How to use Aggregation correctly

I want to count the quantity of bought products in all orders for a special product but only get 3 back as the result in an appscript. Doesnt matter which product I use. That is the codesnippet I am using:

{% set criteria = {
    'associations': {
        'lineItems': {
            'productId': page.product.id
        }
    },
    'aggregations': [{
        "name": "count-lineItems-quantity",
        "type": "count",
        "field": "order.lineItems.quantity"
    }]
}
%}

{% set orders = services.repository.search('order', criteria) %}
{% do debug.dump(orders.getAggregations.get('count-lineItems-quantity')) %}

Maybe someone can point me in the right direction and can show me what I am doing wrong.

Cheers,

Danny

Solution

You probably currently are only getting the count of unique line items, not the sum of quantities for each line item.

First, I would use the order_line_item repository, unless you need order specific data. I assume you're trying to filter the results by page.product.id? Then I would use a filter aggregation to only get line items belonging to a specific product. Then you could have a nested aggregation to sum all the quantity fields of occurrences of line items with that referencedId.

{
    "aggregations": [
        {
            "name": "my-filter",
            "type": "filter",
            "filter": [
                { 
                    "type": "equals", 
                    "field": "referencedId", 
                    "value": "7594ed63b27345d39f61c82f0b4d4e52" // page.product.id
                }
            ],
            "aggregation": {
                "name": "total-quantity",
                "type": "sum", 
                "field": "quantity"
            }
        }
    ]
}

If you want the sums for all products, you could have a nested terms aggregation so you get buckets of quantity sums per referencedId

{
    "aggregations": [
        {
            "name": "my-filter",
            "type": "filter",
            "filter": [
                { 
                    "type": "equals", 
                    "field": "type", 
                    "value": "product"
                }
            ],
            "aggregation": {  
                "name": "per-line-item",
                "type": "terms",
                "field": "referencedId",
                "aggregation": {
                    "name": "total-quantity",
                    "type": "sum", 
                    "field": "quantity"
                }
            }
        }
    ]
}