Daily Sensor Position Averages

SQL practice question · Medium · Window Functions · Google

measurements has one row per sensor reading (measurement_id, measurement_value, measurement_time) where measurement_time is the reading's day. Within each day, number the readings 1, 2, 3, ... in measurement_id order. For each day, return the average value of the odd-numbered readings and of the even-numbered readings (NULL if a day has no even-numbered reading). Output columns: measurement_time, odd_avg, even_avg (both rounded to 2 decimals). Order by measurement_time ascending.

Table: measurements

Schema of measurements
Column	Type
measurement_id	INTEGER
measurement_value	REAL
measurement_time	DATE

Schema of measurements

Column

Type

measurement_id

INTEGER

measurement_value

REAL

measurement_time

DATE

Sample rows of measurements
measurement_id	measurement_value	measurement_time
1	10	2026-01-01
2	20	2026-01-01
3	30	2026-01-01
4	40	2026-01-01
5	50	2026-01-02
6	60	2026-01-02

Sample rows of measurements

measurement_id

measurement_value

measurement_time

2026-01-01

2026-01-02

Expected output on the sample data
measurement_time	odd_avg	even_avg
2026-01-01	20	30
2026-01-02	50	60

Expected output on the sample data

measurement_time

odd_avg

even_avg

2026-01-01

2026-01-02

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