Svenne Krap <[EMAIL PROTECTED]> writes: > create view ord_institutes_sum as > SELECT ord_property_type_all.dataset_id, > ord_property_type_all.nb_property_type_id, 0 AS institut, > sum(ord_property_type_all.amount) AS amount > FROM ord_property_type_all > GROUP BY ord_property_type_all.dataset_id, > ord_property_type_all.nb_property_type_id;
> create view ord_result_pct as > SELECT t1.dataset_id, t1.nb_property_type_id, t1.institut, t1.amount / > t2.amount * 100::numeric AS pct > FROM ord_property_type_all t1, ord_institutes_sum t2 > WHERE t1.dataset_id = t2.dataset_id AND t1.nb_property_type_id = > t2.nb_property_type_id; This is really pretty horrid code: you're requesting double evaluation of the ord_property_type_all view, and then joining the two calculations to each other. No, the planner will not detect how silly this is :-(, nor will it realize that there's guaranteed to be a match for every row --- I believe the latter is the reason for the serious misestimation that Steinar noted. The misestimation doesn't hurt particularly when evaluating ord_result_pct by itself, because there are no higher-level decisions to make ... but it hurts a lot when you join ord_result_pct to some other stuff. It seems like there must be a way to get the percentage amounts with only one evaluation of ord_property_type_all, but I'm not seeing it right offhand. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend