Interface C#

Interface 

    interface IBankCustomer

    {

        void DepositMoney();

        void WithdrawMoney();

    }

    public class Demo : IBankCustomer

    {

        public void DepositMoney()

        {

            Console.WriteLine("Deposit Money");

        }

        public void WithdrawMoney()

        {

            Console.WriteLine("Withdraw Money");

        }

        public static void Main()

        {

            Demo DemoObject = new Demo();

            DemoObject.DepositMoney();

            DemoObject.WithdrawMoney();

        }

    }

• Interface No need access modifiers, default is public.
• Interface methods only header, no body.
• Interface No Field.
• Interface No Constructor.
• Interface can inherit other interface.
• Child Class must implement all the Interface method.
• Child Class can inherit mutiple Interface.

Different Interface and abstract Class

1.A class cannot inherit more than one class (class DerivedClass : BaseClass1, BaseClass2),

interface can (public class Demo : Interface1, Interface2)

2. Abstract class can have abstract or non abstract method;

EXEC Query

DECLARE @EndDate VARCHAR(10);

DECLARE @SQL VARCHAR(5000);

DECLARE @LastDate VARCHAR(10);

DECLARE @StartDate VARCHAR(10);

DECLARE @StartYear VARCHAR(4);

DECLARE @StartMonth VARCHAR(2);

SET @StartDate = CONVERT(VARCHAR(20),DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE()) -1, 0),23);

SET @EndDate = CONVERT(VARCHAR(20),DATEADD(MONTH,1,@StartDate),23);

SET @LastDate = CONVERT(VARCHAR(20),DATEADD(Day,-1,@EndDate),23);

SET @StartYear = CONVERT(VARCHAR(4),datepart(yyyy,@StartDate));

SET @StartMonth = CONVERT(VARCHAR(2),datepart(mm,@StartDate));

Set @SQL = 'Select *,date as ''Trans Date'' From DBYear'+ @StartYear  +'.dbo.Table WHERE TransDate BETWEEN '''+ @StartDate + ''' AND '''+ @EndDate + '''; 

exec(@SQL)

select(@SQL)