-- no low / hi corner cases for UUIDs SELECT '000000000000-0000-0000-0000-00000000'::uuid , 'ffffffffffff-ffff-ffff-ffff-ffffffff'::uuid;

-- and all possible version / variant combinations are valid SELECT g, to_hex(g), to_hex(h) , ('123e4567-e89b-' || to_hex(g) || '2d3-' || to_hex(h) || '456-426614174000')::uuid , ('ffffffff-ffff-' || to_hex(g) || 'fff-' || to_hex(h) || 'fff-ffffffffffff')::uuid , ('00000000-0000-' || to_hex(g) || '000-' || to_hex(h) || '000-000000000000')::uuid FROM generate_series(0, 15) g , generate_series(0, 15) h;