Hi Feifei,

A single column can only be configured with a single lookup, as you've discovered. You can set custom query metadata to clone the column (via the Alias Column button, not shown in the screenshot in the docs), which can be configured with a different lookup. The lookup target could be a custom query which would allow you to specify the SQL.

https://www.labkey.org/wiki/home/Documentation/page.view?name=metadataSql

Thanks,
Josh