SQL Week-Over-Week Comparison | Dataford Interview Questions

Write a SQL query to compare current-week and previous-week performance by segment using CTEs and window functions.

Assume the current week is January 15 through January 21, 2024, and the previous week is January 8 through January 14, 2024. Use segment_performance as the source table and include only segments with data in both weeks.

Output

One row per comparable segment with segment, current_week_performance, previous_week_performance, absolute_change, percentage_change, and current_rank.
Rank segments by current-week performance in descending order, with ties sharing a rank.
Order by current_rank, then segment alphabetically.

Schema

segment_performance

Column	Type	Description
performance_idPK	INT	Unique performance record identifier
segment	VARCHAR(50)	Business segment associated with the performance record
performance_date	DATE	Date on which performance was recorded
performance_value	NUMERIC(12,2)	Performance amount recorded for the segment and date

Your question is SQL Week-Over-Week Comparison. 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

Write a SQL query to compare current-week and previous-week performance by segment using CTEs and window functions.

Output

One row per comparable segment with segment, current_week_performance, previous_week_performance, absolute_change, percentage_change, and current_rank.
Rank segments by current-week performance in descending order, with ties sharing a rank.
Order by current_rank, then segment alphabetically.

Schema

segment_performance

Column	Type	Description
performance_idPK	INT	Unique performance record identifier
segment	VARCHAR(50)	Business segment associated with the performance record
performance_date	DATE	Date on which performance was recorded
performance_value	NUMERIC(12,2)	Performance amount recorded for the segment and date

Your question is SQL Week-Over-Week Comparison. 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.