Lionel Elie Mamane committed a patch related to this issue. It has been pushed to "libreoffice-5-1":
http://cgit.freedesktop.org/libreoffice/core/commit/?id=43bca025961c4d78082e18efb95f9212b27f964b&h=libreoffice-5-1 tdf#92538 pgsql-sdbc make a reasonable sorting of types It will be available in 5.1.2. -- Stéphane Aulery