ElasticSearch Aggregation on nested field with bucketing on parent id - elasticsearch

Question

Following is my doc structure
'Order': {
u'properties': {
u'order_id': {u'type': u'integer'},
'Product': {
u'properties': {
u'product_id': {u'type': u'integer'},
u'product_category': {'type': 'text'},
},
u'type': u'nested'
}
}
}
Doc1
"Order": {
"order_id": "1",
"Product": [
{
"product_id": "1",
"product_category": "category_1"
},
{
"product_id": "2",
"product_category": "category_2"
},
{
"product_id": "3",
"product_category": "category_2"
},
]
}
Doc2
"Order": {
"order_id": "2",
"Product": [
{
"product_id": "4",
"product_category": "category_1"
},
{
"product_id": "1",
"product_category": "category_1"
},
{
"product_id": "2",
"product_category": "category_2"
},
]
}
I want to get following output
"aggregations": {
"Order": [
{
"order_id": "1"
"category_counts": [
{
"category_1": 1
},
{
"category_2": 2
},
]
},
{
"order_id": "1"
"category_counts": [
{
"category_1": 2
},
{
"category_2": 1
},
]
},
]
}
I tried using nested aggregation
"aggs": {
"Product-nested": {
"nested": {
"path": "Product"
}
"aggs": {
"category_counts": {
"terms": {
"field": "Product.product_category"
}
}
},
}
}
It does not give output for each order but gives combined output for all orders
{
"Product-nested": {
"category_counts": [
"category_1": 3,
"category_2": 3
]
}
}
I have two questions:
How to get the desired output in above scenario?
What if instead of single product_category I have an array of
product_categories then how will we achieve the same in this
scenario?
I am using elasticsearch >= 5.0

Answer 1

I have an idea but i dont think its the best one..
you can make a terms aggregation on the "order_id" field, then a sub nestes aggregation on "Product.product_category".
somthing like this :
{
"aggs": {
"all-order-id": {
"terms": {
"field": "order_id",
"size": 10
},
"aggs": {
"Product-nested": {
"nested": {
"path": "Product"
},
"aggs": {
"all-products-in-order-id": {
"terms": {
"field": "Product.product_category"
}
}
}
}
}
}
}
}
sorry its lock bit messy i'm not so good with this answer editor