Selection set without entity fields returns an error response for GraphQL query and mutation

[severussundar]

For the below query and mutations, an error response is returned

Query:

{
    book_by_pk(id: 1){
         __typename
     }
}

Mutation:

mutation {
     updatebook(id: 1, item: {title: "Another great book"}){
        __typename  
     }
}

Root Cause:
The SELECT query is constructed without any column. This leads to failure at the database layer.

Since, there are no entity fields in the selection set, the flow should not go to the database layer.