I am experiencing the following problem;

I boot my Windows 2000 sp#4 machine. I check sqlservr.exe's memory usage in
Task manager. It is ca 20 mb, everything is OK. Then I run this query;

select postoffice, count(*) as counter from tblTable
where postoffice is not null
group by postoffice
order by counter DESC

There's no index or constraint on field "postoffice" and tblTable contains
ca 916.000 rows. I thought this query would still execute in only a few
seconds, but it takes minutes. And the worst thing is that sqlserver.exe's
memory usage grows to about 300-400 mb when the query runs. What am I doing
wrong??

Tnx in advance!

/Magnus