Re: SQL subquery to supply table name?

On Thursday 26 September 2002 06:01 pm, Martijn van Oosterhout wrote:
> I think the basic response is "don't do that". SQL doesn't support queries
> where the tables are not predetermined. The query planner would have a
> terrible time since it would not be able to estimate costs prior to
> execution.

It's too bad for the query planner then! :-)  (I'm not a Postgresql guru and I
really don't know what the problem would be if the query planner could not
estimate costs beforehand. Don't take my "It's too bad" comment seriously!)

> Since all your "subtables" are likely to have the same structure, why not
> store them all in one table. Any particular reason?

They don't have the same structure. Similar enough for my purposes but not the
same.  In all but two cases where I handle the data from the sub-tables, I
handle columns common to the different tables (so these tables are not
normalized completely but I knew that going in) or I hadle all the data as a
unit.  The two places where I handle the data specifically I determine which
type of review it is and direct the user to a different web page to deal with
the specifics.

I can solve this problem by running two queries rather one query with a
subquery but that's not as elegant.  I was hoping to find a more elegant
solution based on a sub-query.

Scott