"Craig A. James" <cjames@modgraph-usa.com> writes:
> MIN() and MAX() -- These are surprisingly slow, because they seem to do a full table scan EVEN ON AN INDEXED COLUMN!
Idon't understand why, but happily there is an effective substitute:
> select mycolumn from mytable order by mycolumn limit 1; -- same as MIN()
> select mycolumn from mytable order by mycolumn desc limit 1; -- same as MAX()
BTW, Postgres does know to do that for itself as of 8.1.
regards, tom lane
