On 03.12.2010 23:53, Oleg Bartunov wrote:
> create table qq (b box);
> CREATE TABLE
> select count(*), b from qq group by b;
> ERROR: could not identify an equality operator for type box
> LINE 1: select count(*), b from qq group by b;
>
> but following select works fine
>
> select ' (43.6038,48.8664536),(1.3620777,1.44327)'::box = '
> (43.6038,48.8664536),(1.3620777,1.44327)'::box;
> ?column? ----------
> t
> (1 row)
> ^
> What does it means ?
GROUP BY requires b-tree sort operators. Although there is a '='
operator for box, there is no b-tree opclass.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com