Hi all,
I am trying to use Metabase, but I got some problems when I want to join 2 collections.
[{
"$lookup":
{
"from": "Campaign",
"localField": "Conversion.campaign_id",
"foreignField": "Campaign.campaign_id",
"as":"as1"
}
},
{
"$unwind":"$as1"
},
{
"$project":
{
"campaign_id":"$as1.campaign_id",
"campaign_name":"$as1.campaign_name"
}
}]
This above one shows me that:
You can see _id will be matched with all of each name and that's not what I want: I just want an _id matches with only one campaign_name
So then, I try this code:
[{
"$lookup":
{
"from": "Campaign",
"localField": "Conversion.campaign_code",
"foreignField": "Campaign.campaign_code",
"as":"as1"
}
},
{
"$replaceRoot": { "newRoot": { "$mergeObjects": [ { "$arrayElemAt": { "as1", 0 } }, "$$ROOT" ] } }
},
{
"$unwind":"$as1"
},
{
"$project":
{
"campaign_id":"$as1.campaign_id",
"campaign_name":"$as1.campaign_name"
}}
]
and then got the error:
Can anyone help me?
Thank you for reading carefully