SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 3)
    Function CAST (alias s) (children 1)
     ExpressionList (children 2)
      Literal \'a\'
      Literal \'Nullable(FixedString(1))\'
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier s
    Function toString (children 1)
     ExpressionList (children 1)
      Identifier s
