Bemærk
Adgang til denne side kræver godkendelse. Du kan prøve at logge på eller ændre mapper.
Adgang til denne side kræver godkendelse. Du kan prøve at ændre mapper.
Switch services using the Version drop-down list. Learn more about navigation.
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer
Detects sequence occurrences based on provided predicates. The plugin is invoked with the evaluate operator.
Syntax
T | evaluate sequence_detect (TimelineColumn, MaxSequenceStepWindow, MaxSequenceSpan, Expr1, Expr2, ..., Dim1, Dim2, ...)
Learn more about syntax conventions.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| T | string |
✔️ | The input tabular expression. |
| TimelineColumn | string |
✔️ | The column reference representing timeline, must be present in the source expression. |
| MaxSequenceStepWindow | timespan |
✔️ | The value of the max allowed timespan between 2 sequential steps in the sequence. |
| MaxSequenceSpan | timespan |
✔️ | The max timespan for the sequence to complete all steps. |
| Expr1, Expr2, ... | string |
✔️ | The boolean predicate expressions defining sequence steps. |
| Dim1, Dim2, ... | string |
✔️ | The dimension expressions that are used to correlate sequences. |
Returns
Returns a single table where each row in the table represents a single sequence occurrence:
- Dim1, Dim2, ...: dimension columns that were used to correlate sequences.
- Expr1TimelineColumn, Expr2TimelineColumn, ...: Columns with time values, representing the timeline of each sequence step.
- Duration: the overall sequence time window
Examples
The following query looks at the table T to search for relevant data from a specified time period.
T | evaluate sequence_detect(datetime_column, 10m, 1h, e1 = (Col1 == 'Val'), e2 = (Col2 == 'Val2'), Dim1, Dim2)
Exploring Storm Events
The following query looks on the table StormEvents (weather statistics for 2007) and shows cases where sequence of 'Excessive Heat' was followed by 'Wildfire' within 5 days.
StormEvents
| evaluate sequence_detect(
StartTime,
5d, // step max-time
5d, // sequence max-time
heat=(EventType == "Excessive Heat"),
wildfire=(EventType == 'Wildfire'),
State
)
Output
| State | heat_StartTime | wildfire_StartTime | Duration |
|---|---|---|---|
| CALIFORNIA | 2007-05-08 00:00:00.0000000 | 2007-05-08 16:02:00.0000000 | 16:02:00 |
| CALIFORNIA | 2007-05-08 00:00:00.0000000 | 2007-05-10 11:30:00.0000000 | 2.11:30:00 |
| CALIFORNIA | 2007-07-04 09:00:00.0000000 | 2007-07-05 23:01:00.0000000 | 1.14:01:00 |
| SOUTH DAKOTA | 2007-07-23 12:00:00.0000000 | 2007-07-27 09:00:00.0000000 | 3.21:00:00 |
| TEXAS | 2007-08-10 08:00:00.0000000 | 2007-08-11 13:56:00.0000000 | 1.05:56:00 |
| CALIFORNIA | 2007-08-31 08:00:00.0000000 | 2007-09-01 11:28:00.0000000 | 1.03:28:00 |
| CALIFORNIA | 2007-08-31 08:00:00.0000000 | 2007-09-02 13:30:00.0000000 | 2.05:30:00 |
| CALIFORNIA | 2007-09-02 12:00:00.0000000 | 2007-09-02 13:30:00.0000000 | 01:30:00 |