Code has been added to clipboard!

SQL NULL Value Explained: How to Use IS NULL & IS NOT NULL

Reading time 1 min
Published Aug 9, 2017
Updated Oct 11, 2019

SQL NULL Values: Main Tips

  • This value defines lost data.
  • Tables already contain NULL values.
  • NULL is handled not like other values.

SQL Working with NULL Values

Below there is a table called "People":

ID Last_Name First_Name Address City
1 Bob Bola Nesdan
2 Bill Bove Ergan 13 Nesdan
3 Benny Bari Nesdanger

Hypothetically the "Adress" column is optional. Then when you write a data record without a value assigned it will receive NULL.

Testing is unavailable using default operators, that's why we use IS NULL/IS NOT NULL.

Udacity
Pros
  • Simplistic design (no unnecessary information)
  • High-quality courses (even the free ones)
  • Variety of features
Main Features
  • Nanodegree programs
  • Suitable for enterprises
  • Paid certificates of completion
Coursera
Pros
  • Professional service
  • Flexible timetables
  • A variety of features to choose from
Main Features
  • Professional certificates of completion
  • University-level courses
  • Multiple Online degree programs
Datacamp
Pros
  • Great user experience
  • Offers quality content
  • Very transparent with their pricing
Main Features
  • Free certificates of completion
  • Focused on data science skills
  • Flexible learning timetable

IS NULL: Example

To select NULL data records we use IS NULL operator:

Example
SELECT col_names
FROM tbl_name
WHERE col_name IS NULL;
Example
SELECT Name, Unit 
FROM Products 
WHERE Unit_On_Order IS NULL;

IS NOT NULL: Example

To select data records with no NULL values we use IS NOT NULL operator:

Example
SELECT col_names
FROM tbl_name
WHERE col_name IS NOT NULL;
Example
SELECT Name, Price 
FROM Products 
WHERE Unit_On_Order IS NOT NULL;

Latest Udacity Coupon Found:

Verified STAFF PICK

75% OFF COURSES

Udacity Black Friday Offer

The best time to save on Udacity courses is now - follow this coupon to access a 75% Udacity Black Friday discount & enjoy learning at a very low cost!

Expiration date: 08/03/2021
3176 People Used
Only 97 Left
Rating
5.0