title: Pyodbc returning query results intermittently
body: <p>I am completely stumped as I the code can connect to the database and returns the required results.  However, running this multiple times does not give the same results.  I either get all the records expected back or there are no records that come back. I do not make any changes which is why I do not understand what is making the issue intermittent.</p>
  
  <p>Here is the code</p>
  
  <pre><code>import pandas as pd
  import sys
  import pyodbc
  import numpy as np
  pyodbc.pooling = False
  
  cnxn = pyodbc.connect('DRIVER={SQL Server};SERVER="SERVER\\LOCATION",PORTNUM;DATABASE=DBNAME;UID=USERNAME;
  PWD=PASSWORD;chunksize =100')
  cursor = cnxn.cursor()
  
  sql="SELECT ida,idb,name  from schema.dbo.table  where ida=? and idb=? and date_x between '1-jan-12' and '31-dec-12' order by date_x"
  
  df1 = pd.read_sql(sql, cnxn,params={'ida','idb'})
  
  sql="SELECT ida,idb,name  from schema.dbo.table  where ida=? and idb=? and date_x between '1-jan-12' and '31-dec-12' order by date_x"
  
  df2 = pd.read_sql(sql, cnxn,params={'idc','idd'})
  </code></pre>