DB Error when Exporting Contact Using "Merge Household" Option

I get a DB Error (image) when exporting contact search results using the "Merge Household Members into their Households" option. Error occurs with 4.7.1 & 4.7.2. It appeared after we upgraded from 4.6.10. I duplicated it in both the Drupal and WordPress sandboxes. The error can be reproduced by searching for contacts and exporting contacts using the "Merge Household Members into their Households" option.

See Stack Exchange Post.