Count the number of data per time series
You are a data scientist on a team evaluating weather time series data that another team has uploaded from an import file and you have been called upon to analyze the usefulness of this new dataset.
You have two tables that contain the data. Each time series is identified by a filename, station_id, and two character state code. You have been told that two of the stations have fewer data points than the other stations.
Write a query that indicates which two stations have the fewest data, sorted in ascending number of data points.
The tables temperature_stations and temperatures_monthly are available to you.
Cet exercice fait partie du cours
Time Series Analysis in PostgreSQL
Instructions
- Join the two tables and count the number of data per station, sorted in ascending order.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
-- Count the number of data per station, sorted in ascending order
SELECT filename, state, ___ AS count
FROM temperatures_monthly
JOIN ___ USING(___)
GROUP BY filename, state
___;