SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function coalesce (alias x) (children 1)
     ExpressionList (children 2)
      Function toNullable (children 1)
       ExpressionList (children 1)
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal UInt64_1
      Literal NULL
    Function toTypeName (children 1)
     ExpressionList (children 1)
      Identifier x
