The derivative can be used to get the difference per time unit. When no optional arguments are used the difference per one unit is returned. For example, in a database with second precision the return value will be the difference per second.
derivative([ts [, ts]])
| Arguments | Description |
|---|---|
| ts (optional) | Time unit; difference per given time unit |
| second ts (optional) | Time window; used to get the difference between the first and last value within the given time window. |
A float value.
# Select the difference per second for values in series-001.
select derivative(1s) from 'series-001'
# Select the difference per second between the first and last value
# within each hour for values in 'series-001'
select derivative(1s, 1h) from 'series-001'