update items set datelastseen = datelastborrowed
;
create temporary table old_returndate as
-select itemnumber,max(returndate)
+select itemnumber,max(returndate) as returndate
from old_issues
-group by itemnumber
+group by itemnumber,returndate
;
update items
-join old_issues on items.itemnumber=old_issues.itemnumber
+join old_returndate on items.itemnumber=old_returndate.itemnumber
set datelastseen = returndate
where returndate > datelastseen or datelastseen is null
;
+create temporary table old_issuedate as
+select itemnumber,max(issuedate) as issuedate
+from old_issues
+group by itemnumber,issuedate
+;
+update items
+join old_issuedate on items.itemnumber=old_issuedate.itemnumber
+set datelastborrowed = issuedate
+where datelastborrowed is null
+;
update old_issues set timestamp = returndate
};