Identifying NULL/missing values
Let’s consider an example table called customers
to demonstrate how to identify and count NULL or missing values using the COUNT()
function in SQL.
Here’s an example table called customers
:
customer_id |
|
1 |
|
2 |
NULL |
3 |
|
4 |
NULL |
5 |
|
6 |
NULL |
Figure 5.1 – customers table
To identify and count the occurrences of NULL or missing values in the email
column of the customers
table, you can use the following SQL query:
SELECT COUNT(*) AS NULL_count FROM customers...
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