Re: [SQL] Join question

I thought of that, but it does violate table constraints.

 

Edward W. Rouse

 

From: Oliveiros Cristina [mailto:oliveiros.cristina@marktest.pt]
Sent: Monday, August 18, 2008 2:00 PM
To: pgsql-sql@postgresql.org; erouse@comsquared.com
Subject: Re: [SQL] Join question

 

I don't understand your count(total) expression...

It doesnt work, because apparently you dont have any "total" column...

Apparently, you meant count(color)

 

The problem is that you are grouping by a.org,a.user and on  table "a" u actually dont have any "null" users...

 

Well, if it is to include "null" users, a quick and dirty solution I can think of would be to add a "dummy" null user to every diferent org on table a and then

substitute your LEFT OUTER JOIN condition by this one :

 

from a left  join b

 

on (a.org = b.org and (a.user = b.user OR (a.user is null and b.user is null )))

 

 

Now, I don' know if "null" users on table "a" will violate any constraints you may have (e.g. NOT NULL) ...

 

I know This is not a very elegant solution, but seems to give the results you need....

 

Best,

Oliveiros

----- Original Message -----

From: Daniel Hernandez

To: pgsql-sql@postgresql.org ; erouse@comsquared.com

Sent: Monday, August 18, 2008 5:30 PM

Subject: Re: [SQL] Join question

 

have you tried a right Join?


Daniel Hernndez.
San Diego, CA.
"The more you learn, the more you earn".
Fax: (808) 442-0427


-----Original Message-----
From: "Edward W. Rouse" [erouse@comsquared.com]
Date: 08/15/2008 09:48 AM
To: pgsql-sql@postgresql.org
Subject: Re: [SQL] Join question

I have 2 tables, both have a user column. I am currently using a left join from table a to table b because I need to show all users from table a even those not having an entry in table b. The problem is I also have to include items from table b with that have a null user. There are some other criteria as well that are simple where clause filters. So as an example:

Table a:

Org|user

A    | emp1

B    | emp1

B    | emp2

B    | emp3

C    | emp2

Table b:

Org|user|color

A   |emp1|red

A   |emp1|blue

A   |null|pink

A   |null|orange

B   |emp1|red

B   |emp3|red

B   |null|silver

C   |emp2|avacado

If I:

select org, user, count(total)

from a left join b

on (a.org = b.org and a.user = b.user)

where a.org = 'A'

group by a.org, a.user

order by a.org, a.user

I get:

Org|user|count

A    |emp1|2

A    |emp2|0

A    |emp3|0

But what I need is:

A    |emp1|2

A    |emp2|0

A    |emp3|0

A    |null|2

Thanks,

Edward W. Rouse