Shortest Distance in a Plane
这里要用round，sqrt和pow三个函数才行
SELECT ROUND(MIN(SQRT(POW(p1.x - p2.x, 2) + POW(p1.y - p2.y, 2))), 2) AS shortest
FROM point_2d p1
JOIN point_2d p2
ON (p1.x <> p2.x) OR (p1.y <> p2.y)
这里要用round，sqrt和pow三个函数才行
SELECT ROUND(MIN(SQRT(POW(p1.x - p2.x, 2) + POW(p1.y - p2.y, 2))), 2) AS shortest
FROM point_2d p1
JOIN point_2d p2
ON (p1.x <> p2.x) OR (p1.y <> p2.y)