SqlAlchemy mysql millisecond or microsecond precision

This seems to be an open issue with MySQLdb, not MySQL or SQLAlchemy.

http://sourceforge.net/p/mysql-python/feature-requests/24/

You can try using another MySQL driver library -- check SQLAlchemy documentation for supported options --, or you can try the monkeypatch suggested in the open issue.

The problem I was having is that the stock SqlAlchemy DATETIME class does not work with the mysql requirement of passing a (6) value into the constructor in order to represent fractional time values. Instead, one needs to use the sqlalchemy.dialects.mysql.DATETIME class. This class allows the use of the fsp parameter (fractional seconds parameter.) So, a column declaration should actually look like:

dateCreated = Column(DATETIME(fsp=6)) 

Thanks to those others who replied. It helped guide my investigation to ultimately stumbling over this esoteric and very confusing distinction.