Some Linq queries for beginners

Following are some of the basic Linq command/samples for those who just want to start learning Linq. So this will help a lot to all the beginners to easily understand Linq queries.

// Basic Query

// To achieve  Select * From ProductMst  you need to write following linq Query

  var Result1 = from p in db.ProductMst

                 select p;

// To achieve  Select ProductID, ProductName, Price From ProductMst you need to write following linq Query

    var Result2 = from p in db.ProductMst

                 select new {

                     p.ProductID,

                     p.ProductName,

                     p.Price

                 };

// Where Clause Query

// To achieve  Select * From ProductMst Where ProductID = 1 you need to write following linq Query

    var Result3 = from p in db.ProductMst

                 where p.ProductID == 1

                 select p;

// To achieve Select * From ProductMst Where SupplierId =2 and Price > 10 you need to write following linq Query

    var Result4 = from p in db.ProductMst

                 where p.SupplierID == 2 && p.Price > 10

                 select p;

// To achieve Select * From ProductMst Where SupplierId =2 Or SupplierId=5 you need to write following linq Query

    var Result5 = from p in db.ProductMst

                 where p.SupplierID == 2 || p.SupplierID == 5

                 select p;

// Order By Query

//To achieve   Select * From ProductMst Order By ProductId you need to write following linq Query

    var Result6 = from p in db.ProductMst

                 orderby p.ProductID

                 select p;

// To achieve  Select * From ProductMst Order By ProductId Desc you need to write following linq Query

    var Result7 = from p in db.ProductMst

                 orderby p.ProductID descending

                 select p;

// To achieve  Select * From ProductMst Order By CategoryId, Price Desc you need to write following linq Query

    var Result8 = from p in db.ProductMst

                 orderby p.CategoryID, p.Price descending

                 select p;

// Top Query

//To achieve Select Top 5 * From ProductMst you need to write following linq Query

    var Result9 = (from p in db.ProductMst

                 select p).Take(5);

//To achieve Select Top 1 * From ProductMst you need to write following linq Query

    var Result10 = (from p in db.ProductMst

                   select p).Take(1);

     or

    var Result11 = (from p in db.ProductMst

                   select p).First();

// Distinct Query

//To achieve Select Distinct CategoryId From ProductMst you need to write following linq Query

    var Result13 = (from p in db.ProductMst

                   select p.CategoryID).Distinct();

// Group By Query

//To achieve Select CategoryId, Count(CategoryID) As FieldName From ProductMst Group By CategoryId you need to write following linq Query

    var Result14 = from p in db.ProductMst

                  group p by p.CategoryID into g

                  select new {

                      CategoryId = g.Key,

                      FieldName = g.Count()

                  };

//To achieve Select CategoryId, Avg(UnitPrice) As NewField From ProductMst Group By CategoryId you need to write following linq Query

    var Result15 = from p in db.ProductMst

                  group p by p.CategoryID into g

                  select new {

                      CategoryId = g.Key,

                      FieldName = g.Average(S => S.Price)

                  };

// Union Query

//To achieve Select * From ProductMst Where CategoryId =1 union Select *  From ProductMst Where 

CategoryId = 2 you need to write following linq Query

    var Result17 = (from p in db.ProductMst

                   where p.CategoryID == 1

                   select p).Union(

                       from m in db.ProductMst

                       where m.CategoryID == 2

                       select m

                   );

// Inner Join

// To achieve select p.ProductName, c.categoryName from ProductMst p inner join CategoryMst c 

on p.CategoryID=c.Category  you need to write following linq Query

   var Result18=from n in db.ProductMst

                        join c in db.CategoryMst

                        on n.CategoryID equals c.CategoryID

                        select new

                        {

                           n.ProductName, c.categoryName 

                        };