Calculated field
SIGN([amount])
Sample data
| id | amount | units | score | other |
|---|---|---|---|---|
| 1 | -2.5 | 2 | -0.8 | 3 |
| 2 | 0 | 0 | 0 | 4 |
| 3 | 1.5 | 3 | 0.25 | 2 |
| 4 | 4 | 4 | 0.5 | 8 |
| 5 | 9 | 5 | 0.8 | 11 |
| 6 | 16 | 6 | 1 | 14 |
| 7 | null | 7 | null | 9 |
| 8 | 4 | 8 | -0.5 | null |
The same calculation as SQL
SELECT sign(amount) AS result FROM input ORDER BY id
Runs the example above.
SELECT sign(amount) AS result FROM input ORDER BY id
Written for this dialect; not run here.
SELECT sign(amount) AS result FROM input ORDER BY id
Written for this dialect; not run here.
Result
| id | amount | units | score | result |
|---|---|---|---|---|
| 1 | -2.5 | 2 | -0.8 | -1 |
| 2 | 0 | 0 | 0 | 0 |
| 3 | 1.5 | 3 | 0.25 | 1 |
| 4 | 4 | 4 | 0.5 | 1 |
| 5 | 9 | 5 | 0.8 | 1 |
| 6 | 16 | 6 | 1 | 1 |
| 7 | null | 7 | null | null |
| 8 | 4 | 8 | -0.5 | 1 |
Same rows from the calculation and from the SQL in DuckDB.
Where a naive translation goes wrong
- Replacing null results with zero changes missing-value semantics.
Naive SQL
SELECT coalesce((sign(amount)),0) AS result FROM input ORDER BY id
id amount units score result 1 -2.5 2 -0.8 -1 2 0 0 0 0 3 1.5 3 0.25 1 4 4 4 0.5 1 5 9 5 0.8 1 6 16 6 1 1 7 null 7 null 0 8 4 8 -0.5 1 Matches the calculation
SELECT sign(amount) AS result FROM input ORDER BY id
id amount units score result 1 -2.5 2 -0.8 -1 2 0 0 0 0 3 1.5 3 0.25 1 4 4 4 0.5 1 5 9 5 0.8 1 6 16 6 1 1 7 null 7 null null 8 4 8 -0.5 1
Signature
SIGN(number)