MySQL Expert required for 4 easy tasks

I need an expert in MySQL. I have 4 tasks for MySQL: 2 are queries, 1 function and 1 procedure. (For details/instructions send me a private message. I expected real bid after reading instructions.) This is NOT for collegue is for a project - The solutions needs to be Effective and Efficient, Each solution needs to be commented/explained: what is doing?, and why you choose that implementation? Easy for someone with experience.