"Taxpayer ID"-column in the Supplier html-form in 12.1.1
The "Taxpayer ID" field is found under the "Tax and Financial Information" section in the "Organization" part of the Suppliers html-form in R12.
The obvious answer is the ap_suppliers.num_1099 column but that is not the case. It is not hz_parties.jgzz_fiscal_code either.
Regards,
Olle