Top Updated Map Segments Query | Dataford Interview Questions

HERE Technologies monitors map quality by tracking changes made to segments in the HERE map database. Write a PostgreSQL query to identify the five most frequently updated map segments in the Central Europe region during the 30-day period ending February 15, 2025.

Requirements

Count updates for each map segment using only updates from January 16, 2025 through February 15, 2025, inclusive.
Restrict results to the Central Europe region.
Return the five segments with the highest update counts, including ties in the ordering by segment_id ascending.

Schema

map_segments

Column	Type	Description
segment_idPK	INT	Unique map segment identifier
segment_name	VARCHAR(100)	Human-readable segment name
region_name	VARCHAR(50)	HERE map region containing the segment
is_active	BOOLEAN	Whether the segment is currently active

segment_updates

Column	Type	Description
update_idPK	INT	Unique update event identifier
segment_id	INT	Updated map segment
updated_at	TIMESTAMP	Timestamp when the update was recorded
update_type	VARCHAR(30)	Type of map change
updated_by	VARCHAR(80)	Source or analyst responsible for the update

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