From: Jan Wieck <jwieck@debis.com>

Hi,

    as  proposed here comes the first patch for the query rewrite
    system.

  <for details, see archive dated Mon, 17 Aug 1998>

   now. Here some tested features, (examples included in the patch):

1.1) Subselects in the having clause 1.2) Double nested subselects
1.3) Subselects used in the where clause and in the having clause
     simultaneously 1.4) Union Selects using having 1.5) Indexes
on the base relations are used correctly 1.6) Unallowed Queries
are prevented (e.g. qualifications in the
     having clause that belong to the where clause) 1.7) Insert
into as select

2) Queries using the having clause on view relations also work
   but there are some restrictions:

2.1) Create View as Select ... Having ...; using base tables in
the select 2.1.1) The Query rewrite system:

2.1.2) Why are only simple queries allowed against a view from 2.1)
? 2.2) Select ... from testview1, testview2, ... having...; 3) Bug
in ExecMergeJoin ??


Regards Stefan

yyerror ones from bison. It also includes a few 'enhancements' to
the C programming style (which are, of course, personal).

The other patch removes the compilation of backend/lib/qsort.c, as
qsort() is a standard function in stdlib.h and can be used any
where else (and it is). It was only used in
backend/optimizer/geqo/geqo_pool.c, backend/optimizer/path/predmig.c,
and backend/storage/page/bufpage.c

> > Some or all of these changes might not be appropriate for v6.3,
since we > > are in beta testing and since they do not affect the
current functionality.  > > For those cases, how about submitting
patches based on the final v6.3 > > release?

There's more to come. Please review these patches. I ran the
regression tests and they only failed where this was expected
(random, geo, etc).

Cheers,

Jeroen

sequential scans! (I think it will also work with hash, index, etc
but I did not check it out! I made some High level changes which
should work for all access methods, but maybe I'm wrong. Please
let me know.)

Now it is possible to make queries like:

select s.sname, max(p.pid), min(p.pid) from part p, supplier s
where s.sid=p.sid group by s.sname having max(pid)=6 and min(pid)=1
or avg(pid)=4;

Having does not work yet for queries that contain a subselect
statement in the Having clause, I'll try to fix this in the next
days.

If there are some bugs, please let me know, I'll start to read the
mailinglists now!

Now here is the patch against the original 6.3 version (no snapshot!!):

Stefan

Add lock to i386 asm.

Pass List* of Aggregs into executor, and create needed array there.
No longer need to double-processs Aggregs with second copy in Query.

Fix crash when doing:

	select sum(x+1) from test where 1 > 0;

Add a few lines of test code playing with the unique flag for unions.
 Does not do much helpful yet.

Check for duplicate implicit index names and generate unique names.

Implement PRIMARY KEY and UNIQUE clauses using indices.