KQL quick reference

This article shows you a list of functions and their descriptions to help get you started using Kusto Query Language.

Operator/Function Description Syntax
Filter/Search/Condition Find relevant data by filtering or searching
where Filters on a specific predicate T | where Predicate
where contains/has Contains: Looks for any substring match
Has: Looks for a specific word (better performance)
T | where col1 contains/has "[search term]"
search Searches all columns in the table for the value [TabularSource |] search [kind=CaseSensitivity] [in (TableSources)] SearchPredicate
take Returns the specified number of records. Use to test a query
Note: _take_ and _limit_ are synonyms.
T | take NumberOfRows
case Adds a condition statement, similar to if/then/elseif in other systems. case(predicate_1, then_1, predicate_2, then_2, predicate_3, then_3, else)
distinct Produces a table with the distinct combination of the provided columns of the input table distinct [ColumnName], [ColumnName]
Date/Time Operations that use date and time functions
ago Returns the time offset relative to the time the query executes. For example, ago(1h) is one hour before the current clock's reading. ago(a_timespan)
format_datetime Returns data in various date formats. format_datetime(datetime , format)
bin Rounds all values in a timeframe and groups them bin(value,roundTo)
Create/Remove Columns Add or remove columns in a table
print Outputs a single row with one or more scalar expressions print [ColumnName =] ScalarExpression [',' ...]
project Selects the columns to include in the order specified T | project ColumnName [= Expression] [, ...]
Or
T | project [ColumnName | (ColumnName[,]) =] Expression [, ...]
project-away Selects the columns to exclude from the output T | project-away ColumnNameOrPattern [, ...]
extend Creates a calculated column and adds it to the result set T | extend [ColumnName | (ColumnName[, ...]) =] Expression [, ...]
Sort and Aggregate Dataset Restructure the data by sorting or grouping them in meaningful ways
sort Sorts the rows of the input table by one or more columns in ascending or descending order T | sort by expression1 [asc|desc], expression2 [asc|desc], …
top Returns the first N rows of the dataset when the dataset is sorted using by T | top numberOfRows by expression [asc|desc] [nulls first|last]
summarize Groups the rows according to the by group columns, and calculates aggregations over each group T | summarize [[Column =] Aggregation [, ...]] [by [Column =] GroupExpression [, ...]]
count Counts records in the input table (for example, T)
This operator is shorthand for summarize count()
T | count
join Merges the rows of two tables to form a new table by matching values of the specified column(s) from each table. Supports a full range of join types: flouter, inner, innerunique, leftanti, leftantisemi, leftouter, leftsemi, rightanti, rightantisemi, rightouter, rightsemi LeftTable | join [JoinParameters] ( RightTable ) on Attributes
union Takes two or more tables and returns all their rows [T1] | union [T2], [T3], …
range Generates a table with an arithmetic series of values range columnName from start to stop step step
Format Data Restructure the data to output in a useful way
lookup Extends the columns of a fact table with values looked-up in a dimension table T1 | lookup [kind = (leftouter|inner)] ( T2 ) on Attributes
mv-expand Turns dynamic arrays into rows (multi-value expansion) T | mv-expand Column
parse Evaluates a string expression and parses its value into one or more calculated columns. Use for structuring unstructured data. T | parse [kind=regex [flags=regex_flags] |simple|relaxed] Expression with * (StringConstant ColumnName [: ColumnType]) *...
make-series Creates series of specified aggregated values along a specified axis T | make-series [MakeSeriesParamters] [Column =] Aggregation [default = DefaultValue] [, ...] on AxisColumn from start to end step step [by [Column =] GroupExpression [, ...]]
let Binds a name to expressions that can refer to its bound value. Values can be lambda expressions to create ad-hoc functions as part of the query. Use let to create expressions over tables whose results look like a new table. let Name = ScalarExpression | TabularExpression | FunctionDefinitionExpression
General Miscellaneous operations and function
invoke Runs the function on the table that it receives as input. T | invoke function([param1, param2])
evaluate pluginName Evaluates query language extensions (plugins) [T |] evaluate [ evaluateParameters ] PluginName ( [PluginArg1 [, PluginArg2]... )
Visualization Operations that display the data in a graphical format
render Renders results as a graphical output T | render Visualization [with (PropertyName = PropertyValue [, ...] )]