The quote marks used to quote column names (presumably to support multiword
columns in mysql) cause queries to fail on PostgreSQL.   I know that
PostgreSQL is not supported by this module at this time, but correcting the
quote marks is all I've needed to make it work for simple queries.

Additionally, while investigating this, I also noticed that the the error
message returned a) doesn't include the query generated for the SQL server
(making it hard to determine what quoting you need to do on the client
query side) and b) explicitly says "mysql error" instead of a more generic
and meaningful "database server error"

I've attached a patch that uses the right quote marks for PostgreSQL and
returns a more detailed message when an error occurs.

Unfortunately, I don't know if the same quote marks will work with mysql. 
If they do, I'd be thrilled if you could switch to them, otherwise this
information may be useful as you look at broadening support to other
database servers.