A statue is always a sculpture but a sculpture is not always a statue. OK, both are 3d in nature and both can be made from many different materials. The difference is that a sculpture can be depicting anything, any thoughts, any ideas, while a statue is a realistic image of a living thing, usually the human figure. When you look at a sculpture you don’t necessarily know what it is depicting while when you look at a statue you know immediately that it is a human figure, or a dog, or a tree.
The attached picture is a great example of sculptures and statues. The center sculpture is a bronze sculpture created by Kevin Robb titled “Radical 2” and is fabulous as a focal point in this garden. The statues surrounding the pool are human figures. The design of this garden is a fun example of utilizing both.
Just having fun with the English language, you can sculpt (verb) and work as a sculptor (noun) but you certainly can’t stat(verb ??) and work as a stator (noun ???)