BUG: Executing SQL containing non-escaped percent sign fails without parameters

[john-bodley]

• closes BUG: Executing SQL containing non-escaped percent sign fails without parameters #34211
• tests added / passed
• passes black pandas
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

[simonjayhawkins]

Thanks @john-bodley for the PR. can you add a note to doc\source\whatsnew\v1.1.0.rst. Does this also close #11896?

[john-bodley]

@simonjayhawkins I added the node per your request. Also per #34211 (comment) I'm uncertain whether this closes #11896.

[WillAyd]

lgtm

[mroeschke]

I'm uncertain whether this closes #11896

If you're open to it @john-bodley, maybe you could add a unit test for #11896 to see if it passes out CI. Then we could close that issue

[john-bodley]

@mroeschke it seems that this PR doesn't resolve #11896 for PostgreSQL per the following CI error (job) when I added a unit test:

self = <sqlalchemy.dialects.postgresql.psycopg2.PGDialect_psycopg2 object at 0x7f7a36467828>
cursor = <cursor object at 0x7f7a375b4e58; closed: -1>
statement = 'INSERT INTO test_frame1 (index, "%%A") VALUES (%(index)s, %(%A)s)'
parameters = {'%A': 1, 'index': 0}
context = <sqlalchemy.dialects.postgresql.psycopg2.PGExecutionContext_psycopg2 object at 0x7f7a363fc5c0>
    def do_execute(self, cursor, statement, parameters, context=None):
>       cursor.execute(statement, parameters)
E       psycopg2.ProgrammingError: incomplete placeholder: '%(' without ')'

[mroeschke]

Thanks for checking @john-bodley. Your PR looks good otherwise

[WillAyd]

Looks like some test failures - @john-bodley can you take a look?

[WillAyd]

@john-bodley can you fix merge conflict?

[john-bodley]

@WillAyd done.

[WillAyd]

Awesome - thanks for the great PR @john-bodley