/// Returns an iterable collection of data in group columns and aggregate
/// columns, optionally filtered by the provided predicate. Results are
/// merged across all row groups within the returned table.
///
/// Returns an error if the specified table does not exist.
///
/// Note: `read_aggregate` currently only supports grouping on "tag"
/// columns.
Returns an iterable collection of data in group columns and aggregate
columns, optionally filtered by the provided predicate. Results are
merged across all row groups within the returned table.

Returns an error if the specified table does not exist.

`read_aggregate` currently only supports grouping on "tag"
columns.
Returns an iterable collection of data in group columns and aggregate columns optionally filtered by the provided predicate . Results are merged across all row groups within the returned table . Returns an error if the specified table does not exist . ` read_aggregate ` currently only supports grouping on " tag " columns .
pub(crate) fn read_aggregate(
        &self,
        table_name: &str,
        predicate: Predicate,
        group_columns: &Selection<'_>,
        aggregates: &[(ColumnName<'_>, AggregateType)],
    ) -> Result<table::ReadAggregateResults> {
        // read lock on chunk.
        let chunk_data = self.chunk_data.read();
        let table = chunk_data
            .data
            .get(table_name)
            .context(TableNotFound { table_name })?;
        table
            .read_aggregate(predicate, group_columns, aggregates)
            .context(TableError)
    }
pub ( crate ) fn read_aggregate ( & self , table_name : & str , predicate : Predicate , group_columns : & Selection < ' _ > , aggregates : & [ ( ColumnName < ' _ > , AggregateType ) ] , ) -> Result < table :: ReadAggregateResults > { // read lock on chunk. let chunk_data = self . chunk_data . read ( ) ; let table = chunk_data . data . get ( table_name ) . context ( TableNotFound { table_name } ) ? ; table . read_aggregate ( predicate , group_columns , aggregates ) . context ( TableError ) }
Returns an iterable collection of data in group columns and aggregate
columns, optionally filtered by the provided predicate.
Returns an iterable collection of data in group columns and aggregate columns optionally filtered by the provided predicate .
&self
table_name
&str
predicate
Predicate
group_columns
&Selection<'_>
aggregates
&[(ColumnName<'_>, AggregateType)]