[Tutor] Question on a select statement with ODBC

[Al Bull]

Windows 7.0
Python 3.3.4

I am accessing a database table via ODBC.   The table I am accessing can
have multiple records per ord_dbasub.  Is there a way I can structure the
select statement to retrieve only the most current record (based on
ord_date)?

I used to program in PL/I and assembly in the old days but my knowledge of
SQL and Python is still pretty limited.   Here is what I have so far..

import pyodbc
cnxn = pyodbc.connect("DSN=Quickfill DEMO Database")
cursor = cnxn.cursor()

ord_rows = cursor.execute("select ord_dbasub, ord_pub,
ord_date,ord_service,"
                          "ord_agency, ord_woa, ord_status,"
                          "ord_channel, ord_source, ord_giftcomp,"
                          "ord_cnreason "
                          "from ord "
                          "Where ord_pub='QWKFIL'"
                          "order by ord_dbasub, ord_date").fetchall()

for row in ord_rows:
   # Print for testing.  Remove later
   print (row.ord_dbasub, row.ord_date, row.ord_pub)
   # Add code here to find the most recent order per DBASUB and delete other
orders
   # Also add exclusion code to be applied to survivor record


This code works so far.   I just need to determine how to remove all but the
most current record per ord_dbasub.    Assuming I can't remover it via the
select statement I'll have to traverse the array (Tuples in Python,
correct?) and remove the ones I don't need.   What's the best way to do
that?

I have to admit that the concept of tuples & dictionaries has me a little
bit confused.    I'm used to working with arrays and arrays of structures.

Thanks in advance for your help!


Al Bull, Chief Technology Officer/Owner
Publishers Data Management Group


a.bull at pubdmgroup.com
815-732-5297