title: Sqlalchemy mysql FLOAT precision and length
body: <p>I'm trying to model an existing database with SQLAlchemy and I am very close.</p>
  
  <p>My sticking point is the FLOAT types.</p>
  
  <p>In the MySQL database they are <code>Float(10,2)</code></p>
  
  <p>Using SQLAlchemy, I'm unable to replicate this regardless of how I try to create them.</p>
  
  <p>Examples are:</p>
  
  <pre class="lang-py prettyprint-override"><code>from sqlalchemy.dialects.mysql import FLOAT
  from sqlalchemy.ext.declarative import declarative_base
  
  connection_string = 'xxxxx'
  
  engine = create_engine(connection_string, echo=True, encoding='utf-8')
  Base = declarative_base(engine)
  
  class TestTable(Base):
      __tablename__ = 'my_test_table'
      float_1 = Column(FLOAT(length=10, precision=2))
      float_2 = Column(Float(10,2))
      float_3 = Column(Float(as_decimal=True))
  </code></pre>