Hi, On 01/09/2012 03:30 PM, Mike Hafen wrote:
I've seen UNION used to join those two tables in queries. I'm imaginning something like:
SELECT YEAR(issuedate), MONTH(issuedate), categorycode, COUNT(DISTINCT borrowernumber) FROM ( SELECT issuedate,categorycode,borrowernumber FROM old_issues UNION ALL SELECT issuedate,categorycode,borrowernumber FROM issues ) LEFT JOIN borrowers USING (borrowernumber) GROUP BY YEAR(issuedate), MONTH(issuedate), categorycode;
A UNION ALL is indeed a valid way to do it. Regards, Galen -- Galen Charlton Director of Support and Implementation Equinox Software, Inc. / The Open Source Experts email: gmc@esilibrary.com direct: +1 770-709-5581 cell: +1 404-984-4366 skype: gmcharlt web: http://www.esilibrary.com/ Supporting Koha and Evergreen: http://koha-community.org & http://evergreen-ils.org