Format characters in SQL comments raises error with SQLAlchemy connection

[derek-pyne]

Context: Pandas read_sql is now raising a warning suggesting moving from a DB-API connection to a SQLAlchemy connection. Hence we are trying to make the switch.

Issue: When using a SQLAlchemy connection, if the query has any format characters in it, then an error is raised. No issue with a DB-API connection.

Example query:

-- Format character in a comment %
SELECT 1

Likely Cause When deciding whether to format the operation, PyHive checks if the given parameters is None.

https://github.com/dropbox/PyHive/blob/d199a1bd55c656b5c28d0d62f2d3f2e6c9a82a54/pyhive/presto.py#L256

However, SQLAlchemy (1.4.31) always at least passes an empty dictionary (since it builds these params off of kwargs which default to an empty dict) so it is never None.

https://github.com/sqlalchemy/sqlalchemy/blob/2eac6545ad08db83954dd3afebf4894a0acb0cea/lib/sqlalchemy/engine/base.py#L1196

Likely Fix Just need to also check if params is an empty dict:

if params is None or not params: