Truncate Datetime to Second (Remove Milliseconds) in T-SQL

Question

What is the best way to shorten a datetime that includes milliseconds to only have the second?

For example 2012-01-25 17:24:05.784 to 2012-01-25

Answer 1

--- DOES NOT Truncate milliseconds
--- 2018-07-19 12:00:00.000
SELECT CONVERT(DATETIME, '2018-07-19 11:59:59.999')  

--- Truncate milliseconds
--- 2018-07-19 11:59:59.000
SELECT CONVERT(DATETIME, CONVERT(CHAR(19), '2018-07-19 11:59:59.999', 126)) 

--- Current Date Time with milliseconds truncated
SELECT CONVERT(DATETIME, CONVERT(CHAR(19), GETDATE(), 126))