SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function dateDiff (children 1)
     ExpressionList (children 3)
      Literal \'day\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Function toDateTime64 (children 1)
         ExpressionList (children 3)
          Literal \'2015-08-18 00:00:00\'
          Literal UInt64_0
          Literal \'UTC\'
      Function toDate (children 1)
       ExpressionList (children 2)
        Literal \'2015-08-19\'
        Literal \'UTC\'