LINQ: How to find most popular item from column-CodePudding

I want to find which item is most popular in my Orders table with the 'ItemTitle' column.

ItemTitle has the following:

King burger
Hawaiian
Classico Italiano
Tiramisu
King burger
King burger
Classico Italiano
Classico Italiano
King burger

What is the best LINQ query to find which item is most popular? Thank you!

Here is my try:

 return _DbContext.Orders.GroupBy(x => x.ItemTitle).Where(g => g.Count() > 1).OrderByDescending(g => g.Count()).Select(g => g.Key).Take(1);

It's working, however, it has a bug. The bug is Orders has Quantity column. ex: In the list below there are 4 King Burger's x 1 - Quantity. If the Tiramisu has x 10 - Quantity, Now the most popular item should be the tiramisu.

CodePudding user response：

If you don't care about ties, then you can use this:

var query =
    orders
        .GroupBy(x => x.ItemTitle, x => x.Quantity)
        .Select(x => new { ItemTitle = x.Key, Quantity = x.Sum() })
        .OrderByDescending(x => x.Quantity)
        .Take(1)
        .SingleOrDefault();

Otherwise, if tracking ties are important, then this works:

var querySupportingTies =
    orders
        .GroupBy(x => x.ItemTitle, x => x.Quantity)
        .Select(x => new { ItemTitle = x.Key, Quantity = x.Sum() })
        .ToLookup(x => x.Quantity, x => x.ItemTitle)
        .OrderByDescending(x => x.Key)
        .Select(x => new
        {
            Quantity = x.Key,
            ItemTitles = x.ToArray()
        })
        .Take(1)
        .SingleOrDefault();