Re: Undocumented SQL-Feature?

On Thu, 25 Jun 1998, Martin Berns wrote: > try the following statement against stores7: > > select count(*) * 100/(select count(*) from cust_calls) percent > from cust_calls where call_code = 'I';> > Surprise (at least to me): it works! > Syntax say select-list may consist of ecpressions only and > a select-statement isn't an expression. No, you've found a feature which has been around for a while (several years) but is not documented in any manual I've seen. It isn't always clear exactly what you can do with those sub-selects; I don't think they can be used in the FROM clause (where they'd be most useful!), and it is not always clear how the variable are scoped -- trying to do correlated sub-queries can be tricky! Yours, Jonathan Leffler (jleffler@informix.com) #include <witticism.h> Guardian of DBD::Informix -- see http://www.perl.com/CPAN