I am working on a project of a car rental at the moment. I want to create a trigger that will calculate the number of days Between 2 dates. and display it in a new column. So... I realised I need to alter my bookings table because I don't have a duration table. ALTER TABLE bookings ADD The duration varchar(10); After altering, I think I need to create an update trigger because `DATEDIFF` function is used for querying. Could someone help me with this trigger? E.g. Count the amount of days between 10th March and 15th March - 5 days . Any help is appreciated. I'd assume it will be an `UPDATE ` trigger??