Re: Concatenating string fields with GROUP BY clause

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

From: Jeffrey Melloy

To: Brian G. Huber

Cc: Godshall Michael ; pgsql-novice@postgresql.org

Sent: Tuesday, September 09, 2003 12:52 PM

Subject: Re: [NOVICE] Concatenating string fields with GROUP BY clause

I think what he's trying to do is this:
a | b | g
1 | sun | 1
2 | shoe | 1
3 | pea | 2
4 | door | 2

he gets this as the response:
group, sum, concat
1, 3, sunshoe
2, 7, peadoor

So a "concatenation aggregate"

That being said, I can't think of any simple way to do it in SQL.

Jeff
On Tuesday, September 9, 2003, at 12:29 PM, Brian G. Huber wrote:

Thanks for the response - but II does not seem to work as an aggregate function - for example - if I use:
 
SELECT groupid, sum(numeric_field), ||(text_field) FROM table GROUP BY groupid
 
I get
 
ERROR:  Unable to identify a prefix operator '||' for type 'text'
 You may need to add parentheses or an explicit cast
 
Therefore, I think II concatenates two text columns, but does not aggregate.  It would seem this is fairly common but there is no text aggregation function listed in 6.14 Aggregate Functions!!!
----- Original Message -----

From: Godshall Michael
To: 'Brian G. Huber' ; pgsql-novice@postgresql.org
Sent: Tuesday, September 09, 2003 12:10 PM
Subject: Re: [NOVICE] Concatenating string fields with GROUP BY clause

Concatenate is done with  ||   in postgresql

-----Original Message-----
From: Brian G. Huber [mailto:brianghuber@yahoo.com]
Sent: Tuesday, September 09, 2003 12:02 PM
To: pgsql-novice@postgresql.org
Subject: [NOVICE] Concatenating string fields with GROUP BY clause

Hi -
 
I am trying to concatenate a text field in a query with a group by clause, similar to a sum() function on a numeric value - for example:
 
SELECT groupid, sum(numeric_field), ???(text_field) FROM table GROUP BY groupid
 
but I cannot find a function that will concatenate the text fields. Any comments appreciated!
 
TIA,BGH