SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 3)
    Identifier ts
    Identifier metric
    Function nonNegativeDerivative (alias deriv) (children 1)
     ExpressionList (children 3)
      Literal \'string not datetime\'
      Identifier ts
      Function toIntervalNanosecond (children 1)
       ExpressionList (children 1)
        Literal UInt64_3
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier nnd