CODEWITHSUNDEEP
c#linqlinq-to-entities
RTRokzzz
RTRokzzz

Reputation: 235

LINQ error - The method 'Sum' is not supported

I am having following linq -

var quantity = (from p in context.StoreInventory
                         where p.BookId== BookId
                                && p.StoreAddress == StoreAddress
                         select p).Sum(i => i.Quantity);

I am getting error -

The method 'Sum' is not supported

Can anyone tell me the reason and required changes.

Upvotes: 4

Views: 1603

Answers (2)

Adil
Adil

Reputation: 148180

Use Enumerable.ToList before you call Sum to convert the query to collection.

var quantity = (from p in context.StoreInventory
                         where p.BookId== BookId
                                && p.StoreAddress == StoreAddress
                         select p).ToList().Sum(i => i.Quantity);

Edit: This will bring all the row and will apply the sum which is not efficient way of doing. As you need to sum up quantity you can select quanity instead of row. 

var quantity = (from p in context.StoreInventory
                         where p.BookId== BookId
                                && p.StoreAddress == StoreAddress
                         select p.Quantity).Sum();

Upvotes: 3

MarcinJuraszek
MarcinJuraszek

Reputation: 125660

var quantity = (from p in context.StoreInventory
                         where p.BookId== BookId
                                && p.StoreAddress == StoreAddress
                         select p.Quantity).Sum();

This should work - the sum is performed on 'Quality' column, which is taken using select statement. That's because Sum(expression) is not supported by LINQ to Entities, but standard Sum() is.

Whole work should be done by database, so no rows will be retrieved by application - just single number.

Upvotes: 11

Related Questions