Answer by Rwd for How To Add Interval 30 Days in Laravel (MYSQL)

The reason you're not getting the results you want is because you're using where instead of whereRaw. In this case your query going to return:

select * from `projects` where end_date BETWEEN     CURRENT_DATE() AND DATE_ADD(CURRENT_DATE(), INTERVAL 30 DAY) is null

(notice the is null part).

To get the results you want change where to whereRaw (you can remove the DB::raw):

project::whereRaw('end_date BETWEEN CURRENT_DATE() AND DATE_ADD(CURRENT_DATE(), INTERVAL 30 DAY)')->get();

Alternatively, you could use a mixture of whereBetween and Carbon:

project::whereBetween('end_date', [now(), now()->addDays(30)])->get();

Check out this answer for more information.