Microsoft Azure Data FundamentalsDescribe core data conceptsEasy
A data scientist is working with a dataset that contains information about customer purchases. Each record includes 'CustomerID', 'ProductID', 'Quantity', and 'OrderDate'. To analyze the total quantity of products sold per customer over time, the data scientist needs to group the data by 'CustomerID' and 'OrderDate' and then sum 'Quantity'. This operation is an example of which data processing concept?
- AFiltering
- BJoining
- CSorting
- DAggregation
Show answer & explanationAnswer & explanation
Correct answer: D. Aggregation
Aggregation involves combining multiple data points into a single summary value. In this scenario, summing the 'Quantity' after grouping by 'CustomerID' and 'OrderDate' is a classic aggregation operation.
Why the other options are wrong
- A. Filtering selects a subset of data based on criteria, not combining values.
- B. Joining combines data from multiple sources, not summarizing within a single dataset.
- C. Sorting arranges data in a specific order, not summarizing it.
Aggregation
Aggregation is a data processing operation that combines multiple data points into a single summary value by applying functions like SUM, AVG, COUNT, MIN, or MAX.
- Summarizes data.
- Often used with grouping (e.g., GROUP BY).
- Common in analytical queries and reporting.
Memory trick: Aggregations 'gather' and 'sum' up the data.