Re: getting count for a specific querry

Ragnar Hafstað <gnari@simnet.is> writes:
> you might reduce the performance loss if your dataset is ordered by
> a UNIQUE index.

> select * from mytable where somecondition 
>                       ORDER by uniquecol limit 50;

> and next:

> select * from mytable where somecondition AND uniquecol>? 
>                       ORDER by uniquecol limit 50 OFFSET 50;

> where the ? is placeholder for last value returned by last query.

Uh, you don't want the OFFSET there do you?  But otherwise, yeah,
this is a popular solution for paging through some rows.  Doesn't really
help with the problem of counting the total dataset though ...
        regards, tom lane