SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 2)
    Function toNullable (alias x) (children 1)
     ExpressionList (children 1)
      Function toDecimal64 (children 1)
       ExpressionList (children 2)
        Literal UInt64_64
        Literal UInt64_0
    Function assumeNotNull (children 1)
     ExpressionList (children 1)
      Identifier x