(Recommendations from Jean Pajerek and Joanne Leary)
The first subject heading in the record is generally meant to correlate with the dominant subject matter of the book or whatever, but this is not always possible because there are some subject headings that have to be assigned in pairs, like United States--Foreign relations--China and China--Foreign relations--United States.
There are 4 LC subject headings in this record, and numerous other subject terms as well. To find the first subject term in a record, I recommend using that number 1 in the ord field.
For example:
SELECT DISTINCT
SM.instance_hrid,
SM.field,
SM.ind2,
SM.ord,
SM.sf,
SM."content"
FROM
public.srs_marctab SM
WHERE SM.instance_hrid = '15309598'
AND SM.field LIKE '6%%'
AND SM.ord='1'
AND SM.ind2='0'
Further, to