Struct AggregateExecutor 

pub struct AggregateExecutor;

Executes SPARQL 1.1 aggregate operations.

Implementations

impl AggregateExecutor

pub fn group_by( rows: &[HashMap<String, String>], group_vars: &[String], ) -> HashMap<GroupKey, Vec<HashMap<String, String>>>

Partition rows into groups based on the values of group_vars.

Rows that do not bind a group variable get an empty string for that variable. If group_vars is empty, all rows form a single group with an empty key.

pub fn apply( func: &AggregateFunc, var: &str, group: &[HashMap<String, String>], ) -> AggregateValue

Apply an aggregate function over a single group.

var is the name of the variable being aggregated.

pub fn execute( rows: &[HashMap<String, String>], group_vars: &[String], aggregates: &[(String, AggregateFunc, String)], ) -> Vec<AggregateResult>

Execute aggregate functions over all groups, returning sorted results.

aggregates is a list of (input_var, func, output_var) triples.

pub fn having_filter( results: &[AggregateResult], var: &str, op: &str, value: &str, ) -> Vec<AggregateResult>

Filter aggregate results using a HAVING-like condition.

Compares the AggregateValue bound to var against value using op. Supported operators: "=", "!=", "<", ">", "<=", ">=".