search - Elasticsearch. Range query for strings with dashes -

i'm using elasticsearch data have string-field date values, this:

"2016-01-25 18:40:18.933"

i'm trying use range filter getting values date date. example:

    "query" : {         "filtered" : {             "query" : {                 "range" : {                     "createddate" : {                         "gte": "2015-11-01",                          "lte": "2016-01-25"                     }                 }             }         }       }     } 

but results doesn't contain values "createddate": "2015-12-14 20:28:23.557"

if use "gte": "2015" or "gte": "2014-12-31", values "createddate": "2015-12-14" included in results.

what's wrong in query?

if want able run range queries on dates, need map field date field, otherwise won't work expect. in mapping shared, createddate string. need wipe index , create new 1 proper mapping createddate field, this:

curl -xpost localhost:9200/documents -d '{    "mappings": {       "order": {          "properties": {              "createddate": {                 "type": "date"              }          }       }    } }'  

then can reindex data , range query work expected.