How to case insensitivity check in combination with lookup/graphLookup?-CodePudding

I have a query implemented in the below link wherein I am trying to get all the depots based on the city values present in charge_level_key inside contracts. In other words, each string value in charge_level_key is a city that has to be matched with the depots and the corresponding depots should be fetched.

The current implementation is working with case sensitive. I need to make it work as the same way with case insensitivity. How would I do that

https://mongoplayground.net/p/ZH6K5gkJxrs

Thanks in advance

CodePudding user response：

With regular $lookup you can use a pipeline with $toLower:

db.contracts.aggregate([
  {$match: {_id: ObjectId("630c9e23fb146c4b3b801b9e")}},
  {$set: {
      charge_level_key: {$map: {input: "$charge_level_key", in: {"$toLower": "$$this"}}}
  }},
  {
    $lookup: {
      from: "depots",
      let: {charge_level_key: "$charge_level_key"},
      pipeline: [
        {$match: {
            $expr: {
              $in: [{$toLower: "$city"}, "$$charge_level_key"]
            }
          }
        }
      ],
      as: "depots"
    }
  },
  {$sort: {count: -1}}
])

See how it works on the playground example