MdNazmulIslam
November 16, 2023
149 views
0 votes
2 Answers

{
    "offers" : [
        {
            "name" : "min",
            "prices" : [
               8, 15, 18
            ]
        },
        {
            "name" : "max",
            "prices" : [
               9, 11, 18
            ]
        }
    ],
    "nl" : [
        2, 4, 6, 7
    ]
}

update aggregation not working $in. I have tried on the two ways

[
    {
      $set: {
          offers: {
              $cond: {
                  if: {
                        "nl": {$in: [7]}
                  },
                   then: {
                          $concatArrays: ["$offers", []]
                      },
                  else: {
                        $concatArrays: ["$offers", [{
                                "name" : "minimal",
                                "prices" : []
                            }]]
                      }
              }
          }
      }
    },
   ]

The code below is not working and not showing any error.

[
    {
      $set: {
          offers: {
              $cond: {
                  if: {
                        $in: ["$nl", 7]
                  },
                   then: {
                          $concatArrays: ["$offers", []]
                      },
                  else: {
                        $concatArrays: ["$offers", [{
                                "name" : "minimal",
                                "prices" : []
                            }]]
                      }
              }
          }
      }
    },
   ]

I want to cancat with offers array according to the exi/stence of 7 in the field "nl". Please help me. I am trying to solve this problem during 5 hours.

Answers

- Alex
- November 16, 2023 at 5:16 pm
- 0 votes
0
$in on aggregation is on this syntax: (see MongoDb Docs)
```
{ $in: [ <expression>, <array expression> ] }
```
You need to inverse $in condition. Like this:
```
$in: [7, "$nl"]
```
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- jQueeny
- November 16, 2023 at 5:29 pm
- 0 votes
0
I’m not sure what your expected outcome is but you need to pass the number 7 as the first argument (a valid expression) and the array to compare against as the second (a valid expression that resolves to an array) like so:
```
{
    $set: {
      offers: {
        $cond: [
          {
            $in: [
              7,
              "$nl"
            ]
          },
          {
            $concatArrays: [
              "$offers",
              []
            ]
          },
          {
            $concatArrays: [
              "$offers",
              [
                {
                  "name": "minimal",
                  "prices": []
                }
              ]
            ]
          }
        ]
      }
    }
  }
```
See HERE for a working example.
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