Simple Trick Using ISNULL

Simple Trick Using ISNULL:

Step-1: Create Sample Student Table.

CREATE TABLE Student

(

Id INT IDENTITY(1,1) PRIMARY KEY,

StudentName VARCHAR(100) NOT NULL,

LivingLocation VARCHAR(100) NULL

)

Step-2 :Insert Some Sample Data

INSERT INTO Student

SELECT 'Rakesh','Hyderabad'

UNION ALL

SELECT 'Raju','Delhi'

UNION ALL

SELECT 'Madhu','Hyderabad'

UNION ALL

SELECT 'Naresh',NULL

UNION ALL

SELECT 'Venaktesh','Chennai'

Step-3 :Select Data from Student Table

SELECT * FROM Student

If we observe above data of student table we have student id 4 record LivingLocation is NULL.

Step -4 :Select Data from Student Table With Where Clause.

SELECT * FROM Student WHERE LivingLocation='Hyderabad'

In the above query we are included the where clause with LivingLocation is 'Hyderabad'

SELECT * FROM Student WHERE LivingLocation<>'Hyderabad'

In the above query we want data from Student Table whose LivingLocation is not equal to the 'Hyderabad' , but it is not selected the data whose id is '4' ,because of the id of '4' LivingLocation is NULL , but we need that record also in this situation we can we ISNULL function.

SELECT * FROM Student WHERE ISNULL(LivingLocation,'')<>'Hyderabad'