Sql is null or empty

Problem:

You want to select rows with the value in a given column.

Example:

Let's see a table named with the following columns: , , , and . Assume the column allows values.

EmployeeID	EmployeeName	Dept	Salary
1	Jack Russel	Manager	5600
2	Jan Kowalski	HR	null
3	John Doe	HR	4500
4	Mark Russel	Sales	9000
5	Jane Doe	Sales	null

Now, let’s retrieve all records where the column contains values.

Solution:

To select rows with in a given column, use a special operator :

SELECT EmployeeID, EmployeeName, Salary FROM Employees WHERE Salary IS NULL;

Here’s the result of the query:

EmployeeID	EmployeeName	Salary
2	Jan Kowalski	null
5	Jane Doe	null

Discussion:

in SQL is used to indicate a missing or unknown value.

is special: it is different from all other values, including zero and an empty text field. To test for values specifically in SQL, you must use a special operator . It is impossible to test for the value using any of the usual comparison (such as or ) operators.

A comparison with using a regular comparison operato

how to check null value in sql using case

how to query blank values in sql