Calculated field
WINDOW_MEDIAN(SUM([Revenue]))
Compute using: addressing Period; partitioning Region
Sample data
| Region | Period | Revenue | Cost |
|---|---|---|---|
| Harbor | 1 | 120 | 70 |
| Harbor | 2 | 180 | 100 |
| Harbor | 3 | 180 | 120 |
| Harbor | 4 | 240 | 140 |
| Upland | 1 | 90 | 50 |
| Upland | 2 | 150 | 110 |
| Upland | 3 | null | 90 |
| Upland | 4 | 330 | 190 |
The same calculation as SQL
SELECT CAST((median("Revenue") OVER (PARTITION BY "Region" ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)) AS DOUBLE) AS result FROM input ORDER BY "Region", "Period"Runs the example above.
SELECT CAST((MEDIAN("Revenue") OVER (PARTITION BY "Region")) AS DOUBLE) AS result FROM input ORDER BY "Region", "Period"Written for this dialect; not run here.
SELECT CAST((PERCENTILE_CONT(`Revenue`, 0.5) OVER (PARTITION BY `Region`)) AS FLOAT64) AS result FROM input ORDER BY `Region`, `Period`
Written for this dialect; not run here.
Result
| Region | Period | Revenue | Cost | result |
|---|---|---|---|---|
| Harbor | 1 | 120 | 70 | 180 |
| Harbor | 2 | 180 | 100 | 180 |
| Harbor | 3 | 180 | 120 | 180 |
| Harbor | 4 | 240 | 140 | 180 |
| Upland | 1 | 90 | 50 | 150 |
| Upland | 2 | 150 | 110 | 150 |
| Upland | 3 | null | 90 | 150 |
| Upland | 4 | 330 | 190 | 150 |
Same rows from the calculation and from the SQL in DuckDB.
Where a naive translation goes wrong
- Omitting the region partition allows a calculation to consume marks from other regions.
Naive SQL
SELECT CAST((median("Revenue") OVER ( ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)) AS DOUBLE) AS result FROM input ORDER BY "Region", "Period"Region Period Revenue Cost result Harbor 1 120 70 180 Harbor 2 180 100 180 Harbor 3 180 120 180 Harbor 4 240 140 180 Upland 1 90 50 180 Upland 2 150 110 180 Upland 3 null 90 180 Upland 4 330 190 180 Matches the calculation
SELECT CAST((median("Revenue") OVER (PARTITION BY "Region" ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)) AS DOUBLE) AS result FROM input ORDER BY "Region", "Period"Region Period Revenue Cost result Harbor 1 120 70 180 Harbor 2 180 100 180 Harbor 3 180 120 180 Harbor 4 240 140 180 Upland 1 90 50 150 Upland 2 150 110 150 Upland 3 null 90 150 Upland 4 330 190 150
Signature
WINDOW_MEDIAN(expression, [start, end])