Support for MYSQL_TYPE_NULL

[gregyannett]

What language are you using? Python 3.11

What version are you using? 0.3.2a5

What database are you using? MySQL

What dataframe are you using? Polars/Polars2

Can you describe your feature request? Currently, I am unable to query a table in my database due to the presence of MYSQL_TYPE_NULLS. Added support for this would be amazing.

I get the error: thread '<unnamed>' panicked at 'not implemented: MYSQL_TYPE_NULL', /Users/runner/work/connector-x/connector-x/connectorx/src/sources/mysql/typesystem.rs:119:18

Example query / code

import connectorx as cx
import polars as pl
import pandas as pd

query = "SELECT * FROM table_name"
url = "mysql://{user}:{pw}@{server}:{port}/{db}"
df = cx.read_sql(url, query)
# error also occurs when I run: df = pl.read_database(query, url)

What is the error?

thread '<unnamed>' panicked at 'not implemented: MYSQL_TYPE_NULL', /Users/runner/work/connector-x/connector-x/connectorx/src/sources/mysql/typesystem.rs:119:18
---------------------------------------------------------------------------
PanicException                            Traceback (most recent call last)
Cell In[448], line 1
----> 1 cx.read_sql(url, query, return_type="arrow2")

File ~..../lib/python3.11/site-packages/connectorx/__init__.py:297, in read_sql(conn, query, return_type, protocol, partition_on, partition_range, partition_num, index_col)
    294 except ModuleNotFoundError:
    295     raise ValueError("You need to install pyarrow first")
--> 297 result = _read_sql(
    298     conn,
    299     "arrow2" if return_type in {"arrow2", "polars", "polars2"} else "arrow",
    300     queries=queries,
    301     protocol=protocol,
    302     partition_query=partition_query,
    303 )
    304 df = reconstruct_arrow(result)
    305 if return_type in {"polars", "polars2"}:

PanicException: not implemented: MYSQL_TYPE_NULL