How to get aggregation bucket keys in the term query block

[Shrikanth_M (Shrikanth)]

How to get aggregation bucket keys in the term query block in the same query?

Query

{
   "size": 0,
   "query": {....},
   "aggs": {
      "customerId": {
		 "composite": {
			"sources": [
			   {
				  "customerId": {
					 "terms": {
						"field": "customerId"
					 }
				  }
			   }
			]
		 },
		 "aggs": {
			"items_count": {
			   "cardinality": {
				  "field": "itemId"
			   }
			},
			"item_count_bucket_sort": {
			   "bucket_sort": {
				  "size": 2,
				  "sort": [
					 {
						"items_count": {
						   "order": "desc"
						}
					 }
				  ]
			   }
			}
		 }
	  }
   }
}

Output

{
   "took": 71,
   "timed_out": false,
   "_shards": {
	  "total": 15,
	  "successful": 15,
	  "skipped": 0,
	  "failed": 0
   },
   "hits": {
	  "total": 173980,
	  "max_score": 0,
	  "hits": [x]
   },
   "aggregations": {
	  "customerId": {
		 "after_key": {
			"customerId": "CUST000000010"
		 },
		 "buckets": [
			{
			   "key": {
				  "customerId": "CUST000000007"
			   },
			   "doc_count": 12,
			   "items_count": {
				  "value": 4
			   }
			},
			{
			   "key": {
				  "customerId": "CUST000000008"
			   },
			   "doc_count": 10,
			   "items_count": {
				  "value": 4
			   }
			}
		 ]
	  }
   }
}

In the above output received customerId, need to set in the term query block.