Tabular expression statements

The tabular expression statement is what people usually have in mind when they talk about queries. This statement usually appears last in the statement list, and both its input and its output consists of tables or tabular datasets. Any two statements must be separated by a semicolon.

A tabular expression statement is generally composed of tabular data sources such as tables, tabular data operators such as filters and projections, and optional rendering operators. The composition is represented by the pipe character (|), giving the statement a regular form that visually represents the flow of tabular data from left to right. Each operator accepts a tabular dataset "from the pipe", and other inputs including more tabular datasets from the body of the operator, then emits a tabular dataset to the next operator that follows.


Source | Operator1 | Operator2 | RenderInstruction

Learn more about syntax conventions.


Name Type Required Description
Source string A tabular data source. See Tabular data sources.
Operator string Tabular data operators, such as filters and projections.
RenderInstruction string Rendering operators or instructions.

Tabular data sources

A tabular data source produces sets of records, to be further processed by tabular data operators. The following list shows supported tabular data sources:


Filter rows by condition

The following query counts the number of records in the StormEvents table that have a value of "FLORIDA" in the State column.

| where State == "FLORIDA"
| count



Combine data from two tables

In the following example, the join operator is used to combine records from two tabular data sources: the StormEvents table and the PopulationData table.

| where InjuriesDirect + InjuriesIndirect > 50
| join (PopulationData) on State
| project State, Population, TotalInjuries = InjuriesDirect + InjuriesIndirect


State Population TotalInjuries
ALABAMA 4918690 60
CALIFORNIA 39562900 61
KANSAS 2915270 63
MISSOURI 6153230 422
OKLAHOMA 3973710 200
TENNESSEE 6886720 187
TEXAS 29363100 137