选择集

SelectionSet
  {Selectionlist}
  Selection
Field
  FragmentSpread
  InlineFragment

An operation selects the set of information it needs, and will receive exactly that information and nothing more, avoiding over‐fetching and under‐fetching data.

{
  id
  firstName
  lastName
}

In this query, the id, firstName, and lastName fields form a selection set. Selection sets may also contain fragment references.