hi

I was wondering if it is possible to add a formula in mysql?
like for example if i want to generate and automatic ID but this ID must contain lets say 1st 3 letters of the username and year he joined

If this ID is just composed from pieces of the other columns, then there is no point creating it as a new column since that information is already in the database. In this case the username and date of joining are both 'candidate keys' which together provide a (possibly) unique ID.

If you were to want to select based on this id, then you could do something along the lines of

SELECT CONCAT(SUBSTR(username,1,3),date_joined)) from users;

ill try this ..

but will the same work in MS SQL Server?

should do.

It's ANSII SQL rather than MySQL specific