[Koha] Report connecting bibliographic records and holdings

[Biblioteca FIUNER]

Dear Sirs, we need a report that allows us to connect the information in a
bibliographic record with the number of copies associated with it. We use
the following syntax as a base, but we're missing a total number of copies
per title: SELECT
biblionumber,
ExtractValue(metadata,'//datafield[@tag="100"]/subfield[@code="a"]') as
Autor, ExtractValue(metadata,'//datafield[@tag="260"]/subfield[@code="c"]')
as Añoedición, ExtractValue(metadata,'//datafield[@tag="245"]/*') as
Titulo, ExtractValue(metadata,'//datafield[@tag="250"]/*') as
Edicion,ExtractValue(metadata,'//datafield[@tag="260"]/subfield[@code="b"]')
 as Editorial, ExtractValue(metadata,'//datafield[@tag="020"]/*') as ISBN,
ExtractValue(metadata,'//datafield[@tag="690"]/subfield[@code="a"]') as
Asignatura,
ExtractValue(metadata,'//datafield[@tag="690"]/subfield[@code="x"]') as
CarrerayCondicion,
extractValue(metadata,'//datafield[@tag="690"]/subfield[@code="y"]') as
Añoplanificación
FROM biblio_metadata
WHERE (ExtractValue(metadata,
'//datafield[@tag="690"]/subfield[@code="a"]')) != ''
      AND length(ExtractValue(metadata,
'//datafield[@tag="690"]/subfield[@code="9"]')) != ''
Thank you in advance for any response.

Lic. Brenda Ramirez

*Biblioteca "Dr. Eduardo A. Barbagelata"*

 biblioteca.ingenieria at uner.edu.ar

 +54 343 4571839  (de lun. a vie. de 8 a 18 hs.)

  https://biblioteca-fing.uner.edu.ar/cgi-bin/koha/opac-main.pl

  https://campus.ingenieria.uner.edu.ar/enrol/index.php?id=443

  De* lunes a viernes de 8 a 18 hs.*