Merging 2 rows in a table

2011/1/3 Alexander Farber <alexander.farber@gmail.com>:

Hello,

through some obscure error (probably on my side)
I have several thousand entries for Jan 1 and Jan 2
ending up in the ISO week 2011-52 instead of 2010-52
which breaks the bar chart at the top of my script
http://preferans.de/user.php?id=OK504891003571

# select * from pref_money where id='OK324712148886';
      id       | money |   yw
----------------+-------+---------
 OK324712148886 |   203 | 2010-46
 OK324712148886 |   219 | 2010-49
 OK324712148886 |   115 | 2010-51
 OK324712148886 |    63 | 2010-52
 OK324712148886 |    20 | 2011-01
 OK324712148886 |    10 | 2011-52

# \d pref_money
                       Table "public.pref_money"
 Column |         Type          |                Modifiers
--------+-----------------------+-----------------------------------------
 id     | character varying(32) |
 money  | integer               | not null
 yw     | character(7)          | default to_char(now(), 'YYYY-IW'::text)
Indexes:
   "pref_money_yw_index" btree (yw)
Foreign-key constraints:
   "pref_money_id_fkey" FOREIGN KEY (id) REFERENCES pref_users(id)

I would like to fix that problem by adding
2011-52 values of money (10 above) to the
2010-52 values of money (63 above, should become 73)
and then dropping all rows with the
wrong week number yw='2011-52'.

So I'm trying:

# update pref_money set money=money+
   (select money from pref_money where yw='2011-52')
   where yw='2010-52';
ERROR:  more than one row returned by a subquery used as an expression

ok, I probably need to specify the id for the subquery
in round brackets above - so I try again:

# update pref_money as m1 set money=money+
(select coalesce(money,0) from pref_money as m2
where m1.id=m2.id and m2.yw='2011-52')
where m1.yw='2010-52';
ERROR:  null value in column "money" violates not-null constraint

update tab set money = money + COALESCE((SELECT ...) , 0) ..

Regards

Pavel Stehule

Thank you Pavel, has worked:

# update pref_money as m1 set money=money+coalesce((select money from
pref_money as m2 where m1.id=m2.id and m2.yw='2011-52'),0) where
m1.yw='2010-52';
UPDATE 2081

On 2011-01-03, Alexander Farber <alexander.farber@gmail.com> wrote:

Hello,

through some obscure error (probably on my side)

Column | Type | Modifiers
--------+-----------------------+-----------------------------------------
id | character varying(32) |
money | integer | not null
yw | character(7) | default to_char(now(), 'YYYY-IW'::text)

'YYYY-IW' above should be 'IYYY-IW'

(you may have made a similar mistake in other places too.)

I have several thousand entries for Jan 1 and Jan 2
ending up in the ISO week 2011-52 instead of 2010-52
which breaks the bar chart at the top of my script
http://preferans.de/user.php?id=OK504891003571

I would like to fix that problem by adding
2011-52 values of money (10 above) to the
2010-52 values of money (63 above, should become 73)
and then dropping all rows with the
wrong week number yw='2011-52'.

perhaps something like this:

update pref_money as dat set money=dast.money+ foo.money from
pref_money as foo where dat.id=foo.id
and dat.yw='2011-52'
and foo.yw ='2012-52' ;

--
⚂⚃ 100% natural

This explains my problem, thanks!