Function row_number

src/expr/src/relation/func.rs:444–461

The expected input is in the format of `[((OriginalRow, [EncodedArgs]), OrderByExprs...)]` The output is in the format of `[result_value, original_row]`. See an example at `lag_lead`, where the input-output formats are similar.

(
    datums: I,
    callers_temp_storage: &'a RowArena,
    order_by: &[ColumnOrder],
)

/// The output is in the format of `[result_value, original_row]`.
/// See an example at `lag_lead`, where the input-output formats are similar.
fn row_number<'a, I>(
    datums: I,
    callers_temp_storage: &'a RowArena,
    order_by: &[ColumnOrder],
) -> Datum<'a>
where
    I: IntoIterator<Item = Datum<'a>>,
{
    // We want to use our own temp_storage here, to avoid flooding `callers_temp_storage` with a
    // large number of new datums. This is because we don't want to make an assumption about
    // whether the caller creates a new temp_storage between window partitions.
    let temp_storage = RowArena::new();
    let datums = row_number_no_list(datums, &temp_storage, order_by);

    callers_temp_storage.make_datum(|packer| {
        packer.push_list(datums);
    })
}

/// Like `row_number`, but doesn't perform the final wrapping in a list, returning an Iterator
/// instead.