`FromSql` is not implemented for `Vec<f64>`

[0x1997]

Is there a way to get a Vec from an array column?

[dvic]

I think you can decode it as an Value::List: https://docs.rs/duckdb/latest/duckdb/types/enum.Value.html#variant.List

[metasim]

I think you can decode it as an Value::List: https://docs.rs/duckdb/latest/duckdb/types/enum.Value.html#variant.List

Is there a way of doing this without having to iterate over Vec<Value> and convert each element into f64, thereby creating a copy of the vector? We've a situation where the vectors aren't small.

[fotonick]

Extracting a List result calls from_list(), which just iterates over those values and calls .to_owned() on each one, as I think you're trying to avoid doing.

fn from_list(start: usize, end: usize, idx: usize, values: &ArrayRef) -> Value {
    Value::List(
        (start..end)
            .map(|row| Row::value_ref_internal(row, idx, values).to_owned())
            .collect(),
    )
}

[fotonick]

To put it in more general terms, if I understand how this all works, every result row is a bunch of ValueRefs, which are pointers to memory that duckdb (not duckdb-rs) owns. I would guess that this memory is freed when you finish iterating to the end of a chunk, so you'd better make a copy.