Linq Find the most recurring record

I have a rent a car project. This is the table where I keep the rented vehicles I want to find the most rented vehicle in this table. How can I do this? So I want to find the most mentioned car Id in the table [I have to do it with context architecture. How can I do this with c # linq?]2

Answer

I want to find the most rented vehicle in this table.

So basically you want to find out how many times car 5 is rented, and how many times car 6 is rented, etc, and keep the carId with the highest rental count.

As you are working with a database, my advice would be to use GroupBy to make groups of rentals that have the same CarId, and then keep the group that has the most number of rentals = order by descending count and take the first.

We’ll use the overload of Queryable.GroupBy that has a parameter resultSelector, so we can select the number of rentals in the group as result.

// make groups of CarRentals that have the same CarId:
var mostRentedCarId = dbContext.CarRentals.GroupBy(carRental => carRental.CarId,

// parameter resultSelector: for every CarId and all CarRentals that have this CarId,
// make one new object
(carId, carRentalsWithThisCarId) => new
{
    CarId = carId,
    RentalCount = carRentalsWithThisCarId.Count(),
})

// order the groupBy result by descending rentalCount and take the first or default:
.OrderByDescending(groupByResult => groupByResult.RentalCount)
.FirstOrDefault();