How to use the SQL IS NULL Condition

How to use the SQL IS NULL Condition

How to use the SQL IS NULL Condition

Learn how to use the SQL IS NULL Condition to test for a NULL value in SQL. This tutorial explains what a NULL value is and demonstrates how to write a query using the IS NULL Condition with an easy to follow example.

SQL IS NULL Condition (and sample data):
https://www.techonthenet.com/sql/is_n…

SQL Tutorials:
https://www.techonthenet.com/sql/inde…

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Content

0.03 -> The IS NULL condition is used in SQL to test for a NULL value
5.63 -> Before we get started, let's first explain what a NULL value is
10.12 -> NULL is a special value in SQL
12.96 -> While sometimes NULL is confused with an empty string
16.32 -> NULL is actually the absence of a value
19.08 -> NULL are not only found in character or string columns
22.68 -> They can also be found in other datatype columns such as numeric or date
27.32 -> but you can only use a NULL value in a column that allows NULLs
30.98 -> as defined by the CREATE TABLE statement
33.74 -> So to test for a NULL value can be very tricky
36.98 -> You can't simply just say = NULL or != NULL
41.14 -> Instead you need to use a special condition called IS NULL
45.28 -> The IS NULL condition tests an expression and returns TRUE if a NULL value is found
51.04 -> otherwise it returns FALSE
53.086 -> It can be used in the SELECT, INSERT, UPDATE or DELETE statement
57.56 -> Now that you understand what a NULL is
60.22 -> let's cover an example of how to use the IS NULL condition
64.18 -> Here we have a table called customers containing the following data
68.52 -> Notice that there is one record in the table where the favorite_website column is NULL
73.92 -> Let's write a SELECT statement that returns this record
77.4 -> We'll start by entering SELECT * FROM customers
81.14 -> to let the database know that we want to return all columns from the customers table
86.16 -> The WHERE clause is next
88.36 -> This is where we will enter our IS NULL condition
91.76 -> Since we want to return only those records where the favorite_website is NULL
96.46 -> we will enter the following
102.8 -> Now let's run our SELECT statement and see what results we get
106.48 -> As you can see, our SELECT query returns only the one record
110.12 -> where there is a NULL value in the favorite_website column
113.84 -> This covers a simple example of how to use the SQL IS NULL condition
118.42 -> If you would like to see more examples
121.1 -> or would like to download the sample data we used for this tutorial
124.44 -> please visit our website at TechOnTheNet.com
127.34 -> You can also try the examples in our SQL editor on our website
131.6 -> Look for the "TRY IT" button next to each example
134.95 -> If you found our tutorial helpful, please leave a like on this video
139.02 -> and don't forget to subscribe to our YouTube channel for more great SQL tutorials

Source: https://www.youtube.com/watch?v=DUGppOtEX-s