Create a Function in Sql Server

In this article we are going to see how to create a function in sql server, Two types of functions in sql server 
1. system defined 
2. user defined

In user defined based on the return type it is classified, scalar , table valued 

/* Scalar value function RETURN TYPE IS INT */

CREATE FUNCTION CALSUM(@A INT,@B INT)

RETURNS INT

AS

BEGIN

      RETURN @A + @B;

END

SELECT DBO.CALSUM(2,3)

Output :

5

/* Function return varchar */

CREATE FUNCTION EMPID(@ID INT)

RETURNS VARCHAR(4)

AS

BEGIN

   RETURN 'E'+CAST(ISNULL(@ID,0) AS VARCHAR(3))

END

SELECT DBO.EMPID(3)

Output :

E3

/* Table value function */

 CREATE FUNCTION CALTAB(@START INT,@END INT)

 RETURNS @TAB TABLE(NO INT)

 AS

 BEGIN

      WHILE @START <= @END

      BEGIN

      

       INSERT INTO @TAB(NO) SELECT @START

       SELECT @START = @START + 1

     

      END

   RETURN

 END

 SELECT * FROM dbo.caltab(1,10)

Output :

1

2

3

4

5

6

7

8

9

10

From this article you can learn how to create a function in sql server.