Not wanting to be awkward or anything, but ... Paul Makepeace wrote:
On Wed, Jan 29, 2003 at 12:10:38PM +0000, the hatter wrote:... I have seen cases (under Informix and MySQL) where the use of an OR clause causes a sequential scan of the entire table. With a largish table under production load, the results are... interesting.
On Wed, 29 Jan 2003, Paul Makepeace wrote:
So there are a bunch of things "order by rank". I'd like to implement a$query = "UPDATE fw SET rank=rank+(-2*(rank-($position+0.5))) WHERE ";
move up/down in SQL. So say the target was id=20 moving up, I'd like its
rank to become 1, and id=10's rank to become 2.
$query .= "(rank=$position OR rank=$position+1)"
You might want to check that Postgres doesn't do that (using whatever its EXPLAIN functionality is).
Cheers
Ti'
