How To Return The Variant Values Of Each Product If That Product Is A Variant?

I have a database in MongoDB like this {'productId' : 1, 'isVariant': 1, 'variantId' : 1, 'attributeSet' : [ { 'name' : 'Capacity', 'value' : '500

Solution 1:

You should be able to achieve this using $unwind and $group in your aggregation pipeline. This first flattens each attribute into a single document and on those you can group by the attribute value.

Finally, you can use $project to get the desired name for attributeValue:

db.collection.aggregate([
  {
    $unwind: "$attributeSet"
  },
  {
    $group: {
      _id: "$attributeSet.value",
      data: {
        "$addToSet": {
          productId: "$productId"
        }
      }
    }
  },
  {
    "$project": {
      _id: 0,
      data: 1,
      attributeValue: "$_id"
    }
  }
])

See this simplifed example on mongoplayground: https://mongoplayground.net/p/VASadZnDedc