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"]')) != ''