ISNULL function in SQL

ISNULL function in SQL return default value if there is NULL value in the first expression.

Syntax:-

ISNULL (EXPRESSION,'DEFAULT_VALUE');

EXAMPLE:-

SELECT * FROM EMPLOYEE;


SELECT * fROM EMPLOYEE;

     EMPNO EMPNAME                  SALARY     DEPTNO
---------- -------------------- ---------- ----------
         1 CHANCHAL                   1000         10
         2 WANKHADE                   2000         20
         3 SCOTT                      3000        200
         4 TIGER                      4000        200
         5 JOHN                       5000        300
         6 JAKE                       6000        300
         7 null      null       null

SELECT EMPNO,ISNULL(EMPNAME,'SCOTT') AS EMPNAME,ISNULL(SALARY,10000) SALARY
FROM EMPLOYEE
WHERE EMPNO=7;


     EMPNO EMPNAME                  SALARY
---------- -------------------- ----------
         7 SCOTT                     10000


SELECT ISNULL(NULL,'CHANCHAL WANKHADE');

--> CHANCHAL WANKHADE

SELECT ISNULL('CHANCHAL','WANKHADE');

--> CHANCHAL

We can use it to handle the date as well.

SELECT ISNULL(NULL, '2010-01-01');

--> '2010-01-01'




Read Also:- NVL function in Oracle