MongoDB lookup with string and objectId

Jaimin Patel answered on February 15, 2023 Popularity 6/10 Helpfulness 4/10

answer MongoDB lookup with string and objectId

MongoDB lookup with string and objectId

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// First Approach convert string field to ObjectId ('$toObjectId') and match 
Duel.aggregate([
      { $match: query },
      { '$addFields': { 'photo1Id': { '$toObjectId': '$photo1' }, 'photo2Id': { '$toObjectId': '$photo2' } } },
      {
        $lookup: {
          from: 'photoschemas',
          localField: 'photo1Id',
          foreignField: '_id',
          as: 'photo1Info'
        }
      },
      {$unwind: '$photo1Info'},
      {
        $lookup: {
          from: 'photoschemas',
          localField: 'photo2Id',
          foreignField: '_id',
          as: 'photo2Info'
        }
      },
      {$unwind: '$photo2Info'}
}]

// Second Approach
db.role.aggregate([
  { "$lookup": {
    "from": "user",
    "let": { "userId": "$_id" },
    "pipeline": [
      { "$addFields": { "userId": { "$toObjectId": "$userId" }}},
      { "$match": { "$expr": { "$eq": [ "$userId", "$$userId" ] } } }
    ],
    "as": "output"
  }}
])

Popularity 6/10 Helpfulness 4/10 Language whatever

Source: stackoverflow.com

Tags: mongodb-lookup objectid string whatever

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Contributed on Feb 15 2023

Jaimin Patel

0 Answers Avg Quality 2/10

MongoDB lookup with string and objectId

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