How To Set Different Parts of a DATETIME Value in SQL Server Transact-SQL?

In SQL Server, you can get different parts of a DATETIME value with the DATEPART() functions. But there is no function that allows you to set different parts to a DATETIME value. For example, you a date_of_birth column as DATETIME in a table, you want to set all rows to the noon time in this column.

The tutorial exercise below shows how to set year, month, day, hour, minute and second to any give DATETIME value:

-- set parts to a DATETIME value
DECLARE @date_of_birth DATETIME;
SET @date_of_birth = GETDATE();
SET @date_of_birth = DATEADD(YEAR, 
   1987-DATEPART(YEAR,@date_of_birth), @date_of_birth);
SET @date_of_birth = DATEADD(MONTH, 
   05-DATEPART(MONTH,@date_of_birth), @date_of_birth);
SET @date_of_birth = DATEADD(DAY, 
   19-DATEPART(DAY,@date_of_birth), @date_of_birth);
SET @date_of_birth = DATEADD(HOUR, 
   12-DATEPART(HOUR,@date_of_birth), @date_of_birth);
SET @date_of_birth = DATEADD(MINUTE, 
   00-DATEPART(MINUTE,@date_of_birth), @date_of_birth);
SET @date_of_birth = DATEADD(SECOND, 
   00-DATEPART(SECOND,@date_of_birth), @date_of_birth);
SELECT 'You were born on '
   + CONVERT(VARCHAR(40),@date_of_birth,107)
   + ', at '
   + CONVERT(VARCHAR(40),@date_of_birth,108);
GO
You were born on May 19, 1987, at 12:00:00

⇒ Working with NULL Values in SQL Server Transact-SQL

⇐ Truncating DATETIME Values to Dates without Time in SQL Server

⇑ Date/Time Operations and Functions in SQL Server Transact-SQL

⇑⇑ SQL Server Transact-SQL Tutorials