Filling missing values using ISNULL()
In the previous exercise, you practiced how to exclude and select the rows with NULL values. However, depending on the business assumptions behind your data, you may want to select all the rows with NULL values, but replacing these NULL values with another value. You can do it using ISNULL().
Now, you want to replace all the NULL values for the airport_city and airport_state columns with the word 'Unknown', using ISNULL().
Diese Übung ist Teil des Kurses
Cleaning Data in SQL Server Databases
Anleitung zur Übung
- Replace the missing values for
airport_citycolumn with the'Unknown'string. - Replace the missing values for
airport_statecolumn with the'Unknown'string.
Interaktive Übung
Vervollständige den Beispielcode, um diese Übung erfolgreich abzuschließen.
SELECT
airport_code,
airport_name,
-- Replace missing values for airport_city with 'Unknown'
___(___, '___') AS airport_city,
-- Replace missing values for airport_state with 'Unknown'
___(___, '___') AS airport_state
FROM airports