POST /empty-test-00001/_bulk
{ "index" : { "_index" : "empty-test-00001", "_id" : "1" } }
{ "l1": 1, "l2":{"l2": []}}
POST /_plugins/_sql
{
  "query" : "select * from empty-test-00001"
}

# Result
{
  "error": {
    "type": "IllegalStateException",
    "reason": "There was internal problem at backend",
    "details": "No type found for field: l2.l2."
  },
  "status": 503
}