!startswith operator
Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel
Filters a record set for data that doesn't start with a case-insensitive search string.
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 column !startswith (expression)
Learn more about syntax conventions.
Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| T | string |
✔️ | The tabular input whose records are to be filtered. |
| column | string |
✔️ | The column by which to filter. |
| expression | scalar | ✔️ | The scalar or literal expression for which to search. |
Returns
Rows in T for which the predicate is true.
Example
StormEvents
| summarize event_count=count() by State
| where State !startswith "i"
| where event_count > 2000
| project State, event_count
Output
| State | event_count |
|---|---|
| TEXAS | 4701 |
| KANSAS | 3166 |
| MISSOURI | 2016 |