URGENT! How many rows will be returned?

Hi,

How can I know how many rows will be returned from the query

SELECT *
FROM table1 t1, table2 t2
where t1.column1 = t2.cloumn2;

I know it can be done by

SELECT count(*)
FROM table1 t1, table2 t2
where t1.column1 = t2.cloumn2;

But I don't want to touch the actual data to get the information. Is there any statistics about that, and where is it stored? How can I get it by program?

I am wondering how the optimizer works it out.

Thanks in advance.

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Before you buy. Received on Thu Oct 21 1999 - 00:00:00 CEST