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Re: How do you do the opposite of regexp_split_to_table? - Mailing list pgsql-sql

From Alvaro Herrera
Subject Re: How do you do the opposite of regexp_split_to_table?
Date
Msg-id 1280867576-sup-2555@alvh.no-ip.org
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In response to How do you do the opposite of regexp_split_to_table?  (John Gage <jsmgage@numericable.fr>)
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Excerpts from John Gage's message of mar ago 03 16:21:58 -0400 2010:

> Grouping by summing numerical fields seems to be straightforward, but  
> grouping by concatenating text fields escapes my search of the  
> documentation.

You can create a new custom aggregate function that does this.  It's
pretty straightforward.  There are examples in the archives (search for
text_concat), but there's also a more modern way involving array_agg and
array_to_string.

-- 
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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