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!hasprefix operators

Filters a record set for data that does not include a case-insensitive 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 hasprefix 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 more information about other operators and to determine which operator is most appropriate for your query, see datatype string operators.

Case-insensitive operators are currently supported only for ASCII-text. For non-ASCII comparison, use the tolower() function.

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.

If you're testing for the presence of a symbol or alphanumeric word that is bound by non-alphanumeric characters at the start or end of a field, for faster results use has or in.

Syntax

T | where Column !hasprefix (Expression)

Arguments

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

Returns

Rows in T for which the predicate is true.

Example


events
    | 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 "soft"
    | take 2

Results

original_time data_source_name name
2023-04-11T15:31:24.714Z microsoftWindowsSource1 Database Engine Stopped
2023-04-11T15:31:24.714Z microsoftWindowsSource1 DHCP Scope is Full or Almost Full