10. 性能比較 その1
平均値の算出
select avg(arrdelay) from flights where origin_point @ ST_MakeEnvelope(20, -160, 50, -80, 4326);
select avg(arrdelay) from flights where origin_lon between -160 and -80 and origin_lat between 20 and 50;
空間インデクスが
ない場合は32秒
空間インデクス
なし
11. 性能比較 その2
GROUP BY
select uniquecarrier, count(*), avg(arrdelay) from flights where origin_point @ ST_MakeEnvelope(20, -160, 50, -80,
4326) group by uniquecarrier;
select uniquecarrier, count(*), avg(arrdelay) from flights where origin_lon between -160 and -80 and origin_lat
between 20 and 50 group by uniquecarrier;
空間インデクスが
ない場合は61秒
空間インデクス
なし