"horizontal sum" in DuckDB?

Question

In Polars I can do:

import polars as pl
df = pl.DataFrame({'a': [1,2,3], 'b': [4, 5, 6]})
df.select(pl.sum_horizontal('a', 'b'))

shape: (3, 1)
┌─────┐
│ a   │
│ --- │
│ i64 │
╞═════╡
│ 5   │
│ 7   │
│ 9   │
└─────┘

Is there a way to do this with DuckDB?

Answer 1

COLUMNS() can now be unpacked as of DuckDB 1.1.0

This does allow you to use the list_* functions e.g.

duckdb.sql("""
from df 
select list_sum(list_value(*columns(*)))
""")

┌──────────────────────────────────┐
│ list_sum(list_value(df.a, df.b)) │
│              int128              │
├──────────────────────────────────┤
│                                5 │
│                                7 │
│                                9 │
└──────────────────────────────────┘