Select Group By on Big Data | Dataford Interview Questions

Implement select group by in a big dataset.

Write a SQL query that returns one row per grouping key with the required aggregate metrics. The dataset is large, so the result should be correct and stable for duplicate, missing, and out-of-order rows.

Output

One row per grouping key
Include the grouping key and the aggregated metric columns
Exclude rows that do not meet the required filter conditions
Sort the final result by the grouping key ascending

Schema

big_dataset

Column	Type	Description
record_idPK	BIGINT	Unique row identifier
grouping_key	VARCHAR(50)	Key used to group rows
metric_value	NUMERIC(12,2)	Numeric value to aggregate
is_active	BOOLEAN	Whether the row should be included
created_at	DATE	Row creation date

Your question is Select Group By on Big Data. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Implement select group by in a big dataset.

Output

One row per grouping key
Include the grouping key and the aggregated metric columns
Exclude rows that do not meet the required filter conditions
Sort the final result by the grouping key ascending

Schema

big_dataset

Column	Type	Description
record_idPK	BIGINT	Unique row identifier
grouping_key	VARCHAR(50)	Key used to group rows
metric_value	NUMERIC(12,2)	Numeric value to aggregate
is_active	BOOLEAN	Whether the row should be included
created_at	DATE	Row creation date

Your question is Select Group By on Big Data. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.