SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 2)
    Identifier v
    Function variantElement (children 1)
     ExpressionList (children 2)
      Identifier v
      Literal \'Tuple(a UInt64, b UInt64)\'
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      Function format (children 1)
       ExpressionList (children 3)
        Identifier JSONEachRow
        Literal \'v Variant(String, Tuple(a UInt64, b UInt64))\'
        Literal \'{"v" : null}, {"v" : "string"}, {"v" : {"a" : 42, "b" : null}}, {"v" : {"a" : 44, "d" : 32}}\'
   Set
