SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function dateDiff (children 1)
     ExpressionList (children 3)
      Literal \'second\'
      Function toDateTime64 (children 1)
       ExpressionList (children 3)
        Literal \'2015-08-18 00:00:00\'
        Literal UInt64_0
        Literal \'UTC\'
      Function toDateTime (children 1)
       ExpressionList (children 2)
        Literal \'2015-08-18 01:00:00\'
        Literal \'UTC\'