the dataframe of "sql(query).fetch_df()" lost index

[jacktang]

What happens?

I load one dateframe (parquet file) with multi-index from s3 by the code:

sql = "SELECT * FROM read_parquet('s3://the-path-of-parquet');"
df = con.sql(sql).fetchdf() # <- the dataframe lost the index

To Reproduce

sql = "SELECT * FROM read_parquet('s3://the-path-of-parquet');"
df = con.sql(sql).fetchdf() # <- the dataframe lost the index

OS:

OSX

DuckDB Package Version:

1.3.2

Python Version:

3.11.0

Full Name:

Jack Tang

Affiliation:

Acme

What is the latest build you tested with? If possible, we recommend testing with the latest nightly build.

I have not tested with any build

Did you include all relevant data sets for reproducing the issue?

No - Other reason (please specify in the issue body)

Did you include all code required to reproduce the issue?

• Yes, I have

Did you include all relevant configuration to reproduce the issue?

• Yes, I have

[paultiq]

Maybe same or related to duckdb/duckdb#1011

This is what I see with a multindex (Pandas 2.3.3, DuckDB 1.4.1):

import duckdb, pandas as pd
df = pd.DataFrame({"v":[0]}, index=pd.MultiIndex.from_tuples([("A",1)], names=["k1","k2"]))

display(df)
df.to_parquet("mi.parquet"); 

df2 = duckdb.sql("SELECT * FROM read_parquet('mi.parquet')").fetchdf()
display(df2)

		v
k1	k2
A	1	0

	v	k1	k2
0	0	A	1