What's the difference between the world number one badminton player and the world champion?

Ranked first in the world, only professional players are eligible to participate in major professional competitions, and then earn points by ranking. World champion is to win the championship in world-class events, such as the World Championships and the Olympic Games. Being number one in the world doesn't mean being a world champion. Li Zongwei and Dānlín are. Li Zongwei has never won a world championship, but his points are the first in the world.