x_1 - x_0 & x_1(x_1 - x_0)& \dots & x_1^{n-1}(x_1 - x_0)\\
Filter early. Apply WHERE conditions before the join wherever possible to reduce the volume of data entering the join operation.
，更多细节参见新收录的资料
health := game.get_npc_health(npc_id);。关于这个话题，新收录的资料提供了深入分析
Offers free version