Re: [SQL] locked my keys in the car

Hello again...

The original post in this thread was - - -

> > What I would like to do is this:
> > SELECT id, MAX(date)
> > FROM table
> > WHERE office='M'
> > AND case='A' OR case='I';

This because, my original (badly formed) query:
SELECT id, date
FROM table
WHERE office='M'
AND case='A' OR case='I';
was returning 48,552 rows...abit more data than I needed...

Thanks to Dave Madden, James Boorn, & Federico Passaro, I reduced this
output to 12,978 rows:

SELECT id, MAX(date)
FROM table
WHERE office='M'
AND case='A' OR case='I'
GROUP BY id;
But this was still problematic, as the rows are patients and
12,978 patients (in a 15 bed ward) is a bit of overcrowding!
(Although we could use the revenue... ;-)

Next I tried Richard Lynch's suggestion:
SELECT id FROM table
WHERE office = 'M' AND (case = 'A' OR case = 'I')
ORDER BY date DESC;

And this is definitely on the right track as I am now down to
75 patients (thanks Rich).

The 13 active cases (in what we loosely term reality) are amongst
the 75 returned tuples.  Moreover, I can catch the 62 inactive cases
listed amongst the output from Rich's query with:

SELECT tr_id, tr_date FROM crtrd1
WHERE tr_unit = 'SMA' AND (tr_type = 'T' OR tr_type = 'O')
ORDER BY tr_date DESC;

(In this instance, T=terminated and O=outgoing...)

So my next question is:
Is there a way, using SQL, to do the math on this, i.e., to rm the
patients who appear twice - once in the first query, once in the second?
(God forbid we re-admit the same patient at some future date!)

In other words, can I somehow go about rm'ing those patients who have
a tr_type of T or O - with a tr_date that is > the tr_date of the entry
with a tr_type of I or A?

We are getting into Byzantine complexities here, SQL wise, and I am
tempted to just dump the output to a (perl) filehandle and let perl
sort the data - but I am curious if SQL can hack it...

Thanks alot,
Tom

    ---------- Sisters of Charity Medical Center ----------
                   Department of Psychiatry
                            ----
    Thomas Good                          <tomg@q8.nrnet.org>
    Coordinator, North Richmond C.M.H.C. Information Systems
    75 Vanderbilt Ave, Quarters 8        Phone: 718-354-5528
    Staten Island, NY   10304            Fax:   718-354-5056