Mongo Db How to detect error in pipeline?

Question

I need to join two collection with two conditions.

products:
{
  ...
  sku: "4234",
  organizationId: ObjectId("asdasdasd);
  ...
};

order_history:
{
  ...
  itemSku: "4234",
  organizationId: ObjectId("asdasdasd);
  ...
}

I chose pipeline approach:

$lookup: {
  from: 'order_history',
  let: { foreign_sku: "$itemSku", foreign_organizationId: "$organizationId" },
  pipeline: [
    {
      $match: {
        $expr: {
          $and: [
            { $eq: ["$organizationId", "$$foreign_organizationId"] },
            { $eq: ["$sku", "$$foreign_sku" ] }
          ]
        }
      }
    }
  ],
  as: 'order_history'
}

I wrote it on base of Mongo Documentation, but my conditions are ignored. I have scalar multiplication in result. Where is my mistake?

You need to join order_history with products. So you have added from:'order_history' in lookup. But let variables should be from product collection, not from order history collection. Your $itemSku and $organizationId are coming from order_history colelction — varman
– varman, Commented Jul 25, 2021 at 16:03

varman · Accepted Answer · 2021-07-25 16:07:20Z

2

I already mention in the comment and the code is below

db.products.aggregate([
  {
    $lookup: {
      from: "order_history",
      let: {
        foreign_sku: "$sku",
        foreign_organizationId: "$organizationId"
      },
      pipeline: [
        {
          $match: {
            $expr: {
              $and: [
                {
                  $eq: [
                    "$organizationId",
                    "$$foreign_organizationId"
                  ]
                },
                {
                  $eq: [
                    "$itemSku",
                    "$$foreign_sku"
                  ]
                }
              ]
            }
          }
        }
      ],
      as: "order_history"
    }
  }
])

Working Mongo playground

answered Jul 25, 2021 at 16:07

varman

8,9226 gold badges25 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Mongo Db How to detect error in pipeline?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related