UPDATE with ORDER BY

Question

Need to "tie" UPDATE with ORDER BY. I\'m trying to use cursors, but get the error:

cursor "cursupd"         


        

Answer 1

If anyone comes here just like I came for the problem with rearranging the postgresql table_id_seq from 1 and order by the id. The solution I tried was partially taken from @Syd Nazam Ul Hasan (above) and https://gist.github.com/JoshCheek/e19f83f271dc16d7825e2e4079538ba8.

CREATE OR REPLACE FUNCTION update_sequence()
RETURNS SETOF varchar AS $$
DECLARE
  curs CURSOR FOR SELECT * FROM table ORDER BY id ASC;
  row  RECORD;
  v INTEGER := 0;
BEGIN
  open curs;
  LOOP
    FETCH FROM curs INTO row;
    update table 
    set id = v+1
    where id = row.id;
    v = v+1;
    EXIT WHEN NOT FOUND;
    return next row.id;
  END LOOP;
END; $$ LANGUAGE plpgsql;

SELECT update_sequence();