This is my solution.

SET DATEFORMAT mdy;

DECLARE @PersonTime TABLE

(

ID INT,

Person INT,

Room INT,

Coming DATETIME,

Going DATETIME

);

INSERT INTO @PersonTime

SELECT 1, 1001, 23, '10/13/2014 8:00:00', '10/13/2014 9:00:00' UNION ALL

SELECT 2, 1002, 23, '10/13/2014...

Hello serg-52,

thank you for your answer.

It looks ... strange und i don't understand the algorithm at the moment, but the result for room 24 is wrong.