Min() doesn't work on dates

[ela-b]

Loading JSON document from http://hackathon.services-autoscout24.de/id.php?asset=357322040163096... done.

$.*
[
{
"latitude": null,
"longitude": null,
"recorded_at": null
},
{
"latitude": 48.14695,
"longitude": 11.5347,
"recorded_at": "2014-10-31T18:25:22Z"
},
{
"latitude": 48.14695,
"GPS_SPEED": {"1": 0},
"longitude": 11.5347,
"recorded_at": "2014-10-31T18:25:21Z"
},
{
"latitude": 48.14775,
"longitude": 11.53441,
"recorded_at": "2014-10-31T18:22:47Z"
},
{
"latitude": 48.14695,
"GPS_DIR": 143.2,
"GPS_SPEED": {"1": 4001},
"longitude": 11.53467,
"recorded_at": "2014-10-31T18:23:03Z"
},
... (11166 more items)
]
$.recorded_at
[
null,
"2014-10-31T18:25:22Z",
"2014-10-31T18:25:21Z",
"2014-10-31T18:22:47Z",
"2014-10-31T18:23:03Z",
... (11166 more items)
]
min($.recorded_at)
min() arg is an empty sequence