SQL：指向矩形的点列表

Question

我有两张桌子：

regions <id>
points <region_id, x, y>

假设每个区域正好有4个点，而这些点描述了一个矩形 - 是否有一个SQL查询会给我带来这个视图：

rectangular_regions <region_id, x1, y1, x2, y2>

Answer 1

SELECT region_id, MIN(x) AS x1, MIN(y) AS y1, MAX(x) AS x2, MAX(y) AS y2 
FROM points 
GROUP BY region_id.