problems with SELECT query results

Joshua wrote:

Hello,

I am new to this list and have been working with PostgreSQL since January.

Here is my problem, I hope someone here has some experience or can point
me in the right direction. I am writing the following query for a C#
program I am writing:

SELECT 'PV.LINEITEM:' || partnum || ',' || round(onhand) || ',' ||
round(qm5) || ',' || round(lsm4) || ',' || ',' || ',' || round(onorder)
|| ',' || ',' || ',' || binone || ',' || ',' || round(backorderqty) ||
',' || ',' || round(onhold) || ',' || ',' || ',' || ',' || ',' || ',' ||
',' || round(qtyperjob) || ',' || round(ordermax) AS gmrim FROM slparts
WHERE vendor LIKE 'CH%'

The query does work and I am getting results from the database. There
are values for all 'partnum' in the database, however, the query results
include blank fields here and there in between the returned records. Why
am I receiving blank fields for 'gmrim'???? This absolutely defies logic
and I cannot find any rhyme or reason for this problem. I cannot have
any blank rows in the query, and again the database is completely
populated with values.

I'm not sure it is - I think you've got a NULL somewhere.

Since NULL means "unknown" ('text' || NULL) = NULL

Wrap all your column-references in COALESCE: e.g. COALESCE(partnum,'')
and see if that solves it. If so, go back and find rows WHERE partnum IS
NULL and correct them. Then set the NOT NULL constraint on the relevant
columns.

--
Richard Huxton
Archonet Ltd

Hello,

Thank you all for your assistance. I did end up finding NULL in the
'onorder' column which should have been zero's.... this was in a test
table that happened to have some NULL in it for one reason or another
but I should not find this in the production version of the table.

I also appreciate you pointing out the COALESCE function. I will find
that helpful in future work.

I look forward to hopefully assisting you guys with some of your
PostgreSQL dilemmas in the future!

Thanks again!!!

-Joshua

Richard Huxton wrote:

Joshua wrote:

Thank you all for your assistance. I did end up finding NULL in the
'onorder' column which should have been zero's.... this was in a test
table that happened to have some NULL in it for one reason or another
but I should not find this in the production version of the table.

I also appreciate you pointing out the COALESCE function. I will find
that helpful in future work.

I look forward to hopefully assisting you guys with some of your
PostgreSQL dilemmas in the future!

Please do not top-post, and be sure to acknowledge both groups to whom you
multi-posted, pgsql.sql and pgsql.general, for their help. (I don't know if
there were others.)

A more effective way to post to multiple groups is to cross-post, send to all
groups in the single message as I did here, which unifies the threads so that
all answers appear to each reader.

Multi-posting (sending to each group separately) is frustrating because it
fragments the conversation.

--
Lew

--- Joshua <joshua@joshuaneil.com> wrote:

Hello,

Thank you all for your assistance. I did end up finding NULL in the
'onorder' column which should have been zero's.... this was in a test
table that happened to have some NULL in it for one reason or another
but I should not find this in the production version of the table.

If this should be allowed to have nulls, you should add a not null constraint to your table to
prevent this sort of thing from happening. If a field should have zero's instead of nulls, you
should also add a default value of zero for this column.

ALTER TABLE Slparts
ALTER COLUMN onorder SET NOT NULL,
ALTER COLUMN onorder SET DEFAULT 0;

Regards,
Richard Broersma Jr.