On Thu, Jan 15, 2009 at 9:13 AM, dariuszs <span dir="ltr">&lt;<a href="mailto:dariuszs@svnp.com">dariuszs@svnp.com</a>&gt;</span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi,<br>
table1 - 1,000,000 records<br>
table2 - 300,000 records (from table1)<br>
table3 - 400,000 records (from table1)<br>
<br>
They key (key27) on all tables is varchar(27)<br>
SQL<br>
<br>
select count(*) from table1 where key27 in (select key27 from &nbsp;table2,<br>
table3); (the answer should be 700,000)<br>
<br>
At this point server crashed.<br>
<br>
I&#39;m trying to join 3 tables to get a count on table1 only when there is<br>
a match in table2 or table3. Could you provide me with a sample how to<br>
properly match 3 or more tables based on the match key? Thank you. Dariusz.<br>
</blockquote></div><br>Just curious, does it work if you don&#39;t have a cartesian product in the subquery?&nbsp; (there is no condition to match table2 rows with table3 rows)<br>