Alban Hertroys skrev:
> Nis Jørgensen wrote:
>> If you can't wait, you are probably better off working around the
>> problem. Standard solution is to do:
>>
>> UPDATE  master SET m2 = -m2;
>> UPDATE  master SET m2 = -m2+1;
>>
>> or something similar.
> 
> Would something like
> 
> UPDATE master set m2 = master2.m2
>   FROM (
>       SELECT m2 +1
>         FROM master m
>        WHERE m.master_id = master.master_id
>        ORDER BY m2 DESC
>  ) master2
> 
> work? I think it might be faster (and possibly cause less index bloat)
> than doing two consequent updates.


I don't understand your query. I don't think you can use a correlated
subquery in that way.

Anyway, tricks like these might work. They might stop working without
warning, if the plan changes. Relying on unspecified behavior is a
recipe for trouble.

Nis



---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster

Reply via email to