>> try this:
>> select mytime from mytable order by abs(extract(epoch from
>> (usertime-mytime))) asc limit 5;
>> SELECT ts_fld2,abs(extract(epoch from '2011-03-25
>> 14:15:25-07'::timestamptz)-extract(epoch from ts_fld2)) from timestamp_test order
>> by abs(extract(epoch from '2011-03-25 14:15:25-07'::timestamptz)-extract(epoch
>> from ts_fld2)) limit 5;
Thanks to Ondrej and Adrian, who both provided working solutions using extract/epoch.