Native script for joining 2 mongodb databases in Metabase

Hello all, I am using the community edition of Metabase. I have 2 mongodb databases and need to do a join between the two. Wanted to know if the syntax below is correct, where DB02 is the 2nd DB and the first DB is setup in the Native script window from the dropdown at the top LHS. clientID is a field in DB01, Partner is the table in DB02, and username is the field in partner with whom the join needs to be made.

The query seems to go through but the match is not happening.

    "$lookup": {
      "from": "DB02.Partner",
      "let": {
        "let_clientId_55717": "$clientId"
      "pipeline": [
          "$match": {
            "$expr": {
              "$eq": [
      "as": "join_alias_Partner"
  }, ...

hi, why don't you use the latest version where this is supported natively?

Am already using v0.46

Can’t you do joins?

Simple joins are not working. So have to use native code.

I'm facing the same issue:
Simple joins with OjbectId fails.
Same result with native code, even when converting to string.
An example of a working join with mongodb collections would be very appreciated.
Version 0.46: Metabase 46
"MongoDB is quite popular as a data source for Metabase, but our driver wasn’t living up to the popularity. So we made humongous improvements to it, including a smarter schema sync process to handle variable keys, support for models, fast joins, custom expressions, additional aggregations, and more."