" 

WHERE (("o"."quantity"  > 1 ) OR  
      EXISTS (SELECT * FROM "AddressBeanTable" "@tmp1" ,
     "OrderEJB_shipping_address_AddressEJB_Table" "@tmp2" WHERE
     ("@tmp1"."city"  LIKE '%p%' ) AND (("o"."orderId" =
     "@tmp2"."_OrderEJB_orderId" AND "@tmp2"."_AddressEJB_addressId" =
     "@tmp1"."addressId"))) )

This bug appears to have been closed erroneously.  
Please see http://forum.java.sun.com/
thread.jsp?forum=13&thread=263005