fix(dbapi): avoid running % format when no query parameters are passed #346
Description
Is your feature request related to a problem? Please describe.
It is unexpected to get format errors when a string contains %, but there are no query parameters in the query.
googleapis/python-bigquery-sqlalchemy#72
Describe the solution you'd like
In addition to checking if parameters is none, check if len(parameters) == 0 to avoid unnecessary format operations.