Function aggregate_batch 

pub fn aggregate_batch(
    batch: &RecordBatch,
    functions: &[AggFn],
    field_columns: &[&str],
    memory_tracker: Option<&MemoryTracker>,
) -> Result<RecordBatch>

Apply aggregation to a RecordBatch without grouping.

Returns a single-row RecordBatch with one column per field per function.

Errors

Returns an error if the batch is empty or columns have unexpected types.