How do I get the total number of seconds between two dates?
You can use the DATEDIFF function to calculate the difference between two dates. The value can be returned in years, quarter, months, days, weeks, minutes, seconds and so on. This syntax returns the difference between today and yesterday in seconds:
SELECT DATEDIFF(ss, '06/29/00', '06/30/00') AS Seconds
Remember, if you're using datetime variables or GETDATE() it will calculate using both the date and time stored in each variable.