вроде все заработало:
SELECT TOP 1 * FROM [arch_to_report].[dbo].[Values] ORDER BY Timestamp ASC SELECT * FROM [arch_to_report].[dbo].[Values] WHERE Timestamp>@Начало AND Timestamp<@Конец - Первое значение
SELECT TOP 1 * FROM [arch_to_report].[dbo].[Values] ORDER BY Timestamp DESC SELECT * FROM [arch_to_report].[dbo].[Values] WHERE Timestamp>@Начало AND Timestamp<@Конец - Последнее значение
