Re: Everlasting SQL query - Mailing list pgsql-general

From Michael Glaesemann
Subject Re: Everlasting SQL query
Date
Msg-id 0DA5D0F4-E085-11D8-AA48-000A95C88220@myrealbox.com
Whole thread Raw
In response to Everlasting SQL query  ("Joost Kraaijeveld" <J.Kraaijeveld@Askesis.nl>)
List pgsql-general
On Jul 28, 2004, at 7:08 PM, Joost Kraaijeveld wrote:
> select customer.id, customer.name, orders.id
> from customers, orders
> order by customer.id, orders.id
> limit 25
>
> The query runs forever (the longest I let it run is 500 seconds).


You have no join condition, so it's doing a full cartesian join (17518
x 88393 = 1,548,468,574 rows before the limit). Try this:

select customer.id, customer.name, orders.id
from customers c, orders o
where c.id = o.customerid
order by customer.id, orders.id
limit 25

Michael Glaesemann
grzm myrealbox com


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