Re: Renumber table rows - Mailing list pgsql-general

From Efraín Déctor
Subject Re: Renumber table rows
Date
Msg-id 428552E443704946AFB814B29A9951EB@CMOTUM25PC
Whole thread Raw
In response to Re: Renumber table rows  ("David Johnston" <polobo@yahoo.com>)
List pgsql-general
Thank you. It really worked.
 
Sent: Wednesday, June 06, 2012 3:17 PM
Subject: RE: [GENERAL] Renumber table rows
 

 

Try something along the lines of:

 

UPDATE operador SET idoperador = new_idoperador

FROM (

                SELECT idoperador AS old_idoperador, ROW_NUMBER() OVER (ORDER BY idoperador) AS new_idoperador

                FROM operador

) lookup

WHERE operador.idoperador = lookup.old_idoperador;

 

The basic ideas is to create a lookup table and use it in via a FROM clause attached to the UPDATE.

 

David J.

 

 

From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Efraín Déctor
Sent: Wednesday, June 06, 2012 2:27 PM
To: pgsql-general@postgresql.org
Subject: [GENERAL] Renumber table rows

 

Hello.

 

I have a table that his primary key is not ordered is something like this:

 

1      - a

12    - b

123  - c

etc.

 

I want to do an update to make it like this

 

1 – a

2 – b

3 – c

 

I tried this:

 

UPDATE operador SET idoperador=(SELECT row_number() OVER (ORDER BY idoperador) from operador)

 

But it returns this error: more than one row returned by a subquery used as an expression and I know that is because the substring returns more than one row, but how can I use the subquery to perform the update?.

 

Thank you in advance

 

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