{ "userCode": "abcd123", "response": 1 }
{ "userCode": "abcd123", "response": 1 }
{ "userCode": "abcd123", "response": 0 }
{ "userCode": "wxyz123", "response": 0 }
{ "userCode": "wxyz123", "response": 0 }
{ "userCode": "wxyz123", "response": 1 }

select userCode, response, count(*) as total
from response_table
group by userCode, response

abcd123, 0, 1 //user abcd123 responded 0 once
abcd123, 1, 2 //user abcd123 responded 1 twice
wxyz123, 0, 2 //user wxyz123 responded 0 twice
wxyz123, 1, 1 //user wxyz123 responded 1 once

{
 "aggs": {
  "users": {
   "terms": { "field": "userCode" },
   "aggs": {
    "responses" : {
     "terms": { "field": "response" }
    }
   }
  }
 }
}

{
 "data": {
  "properties": {
   "userCode": { "type": "string", "store": "yes", "index": "analyzed", "term_vector": "no" },
   "response": { "type": "integer", "store": "yes", "index": "analyzed", "term_vector": "yes" }
  }
 }
}