Flow/merge node - left & right join

The idea is:

right now the merge node has two modes that can be compared to SQL join:

  • merge by key - behaves like inner join
  • multiplex - behaves like outer join

Please add left join, which retains items from the first input when there’s no matching item in the second input

My use case:

My items have a field, say company_name, that I need to fill based on another field which might be empty, say, company_id.
I take all companies and try to merge it using company_id as the matching field.
If company_id is missing or otherwise not matching, I’d like to keep that item in the output.

I think it would be beneficial to add this because:

Left join is quite common in SQL and merge node looks like it’s supposed be something similar

Hi @mattesilver,

Merge by key should be a left join as far as I have seen.

I was doubting myself, so I checked it to be sure. I used an example from node page. and modified it so it would show the left join.

Hey Everyone! I would like to bring back this old feature request, as I think the left join functionality is widely useful for data transformations.

As I see it, the merge node still doesn´t have the full Left join functionality.

Left joins should keep all rows from input 1, but it should bring back all rows from input 2 that match. In the case of the merge node, it just brings the second.

Is there an easier way to do this?