SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function age (children 1)
     ExpressionList (children 3)
      Literal \'second\'
      Function toDateTime (children 1)
       ExpressionList (children 3)
        Literal UInt64_1157339245694594829
        Literal UInt64_6
        Literal \'UTC\'
      Function toDate (children 1)
       ExpressionList (children 1)
        Literal \'2015-08-18\'