On Mon, 19 Feb 2001, Christopher Sawtell wrote:
> How can this happen?
>
> chris=# select name from boys_names where
> boys_names.number=(random()*225+1)::int4;
> name
> --------
> Fred
> Gunnar
> Manuel
> Rainer
> (4 rows)
It's not clear what you expected to see -- I'll guess you expected only
one row returned.
But random() is being called once for every row in the table -- it's not
surprising (if you have a lot of rows) that it comes up with a match more
than once. Sometimes it might even return no rows at all.
SQL is not the best language for picking random members of a set. You're
better off picking a random number in a procedural language and passing
that number as a constant to an embedded SQL query.
--
Tod McQuillin