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bool

The bool data type can have one of two states: true or false, as well as the null value.

Alias: boolean.

bool Definition
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A value is considered true in any of the following cases:

  • If it’s the actual bool value true.
  • If it’s one of the following case-insensitive strings: 'true', 't', 'yes', 'y'.
  • If it’s a numeric value equal to 1 (including 1.0).

A value is considered false in any of the following cases:

  • If it’s the actual bool value false.
  • If it’s one of the following case-insensitive strings: 'false', 'f', 'no', 'n'.
  • If it’s a numeric value equal to 0 (including 0.0).

Any values that couldn’t be converted to bool are considered null.

Comparing bool to Numbers
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When comparing bool values to numbers, only 1 is considered true. For example:

ExpressionResult
true == 1true
true == 100false

However, when converting a value to a bool, all non-zero numbers are converted to true:

ExpressionResult
tobool(100)true
bool(-1)true
iff(100, 1, 0)1
not(100)false

bool as a Filter
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To search for any values that are considered true, filter on the literal true value:

  • dataset="foo" something=true
  • dataset="foo" | where something==true

These will match on:

  • Booleans with value true.
  • The following case-insensitive strings: 'true', 't', 'yes', 'y'.
  • Numeric values equal to 1.

To search for any values that are considered false, filter on the literal false value:

  • dataset="foo" something=false
  • dataset="foo" | where something==false

These will match on:

  • Booleans with value false.
  • The following case-insensitive strings: 'false', 'f', 'no', 'n'.
  • Numeric values equal to 0.

Note that searching on "true" or "false” literals with quotes does a string match instead. This means that:

dataset="foo" | where something=="true"

Will match on "true" and true, but not on 1, "yes" or any other bool values.

bool as Function Input
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For any functions that take bool arguments, the values will be automatically converted to true, false or null, according to our bool definition. Mind that all non-zero numbers are converted to true.

For conditional functions, null is treated as false.

ExpressionResult
iif(true, 'true', 'false')'true'
iif('yes', 'true', 'false')'true'
iif(1, 'true', 'false')'true'
iif(123, 'true', 'false')'true'
iif('false', 'true', 'false')'false'
iif(0, 'true', 'false')'false'
iif('abc', 'true', 'false')'false'

bool and the Logical NOT Operator
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Both the logical NOT ! operator and the not function:

  • Return false for all values considered true by the bool definition. Mind that all non-zero numbers are converted to true.
  • Return true for all values considered false by the bool definition.
  • Return null if passed null, or for any values that can’t be converted to true or false.
ExpressionResult
not(true)false
not('true')false
not('yes')false
not(1)false
not(100)false
not(false)true
not('false')true
not('no')true
not(0)true
not(null)null
not("hello")null