Re: Merging 2 rows in a table

2011/1/3 Alexander Farber <alexander(dot)farber(at)gmail(dot)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

>
> Can anybody please help me here?
>
> Thank you
> Alex
>
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