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From: Gary Stainburn <gary.stainburn@ringways.co.uk>
Organization: Ringways Garages Ltd
To: Philip Warner <pjw@rhyme.com.au>, pgsql-sql@postgresql.org
Subject: Re: Help on (sub)-select
Date: Fri, 20 Dec 2002 11:48:24 +0000
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On Friday 20 Dec 2002 10:51 am, Philip Warner wrote:
> At 10:21 AM 20/12/2002 +0000, Gary Stainburn wrote:
> >nymr=# select r.*, s.tally from roster r,
> >nymr-#     (select count(*) as tally from roster_staff where
> >nymr(#      rsdate = '2002-01-01' and rsgid = 11 and rsgsid = 2) as s
> >nymr-#   where rodate = '2002-01-01' and rogid = 11 and rogsid = 2;
> >    rodate   | rogid | rogsid | rorequired | rooptional | tally
> >------------+-------+--------+------------+------------+-------
> >  2002-01-01 |    11 |      2 |          0 |          1 |     2
> >(1 row)
>
> Try something like:
>
>      select r.*, count(*) from roster r, roster_staff s
>      where rsdate = rodate and rsgid = rogid and rsgsid = rogid
>      group by r.*

This one came up with a parser error near '*' but I don't understand it enough 
to debug it.

>
> or
>
>      select r.*, (select count(*) from roster_staff s
>      where rsdate = rodate and rsgid = rogid and rsgsid = rogid
>      ) roster r;

This one ran, but the count column had the same value in every row - the total 
count for the table.

I've managed it using an intermediate view.  I've also extended it to show 
everything I need - see below.  I'd still like to hear from anyone who could 
tell me how I can do this without the intermediate view tho'

create table roster ( 	-- roster definition table - holding jobs to be done
rodate		date not null,
rogid		int4 references diagrams(gid),	-- diagram
rogsid		int4 references jobtypes(jid),	-- jobtype
rorequired	int4,				-- essential staff
rooptional	int4,				-- optional staff
primary key (rodate, rogid, rogsid)
);

create table roster_staff ( -- people on the roster
rsdate		date not null,
rsgid		int4 references diagrams(gid),	-- diagram
rsgsid		int4 references jobtypes(jid),	-- jobtype
rssid		int4 references staff(sid),	-- staff id.
constraint r2 foreign key (rsdate,rsgid,rsgsid) references roster 
(rodate,rogid,rogsid)
);

create view roster_tally as
  select rsdate, rsgid, rsgsid, count(*) as rocount
      from roster_staff group by rsdate, rsgid, rsgsid;

create view roster_details as
  select r.*, coalesce(t.rocount,0) as rocount, coalesce(a.rocount,0) as 
roavail
    from roster r
    left outer join roster_tally t on r.rodate = t.rsdate and 
                                      r.rogid = t.rsgid and 
				      r.rogsid = t.rsgsid
    left outer join roster_tally a on r.rodate = a.rsdate and 
                                      a.rsgid is null and 
				      r.rogsid = a.rsgsid;

nymr=# select * from roster_details where rocount < rorequired and roavail > 
0;
   rodate   | rogid | rogsid | rorequired | rooptional | rocount | roavail
------------+-------+--------+------------+------------+---------+---------
 2002-01-01 |    12 |      4 |          1 |          0 |       0 |       1
(1 row)

nymr=#

>
> May not be exactly right, but you should get the idea
>
>
> ----------------------------------------------------------------
> Philip Warner                    |     __---_____
> Albatross Consulting Pty. Ltd.   |----/       -  \
> (A.B.N. 75 008 659 498)          |          /(@)   ______---_
> Tel: (+61) 0500 83 82 81         |                 _________  \
> Fax: (+61) 03 5330 3172          |                 ___________ |
> Http://www.rhyme.com.au          |                /           \|
>
>                                   |    --________--
>
> PGP key available upon request,  |  /
> and from pgp5.ai.mit.edu:11371   |/

-- 
Gary Stainburn
 
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