We can use SQL ISNULL to replace existing NULL values with a specific value. For example, we want to return Employee salary 10,000 if it is NULL in the Employee table. … We do not have any NULL value in the table now; therefore if we run the query with SQL Server ISNULL, it returns actual values of the rows.

Why do we use Isnull?

The ISNULL() function is used to check if a value is null and if it is will return the replacement value specified when calling the function.

What is the difference between Isnull and Ifnull?

The MySQL ISNULL() function is used to check for any NULL values in the expression passed to it as a parameter. … If the expression does not have or result in NULL, the function returns 0. The MySQL IFNULL() function is used to return a specified value if the expression is NULL.