cross join

2019-07-31 本文已影响0人 Sam_6155

此句中
SELECT min(a.x-b.x) as shortest
FROM point as a,point as b
WHERE a.x-b.x>0;
等于
SELECT min(a.x-b.x) as shortest
FROM point as a cross join point as b
WHERE a.x-b.x>0;