[Koha] Duplicate ISBN report modification

[MJ Ray]

On Wed, 15 Aug 2018 09:43:50 -0400
Cab Vinton <bibliwho at gmail.com> wrote:

> Figured a subquery would work as a way to first restrict the results
> to records where Branch A owns at least one copy, & then to perform
> the search for duplicate records on the resulting subset.

Oh I see. So do you mean something like

SELECT GROUP_CONCAT(b.biblionumber SEPARATOR ', ') AS biblionumbers,
b.title, b.author, GROUP_CONCAT(i.isbn SEPARATOR ', ') AS isbns
FROM biblio b
WHERE b.biblionumber IN
  (SELECT m.biblionumber
   FROM items m
   WHERE m.homebranch = <<Library|branches>> )
LEFT JOIN biblioitems i ON (i.biblionumber=b.biblionumber)
GROUP BY CONCAT(substr(b.title,0,9),"/",i.isbn)
HAVING COUNT(CONCAT(substr(b.title,0,9),"/",i.isbn))>1

?  That's probably horribly inefficient and I've not tested it because
I suspect I've still misunderstood.

Hope that helps,
-- 

MJR http://mjr.towers.org.uk/
Member of http://www.software.coop/ (but this email is my personal view
only)