surprising `fetchall` return value on some queries, since 1.5.2

Start by running the provided Python reproductions with DuckDB 1.5.2 and compare their fetchall results with 1.5.1, focusing on CREATE OR REPLACE, PIVOT, and their combination. Done means the combined statement returns the expected result set while the standalone cases continue to pass.

What happens?

duckdb.execute of CREATE OR REPLACE or PIVOT each return a result set with row count, but the same call with both statements together returns an empty result since 1.5.2 of the Python library.

To Reproduce

In 1.5.1 and 1.5.2 this succeeds and the assertions pass:

import duckdb

assert duckdb.execute("create or replace table t1 as select 1").fetchall() == [(1,)]
assert duckdb.execute("""PIVOT (
    SELECT 'X' AS category, 100 AS amount
    UNION ALL
    SELECT 'Y' AS category, 200 AS amount
) ON category USING SUM(amount);""").fetchall() == [(100, 200)]

In 1.5.1 we continue to get a result set with CREATE OR REPLACE and PIVOT so this succeeds:

import duckdb

assert duckdb.execute("""create or replace table t1 as PIVOT (
    SELECT 'X' AS category, 100 AS amount
    UNION ALL
    SELECT 'Y' AS category, 200 AS amount
) ON category USING SUM(amount);""").fetchall() == [(1,)]

In 1.5.2 and above, the query succeeds but the assertion fails:

AssertionError                            Traceback (most recent call last)
Cell In[2], line 1
----> 1 assert duckdb.execute("""create or replace table t1 as PIVOT (
      2     SELECT 'X' AS category, 100 AS amount
      3     UNION ALL
      4     SELECT 'Y' AS category, 200 AS amount
      5 ) ON category USING SUM(amount);""").fetchall() == [(1,)]

AssertionError:

OS:

OSX

DuckDB Package Version:

1.5.2

Python Version:

3.12.13

Full Name:

Shahin Saneinejad

Affiliation:

Axiom Bio

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

I have tested with a stable release

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

Yes

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