Can elasticsearch do GROUP BY multi fields and ORDER BY count?

Elastic Stack Elasticsearch
2

Hi rookie1.
Yes, you can group data by multiple fields. One difference from SQL is that that results can be a tree structure with hierarchy rather than thinking of them like a flattened table of results.
You would use the terms aggregation to group information. For example, given an index of investment data field1 might be investor and field 2 might be the company invested in:

GET /crunchbase/_search
{
  "size":0,
  "aggregations": {
	"first_by_investor": {
	  "terms": {
		"field": "investor"
	  },
	  "aggregations": {
		"then_by_company": {
		  "terms": {
			"field": "company"
		  }
		}
	  }
	}
  }
}

The results are a hierarchy like this (default sort size is by number of docs):

...	
  "aggregations" : {
	"first_by_investor" : {
	  "buckets" : [
		{
		  "key" : "New Enterprise Associates",
		  "doc_count" : 445,
		  "then_by_company" : {
			"buckets" : [
			  {
				"key" : "PatientKeeper",
				"doc_count" : 5
			  },
			  {
				"key" : "SolFocus",
				"doc_count" : 5
			  }
              ...
			},
			{
			  "key" : "SV Angel",
			  "doc_count" : 436,				  
			   ...
			}
    ]