SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Literal UInt64_10 (alias a)
   ExpressionList (children 1)
    Function plus (alias a) (children 1)
     ExpressionList (children 2)
      Identifier a
      Literal UInt64_1