Solr field stats

http://localhost:8983/solr/collection1/
select?q=*:*&
wt=json&
fl=id,cat,manu,price&
indent=true&
omitHeader=true&
rows=2&
stats=true&
stats.field=price

{
  "response":{
    "numFound":1035,"start":0,
    "docs":[
      {
        "id":"GB18030TEST",
        "price":0.0},
      {
        "id":"SP2514N",
        "manu":"Samsung Electronics Co. Ltd.",
        "cat":["electronics", "hard drive"],
        "price":92.0}
     ]
  },
  "stats":{
    "stats_fields":{
      "price":{
        "min":0.0,
        "max":2199.0,
        "count":1019,
        "missing":16,
        "sum":9811.870031356812,
        "sumOfSquares":6068541.435907734,
        "mean":9.628920541076361,
        "stddev":76.60569132919564,
        "facets":{}
       }
     }
  }
}

Stats can be split into multiple groups

http://localhost:8983/solr/collection1/
select?q=*:*&
wt=json&
fl=id,cat,manu,price&
indent=true&
omitHeader=true&
rows=2&
stats=true&
stats.field=price&
stats.facet=inStock

{
  "response":{
    "numFound":1035,"start":0,
    "docs":[
      {
        "id":"GB18030TEST",
        "price":0.0},
      {
        "id":"SP2514N",
        "manu":"Samsung Electronics Co. Ltd.",
        "cat":["electronics",
          "hard drive"],
        "price":92.0}
     ]
  },
  "stats":{
    "stats_fields":{
      "price":{
        "min":0.0,
        "max":2199.0,
        "count":1019,
        "missing":16,
        "sum":9811.870031356812,
        "sumOfSquares":6068541.435907734,
        "mean":9.628920541076361,
        "stddev":76.60569132919564,
        "facets":{
          "inStock":{
            "":{
              "min":0.0,
              "max":30.0,
              "count":1003,
              "missing":11,
              "sum":4560.60000038147,
              "sumOfSquares":29922.26000770569,
              "mean":4.546959123012432,
              "stddev":3.0277159875652053,
              "facets":{}},
            "false":{
              "min":11.5,
              "max":649.989990234375,
              "count":4,
              "missing":0,
              "sum":1161.3900032043457,
              "sumOfSquares":653369.2541528536,
              "mean":290.3475008010864,
              "stddev":324.63444532124953,
              "facets":{}
            },
            "true":{
              "min":0.0,
              "max":2199.0,
              "count":12,
              "missing":5,
              "sum":4089.880027770996,
              "sumOfSquares":5385249.921747174,
              "mean":340.823335647583,
              "stddev":602.3683083752779,
              "facets":{}
            }
          }
        }
      }
    }
  }
}

Note that the sum of stats from each facet equals the facet count of the total.

Example:

  1019  =       1003       +            4          +       12
(count) = (count:facet:"") + (count:facet:"false") + (count:facet:"true") 


Same is true of any other stat like

2199.0 = max (    30.0,      649.989990234375,       2199.0    ) 
(max)  = max (max:facet:"", max:facet:"false", max:facet:"true")