ASP.NET LINQ to SQL eight words

Eight words:

From ...in clause: The data source and scope variables to perform the query operation on

var q =
    from c in db.Customers
    from o in c.Orders
    where c.City == "London"
    select o;

Select clause: specify the type and representation of query results

var q =
    from c in db.Customers
    select c.ContactName;

Where clause: Logical conditions for filtering elements, generally composed of logical operators

var q =
    from c in db.Customers
    where c.City == "London"
    select c;

Example: Use where to filter customers in London

var q =
    from c in db.Customers
    where c.City == "London"
    select c;

Group...by clause: group the query

var q =
    from p in db.Products
    group p by p.CategoryID into g
    select g;

Orderby clause: Sort the query results, which can be divided into descending order and ascending order.

var q =
    from c in db.Customers
    orderby c.City, c.ContactName
    select c;

Join clause: joins data sources for multiple query operations

var q =
    from e in db.Employees
    join o in db.Orders on e equals o.Employee into ords
    from o in ords.DefaultIfEmpty()
    select new
    {
        e.FirstName,
        e.LastName,
        Order = o
    };

Let Clause: Introduce scope variables for storing the results of subexpressions in query expressions

var query =
                from sentence in strings
                let words = sentence.Split(' ')//Split into arrays with spaces
                from word in words
                let w = word.ToLower()// Lowercase each letter
                where w[0] == 'a' || w[0] == 'e'
                select word;

Into clause: Provides a temporary identifier that acts as a result of a join, group or select clause

var byHow = from how in  vehicles

                        join trans in transports

                        on how.vehicleHow equals trans.How

                        into lst // this lst is of type IEnumerable<transport>

                        select new { How=how, Tlist = lst };