countif() (aggregation function)

Returns a count of rows for which Predicate evaluates to true. Can only be used only in context of aggregation inside summarize.

Syntax

countif (Predicate)

Arguments

Predicate: Expression that will be used for aggregation calculation. Predicate can be any scalar expression with return type of bool (evaluating to true/false).

Returns

Returns a count of rows for which Predicate evaluates to true.

Example

let T = datatable(name:string, day_of_birth:long)
[
   "John", 9,
   "Paul", 18,
   "George", 25,
   "Ringo", 7
];
T
| summarize countif(strlen(name) > 4)

See also

count() function, which counts rows without predicate expression.