Learn Linq query in c#

Filtering
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var queryLondonCustomers = from cust in customers
                           where cust.City == "London" 
                           select cust;

 
queryLondonCustomers.Where(p=>p.Cust_code>50)

Ordering

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var queryLondonCustomers3 = 
    from cust in customers
    where cust.City == "London" 
    orderby cust.Name ascending 
    select cust;

Grouping

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 var queryCustomersByCity =
      from cust in customers
      group cust by cust.City;

  // customerGroup is an IGrouping<string, Customer> 
  foreach (var customerGroup in queryCustomersByCity)
  {
      Console.WriteLine(customerGroup.Key);
      foreach (Customer customer in customerGroup)
      {
          Console.WriteLine("    {0}", customer.Name);
      }
  }

var custQuery =
    from cust in customers
    group cust by cust.City into custGroup
    where custGroup.Count() > 2
    orderby custGroup.Key
    select custGroup;

 Join

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var innerJoinQuery =
    from cust in customers
    join dist in distributors on cust.City equals dist.City
    select new { CustomerName = cust.Name, DistributorName = dist.Name };