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hasprefix_cs operator

Filters a record set for data with a case-sensitive starting string. has searches for indexed terms, where a term is three or more characters. If your term is fewer than three characters, the query scans the values in the column, which is slower than looking up the term in the term index.

The following table provides a comparison of the has operators:

Operator Description Case-Sensitive Example (yields true)
hasprefix RHS is a term prefix in LHS No "microsoftWindowsSource1" hasprefix "MICRO"
!hasprefix RHS isn't a term prefix in LHS No "microsoftWindowsSource1" !hasprefix "soft"
hasprefix_cs RHS is a term prefix in LHS Yes "microsoftWindowsSource1" hasprefix_cs "micro"
!hasprefix_cs RHS isn't a term prefix in LHS Yes "microsoftWindowsSource1" !hasprefix_cs "MICRO"

The following abbreviations are used in the table above:

  • RHS = right hand side of the expression
  • LHS = left hand side of the expression

For further information about other operators and to determine which operator is most appropriate for your query, see datatype string operators.

Performance tips

Performance depends on the type of search and the structure of the data.

For faster results, use the case-sensitive version of an operator, for example, hasprefix_cs, not hasprefix.


T | where col hasprefix_cs (expression)


  • T - The tabular input whose records are to be filtered.
  • col - The column to filter.
  • expression - Scalar or literal expression.


Rows in T for which the predicate is true.


// hassuffix case sensitive
    | project original_time, data_source_name, name
    //--- Search for the last 5 mins of data    
    | where original_time > now(-5m)
    //--- USER Criteria Here
    | where data_source_name hasprefix_cs "micro"
    | take 2


original_time data_source_name name
2023-04-11T15:59:37.596Z microsoftWindowsSource2 Instance ID Information
2023-04-11T15:49:14.117Z microsoftWindowsSource2 A user account was deleted