BUG: `DataFrame.agg([...], numeric_only=True)` returns `NaN` for non-numeric columns instead of excluding them

[gautamvarmadatla]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

import pandas as pd

df = pd.DataFrame({
      "A": [1, 2, 3],
      "B": [1.0, 2.0, 3.0],
      "C": ["foo", "bar", "baz"], })

result = df.agg(["sum", "mean"], numeric_only=True)
print(result)

Issue Description

DataFrame.agg([...], numeric_only=True) returns NaN for non-numeric columns instead of excluding them. This affects DataFrame.agg with a list of string reduction names and numeric_only=True, including reductions such as sum, mean, std, var, sem, median, prod, min, and max, on DataFrames with non-numeric columns such as object, datetime64[ns], timedelta64[ns], StringDtype, CategoricalDtype, and DatetimeTZDtype.

Expected Behavior

Non-numeric columns should be excluded from the result when DataFrame.agg([...], numeric_only=True) is used, rather than being included as all NaN.

Installed Versions

Details

INSTALLED VERSIONS

commit : 2a7587f
python : 3.12.12
python-bits : 64
OS : Windows
OS-release : 11
Version : 10.0.26200
machine : AMD64
processor : Intel64 Family 6 Model 183 Stepping 1, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : English_United States.1252

pandas : 3.1.0.dev0+526.g2a7587fed0.dirty
numpy : 2.4.2
dateutil : 2.9.0.post0
pip : 26.0.1
Cython : 3.2.4
sphinx : None
IPython : 9.10.0
adbc-driver-postgresql: None
adbc-driver-sqlite : None
bs4 : None
bottleneck : 1.6.0
fastparquet : None
fsspec : None
html5lib : None
hypothesis : 6.151.6
gcsfs : None
jinja2 : None
lxml.etree : None
matplotlib : 3.10.8
numba : None
numexpr : 2.14.1
odfpy : None
openpyxl : None
psycopg2 : None
pymysql : None
pyarrow : None
pyiceberg : None
pyreadstat : None
pytest : 9.0.2
python-calamine : None
pytz : 2025.2
pyxlsb : None
s3fs : None
scipy : 1.17.0
sqlalchemy : 2.0.46
tables : None
tabulate : 0.9.0
xarray : None
xlrd : None
xlsxwriter : None
zstandard : None
qtpy : None
pyqt5 : None