startswith operator
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel
Filters a record set for data with a case-insensitive string starting sequence.
The following table compares the startswith operators using the abbreviations provided:
- RHS = right-hand side of the expression
- LHS = left-hand side of the expression
| Operator | Description | Case-Sensitive | Example (yields true) |
|---|---|---|---|
startswith |
RHS is an initial subsequence of LHS | No | "Fabrikam" startswith "fab" |
!startswith |
RHS isn't an initial subsequence of LHS | No | "Fabrikam" !startswith "kam" |
startswith_cs |
RHS is an initial subsequence of LHS | Yes | "Fabrikam" startswith_cs "Fab" |
!startswith_cs |
RHS isn't an initial subsequence of LHS | Yes | "Fabrikam" !startswith_cs "fab" |
For more information about other operators and to determine which operator is most appropriate for your query, see datatype string operators.
Performance tips
Note
Performance depends on the type of search and the structure of the data. For best practices, see Query best practices.
When possible, use the case-sensitive startswith_cs.
Syntax
T | where col startswith (expression)
Learn more about syntax conventions.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| T | string |
✔️ | The tabular input to filter. |
| col | string |
✔️ | The column used to filter. |
| expression | string |
✔️ | The expression by which to filter. |
Returns
Rows in T for which the predicate is true.
Example
StormEvents
| summarize event_count=count() by State
| where State startswith "Lo"
| where event_count > 10
| project State, event_count
Output
| State | event_count |
|---|---|
| LOUISIANA | 463 |