GraphQL API plugged into the old MySQL database of JeuxAmateurs (French website about amateur games).
Disclaimer: This was an experimentation to understand better how you can easily build a GraphQL schema using available tools. Of course, it isn't very optimized at all but I hope with this you can be inspired.
Load structure.sql, fill it with data and run npm install && npm start. Here's your GraphQL API!. Note that the structure is old and ugly, for testing and posterity only!
GraphQL comments above the line can be used for documenting directly. Take a look at this:
# My awesome type
type User {
# This is a username
username: String!
# I shouldn't have exposed this
password: String!
}And the result in the GraphiQL editor: 
.
Yes it is possible and it means that the array shouldn't be null when you query it.
So [Type]! means you always get an array (empty or not), [Type!] is for a non-empty array or null, [Type!]! is always a non-empty array. Fun!