Re: Question on how cardinality is calculated.

Ronnie,

It is always better to include the version details whenever you are
looking for some CBO specifics.  Do you see the num_rows as 111K for
table_1 in the dba_tables?

-Gopal


On Jan 10, 2008 9:06 AM, Ronnie Doggart <ronnie_doggart@xxxxxxxxx> wrote:
> All
>
> Does anyone know how Oracle calculates the cardinality of a query such
> as:
>
> Select * from table_1 where upper(case) like '%12345%';
>
> Execution Plan
> ----------------------------------------------------------
>   0      SELECT STATEMENT Optimizer=CHOOSE (Cost=131 Card=5553
> Bytes=621936)
>   1    0   TABLE ACCESS (FULL) OF 'TABLE_1' (Cost=131 Card=5553
> Bytes=621936)
>
> Oracle calculates that it is expecting 5553 rows from this query but I
> know it will only return 2.
>
> How does it do its estimate ?
>
>
>
> Ronnie Doggart
>
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