ORA-02063 when selecting over DBLINK

Question

Hey, I'm having an issue where a complex select is returning a 02063 (it has an 'invalid identifier' on a column that clearly exists)
I would post the query but it's pretty large and joins 2 views. One of the views selects through a dblink, so it's imbedded pretty far in. I cannot isolate parts of the query that are causing the issue because of this.
What I wanted to know is the best way to write the link or the view to avoid these parser issues. Here's the complete error message I get as well as the script for the link:
ORA-00904: "A"."BUYING_MEMBER_ID": invalid identifier
ORA-02063: preceding line from WEBAPP6
create public database link "WEBAPP6.REGRESS.RDBMS.DEV.US.ORACLE.COM"
connect to ABC_WEBAPP
identified by "<pwd>"
using 'abcdb';
And the script for the view which uses the link:
SELECT a.ID member_id, a.NAME member_nm, a.url member_url, a.address_1,
a.address_2, a.city, a.fda_license, a.is_abc_board_member,
a.is_gsabc_board_member, a.is_abc_foundation_board_member,
c.short_name state_id, d.code zip_cd, e.code county_cd, a.phone_main,
a.phone_alt, a.fax, b.financial_ctr_id, b.benchmarking_ctr_id,
b.piag_ctr_id
FROM MEMBER@webapp6 a LEFT OUTER JOIN lu_member_dw b ON a.ID = b.member_id
JOIN state@webapp6 c ON a.state_id = c.ID
JOIN zip@webapp6 d ON a.zip_id = d.ID
JOIN county@webapp6 e ON a.county_id = e.ID
UNION
SELECT member_id, member_nm, member_url, ' ', ' ', ' ', ' ', ' ', ' ', ' ',
' ', ' ', ' ', ' ', ' ', ' ', financial_ctr_id, benchmarking_ctr_id,
piag_ctr_id
FROM lu_member_dw
WHERE member_id NOT IN (SELECT ID
FROM MEMBER@webapp6)

Answer 1

Always use alias names! If you have no alias name, create one. Without alias the database can just guess where this column is coming from.
Consider UNION ALL instead of union (not sure if it is the same result).
Consider to create a view on the other database that joins all tables and that you access over the DB-Link.
There are also some hints that influences where the selects are executed (on your DB or on the other one), however I forgot the name of them (PUSH_SUB?).