Often, you’ll find yourself wanting to sort based on a metric’s calculated value. For our car sales analytics dashboard, we may want to build a bar chart of sales by car color, but order the bars by the average price, ascending.

We can do this by adding a metric to our bucket, and then referencing that metric from the order parameter:

GET /cars/transactions/_search
{
    "size" : 0,
    "aggs" : {
        "colors" : {
            "terms" : {
              "field" : "color",
              "order": {
                "avg_price" : "asc" 
              }
            },
            "aggs": {
                "avg_price": {
                    "avg": {"field": "price"} 
                }
            }
        }
    }
}

This lets you override the sort order with any metric, simply by referencing the name of the metric. Some metrics, however, emit multiple values. The extended_stats metric is a good example: it provides half a dozen individual metrics.

If you want to sort on a multivalue metric, you just need to use the dot-path to the metric of interest:

GET /cars/transactions/_search
{
    "size" : 0,
    "aggs" : {
        "colors" : {
            "terms" : {
              "field" : "color",
              "order": {
                "stats.variance" : "asc" 
              }
            },
            "aggs": {
                "stats": {
                    "extended_stats": {"field": "price"}
                }
            }
        }
    }
}

In this example we are sorting on the variance of each bucket, so that colors with the least variance in price will appear before those that have more variance.