Re: SQL Join - MySQL/PostgreSQL difference?

Here's some more details:

The following query:

SELECT * FROM tblpemdruglink WHERE drugid = 'DG-5039';

returns the following results:

drugid | monographid
---------+-------------
DG-5039 | 2008
(1 row)

the following query:

SELECT * FROM tblfdbmono WHERE
monographid='2008' AND
versionid='FDB-PE' AND
category='PEM';

returns the following results:

versionid | category | monographid | sequencenumber | sectioncode |
linetext
-----------+----------+-------------+----------------+-------------+---------------------------------------------------------------------
{content}

sorry, the {content} is what's under NDA :(

In any case, you can see the structure of the tables tblpemdruglink and
tblfdbmono from here.

Now the following query:

SELECT sequencenumber,sectioncode,linetext
FROM tblfdbmono fdb, tblpemdruglink pem WHERE
fdb.monographid=pem.monographid AND
fdb.versionid='FDB-PE' AND
fdb.category='PEM' AND
pem.drugid='DG-5039';

Should return the same results as the second query above. However, this
is what I get:

sequencenumber | sectioncode | linetext
----------------+-------------+----------
(0 rows)

And it takes about 3-4 seconds to return with that prognosis. What's
going on here?

-Brice

Peter Eisentraut wrote:
>
> Brice Ruth writes:
>
> > SELECT
> > a.Number,
> > a.Code,
> > a.Text
> > FROM
> > b,
> > a
> > WHERE
> > (b.Id = a.Id) AND
> > (VersionId = 'key1') AND
> > (Category = 'key2') AND
> > (b.d_Id = 'key3')
> > ORDER BY
> > a.Number;
> >
> > (my apologies: I had to 'mangle' the table/column names because of NDA)
> >
> > So my question is this: would this query operate differently in MySQL
> > than in PostgreSQL? The reason I ask is that this query in MySQL
> > returns results, yet in PostgreSQL it does not.
>
> Without showing the tables and the data in it, it's fairly hard to tell.
> I think MySQL does case insensitive string comparisons; check that.
>
> > I read a post about PostgreSQL not supporting outer joins, but I don't
> > have enough experience with SQL to determine if this is such a query
> > or not. Please advise.
>
> This is not an outer join.
>
> --
> Peter Eisentraut peter_e(at)gmx(dot)net http://yi.org/peter-e/

--
Brice Ruth
WebProjkt, Inc.
VP, Director of Internet Technology
http://www.webprojkt.com/