Don’t know Oracle, but in MySQL I usually make use of list attribute of cfqueryparam:
<cfquery name="othertest" datasource="htc">
select c.obid, c.username, a.loginname
from table1 c, table2 a
where c.obid= a.obid
and a.obid IN (<cfqueryPARAM value = "#getobj#" CFSQLType = "CF_SQL_INTEGER" list="true" separator=";">)
</cfquery>
To tacle down strange SQL results, I sometimes copy the SELECT statement from cfquery to a raw cfoutput code (getting rid of the cfqueryparam), then I look at the page result and copy/paste the output directly into my SQL-Client (in my case heidisql) to check the results. That made me have some facepalms already
Example:
<cfquery name="othertest" datasource="htc">
select c.obid, c.username, a.loginname
from table1 c, table2 a
where c.obid= a.obid
and a.obid in (#preserveSingleQuotes(getobj)#)
</cfquery>
<cfoutput>
select c.obid, c.username, a.loginname
from table1 c, table2 a
where c.obid= a.obid
and a.obid in (#preserveSingleQuotes(getobj)#)
</cfoutput>
The last cfoutput part I simply copy from the browser result, and paste it to another SQL-Client to check the results of that exact SQL statement.