On 17.11.2010 18:05, Tom Lane wrote:
> "Elliott Groszek"<elliott.groszek@navy.mil> writes:
>> The following SQL statements produce different query plans even though
>> "phone" is not reference in the SQL!
>
>> explain update customer set login_name =
>> (select "NESSOuserName" from person,phone
>> where person.cac_cert=customer.cac_cert);
>
>> explain update customer set login_name =
>> (select "NESSOuserName" from person
>> where person.cac_cert=customer.cac_cert);
>
> That's not a bug.
Particularly, note that they produce different results if "phone" table
is empty.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com