Here's the query to find all the titles that have a specific NLS subject / broad descriptor in the MARC tag 072. The first example will return all DB and BR titles that have AFAMAF (African American Topics adult fiction):
Advanced Search tab
MARC Tag - Tag - Begins - 072
MARC Tag - Subfield - Begins - a
MARC Tag - Data - Equals - AFAMAF
BibRec - KLAS ID - In - BR*,DB*
This second example will return all DB and BR titles that have either AFRKAF, AFRKAN, AFRKJF or AFRKJN in the 072 (Afrikaans Language, whether adult or juvenile, fiction or nonfiction):
MARC Tag - Tag - Begins - 072
MARC Tag - Subfield - Begins - a
MARC Tag - Data - Begins - AFRK
BibRec - KLAS ID - In - BR*,DB*
