I just noticed something else with my "In" syntax. If you put the IN clause into a JOIN, you can use the LIKE against the original source table for a set based approach instead of concatenating.
CREATE TABLE tblAccount (
pkAccountId int,
Acctnum varchar(20),
fkOverDraftId1 int,
fkOverDraftId2 int)
SELECT main.Acctnum, qry.Acctnum
FROM tblAccount main
INNER JOIN tblAccount qry ON qry.pkAccountid IN (main.fkOverDraftId1, main.fkOverDraftId2)
WHERE qry.AcctNum LIKE '%123%'