Calculated field
INDEX() / SIZE()
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((row_number() OVER (PARTITION BY "Region" ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)::DOUBLE / count(*) 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((row_number() OVER (PARTITION BY "Region" ORDER BY "Period") / count(*) OVER (PARTITION BY "Region" ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)) AS DOUBLE) AS result FROM input ORDER BY "Region", "Period"
Written for this dialect; not run here.
SELECT CAST((row_number() OVER (PARTITION BY `Region` ORDER BY `Period`) / count(*) OVER (PARTITION BY `Region` ORDER BY `Period` ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)) 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 | 0.25 |
| Harbor | 2 | 180 | 100 | 0.5 |
| Harbor | 3 | 180 | 120 | 0.75 |
| Harbor | 4 | 240 | 140 | 1 |
| Upland | 1 | 90 | 50 | 0.25 |
| Upland | 2 | 150 | 110 | 0.5 |
| Upland | 3 | null | 90 | 0.75 |
| Upland | 4 | 330 | 190 | 1 |
Same rows from the calculation and from the SQL in DuckDB.
Where a naive translation goes wrong
- An unpartitioned SQL window mixes independent regional calculation sequences.
Naive SQL
SELECT CAST((row_number() OVER ( ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)::DOUBLE / count(*) 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 0.125 Harbor 2 180 100 0.375 Harbor 3 180 120 0.625 Harbor 4 240 140 0.875 Upland 1 90 50 0.25 Upland 2 150 110 0.5 Upland 3 null 90 0.75 Upland 4 330 190 1 Matches the calculation
SELECT CAST((row_number() OVER (PARTITION BY "Region" ORDER BY "Period" ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW)::DOUBLE / count(*) 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 0.25 Harbor 2 180 100 0.5 Harbor 3 180 120 0.75 Harbor 4 240 140 1 Upland 1 90 50 0.25 Upland 2 150 110 0.5 Upland 3 null 90 0.75 Upland 4 330 190 1
Signature
INDEX() / SIZE()