How can I make change for existing date value in SQL Server into new value?

Does anyone know how can I make change for existing date value in SQL Server into new value?

Example:

Declare @StartDate DATETIME; SET @StartDate = '2010-07-07 00:00:00'

Which I hope to declare another variable @DATETIME2 DATETIME based on @StartDate value c开发者_JAVA百科hanged into '2010-07-07 08:00:00' instead of default manually hard code it

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Use the DateAdd() function:

DECLARE @DateTime2 DateTime; Set @DateTime2 = DATEADD(hh, 8, @StartDate)