Removing missing values
It is common to find missing values in your data. SQL Server represents missing values with NULL
.
IS NULL
and IS NOT NULL
enable you to select or remove the rows where missing values are represented by NULL
.
The airport_city
column of the airports
table has some NULL
values. Try to find them!
Cet exercice fait partie du cours
Cleaning Data in SQL Server Databases
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
SELECT *
-- Select the appropriate table
FROM ___
-- Exclude the rows where airport_city is NULL
WHERE ___ ___ ___ ___