Puzzles and SQL questions
1. On an Island, there is an airport that has an unlimited number of identical air-planes. Each air-plane has a fuel capacity to allow it to fly exactly 1/2 way around the world, along a great circle. The planes have the ability to refuel in flight without loss of speed or spillage of fuel. Though the fuel is unlimited, the island is the only source of fuel. You can ignore the time and fuel consumption of refuelling.
What is the minimum number of air-planes required to get one air plane all the way around the world assuming that all of the air planes must return safely to the airport?
2.Suppose you’re on a game show, and you’re given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what’s behind the doors, opens another door, say No. 3, which has a goat. He then says to you, “Do you want to pick door No. 2?” Is it to your advantage to switch your choice?
3).in SQL founder have idea about join.
