title: Pandas read_sql with parameters
body: <p>Are there any examples of how to pass parameters with an SQL query in Pandas?</p>
  
  <p>In particular I'm using an SQLAlchemy engine to connect to a PostgreSQL database.  So far I've found that the following works:</p>
  
  <pre><code>df = psql.read_sql(('select "Timestamp","Value" from "MyTable" '
                       'where "Timestamp" BETWEEN %s AND %s'),
                     db,params=[datetime(2014,6,24,16,0),datetime(2014,6,24,17,0)],
                     index_col=['Timestamp'])
  </code></pre>
  
  <p>The Pandas documentation says that params can also be passed as a dict, but I can't seem to get this to work having tried for instance:</p>
  
  <pre><code>df = psql.read_sql(('select "Timestamp","Value" from "MyTable" '
                       'where "Timestamp" BETWEEN :dstart AND :dfinish'),
                     db,params={"dstart":datetime(2014,6,24,16,0),"dfinish":datetime(2014,6,24,17,0)},
                     index_col=['Timestamp'])
  </code></pre>
  
  <p>What is the recommended way of running these types of queries from Pandas?</p>