Quantifying completeness
The records for parking violations stored in the parking_violation
table contain missing values for the vehicle_body_type
column. Assume this data is missing completely at random (MCAR) due to human error. In an effort to make the data more complete, you have been tasked with filling in these values. You decide to quantify how many records are missing and perform an analysis for an appropriate fill-in value to replace the missing values.
How many parking_violation
records have a NULL
value for vehicle_body_type
? Write and execute a SELECT
query that computes this number.
Cet exercice fait partie du cours
Cleaning Data in PostgreSQL Databases
Exercice interactif pratique
Passez de la théorie à la pratique avec l’un de nos exercices interactifs
