how to subtract two time in sql server?

Question

So I don't know how to subtract two time(hh:mm:ss) in sql server.

This is my statement:

where   
 ( CONVERT(TIME(7), [EndWork], 102)) - ( CONVERT(TIME(7), [StartWork], 102)) <
 CONVERT(TIME(7), ' 8:30:00', 102)

Answer 1

DECLARE @END_DATE TIME = '' ,    
     @START_DATE  TIME = ''
     SELECT CONVERT(TIME,DATEADD(MS,DATEDIFF(SS, @START_DATE, @END_DATE )*1000,0),114)