Re: [HACKERS] Re: [GENERAL] Re: [PHP3] Re: PostgreSQL vs Mysql comparison

On Wed, 6 Oct 1999, Bruce Momjian wrote:

> > Thanks bruce and hermit for all the comments,
> > I looked into the book "The SQL Standard" fourth edition of Date 
> > and in the appendixes page 439 they have an example which they 
> > discuss. The example is: select count(*) as x from mt having 0 = 0; 
> > with an empty table they say logically correct it should return one 
> > column and no rows but sql gives a table of one column and one 
> > row. So I think it's true that HAVING has to have an aggregation 
> > but it will also be possible use a non-aggregation.
> > 
> > If I look in our crash-me output page (this is a handy thing for this 
> > kind of questions) and look for all the other db's to see what they 
> > do I can say the following thing:
> > Informix,Access,Adabas,db2,empress,ms-sql,oracle,solid and 
> > sybase are all supporting non-aggregation in having clause.
> > At this moment everyone except postgres is supporting it.
> > 
> > The change which I can made is to remove the if structure around 
> > the having tests so that having with group functions will also be 
> > tested in the crash-me test.
> > 
> > I will try the patch of bruce for the comment part. It shouldn't be the 
> > way that the perl module is stripping the comments of the querie 
> > but it is possible and if it is possible it will be a bug in the DBD 
> > postgresql perl module.
> 
> Maybe we should support the HAVING without aggregates.  What do others
> think?

If we are the only one that doesn't, it just makes it harder for those
moving from Oracle/Informix/etc if they happen to be using such queries...

How hard would it be to implement?

Marc G. Fournier                   ICQ#7615664               IRC Nick: Scrappy
Systems Administrator @ hub.org 
primary: scrappy@hub.org           secondary: scrappy@{freebsd|postgresql}.org