Re: Concatenating string fields with GROUP BY clause

From: Jeffrey Melloy <jmelloy(at)visualdistortion(dot)org>
To: "Brian G(dot) Huber" <brianghuber(at)yahoo(dot)com>
Cc: "Godshall Michael" <Michael_Godshall(at)gmachs(dot)com>, <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Concatenating string fields with GROUP BY clause
Date: 2003-09-09 17:52:21
Message-ID: 5CCD3A86-E2EE-11D7-A539-000393C78AC0@visualdistortion.org
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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(at)postgresql(dot)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(at)yahoo(dot)com]
> Sent: Tuesday, September 09, 2003 12:02 PM
> To: pgsql-novice(at)postgresql(dot)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
>

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