Join two tables using more than one field / complicated logic

I have two tables I’d like to join together:

  • A list of users
  • A table that has activity for users

I want to create a histogram of usage (number of weeks where there is actvity), but for the users where there isn’t any usage I want rows that have a zero value.

I could easily do this in SQL like this:

select u.user_id, count(distinct a.week) as weeks
from users u
left join activity a on u.id = a.user_id and a.date >= ‘2020-01-01’
group by 1

When I try to help users do this via the query builder, I don’t have the option of putting the date logic in the join criteria and have to do it in the filter section. That turns it into an inner join. I also tried a custom expression adding a coalesce statement around date field in the activity table but that doesn’t work either.

I know that I can just tell people to do the inner join, but it makes any chart feel incomplete to me. Any ideas or suggestions for how to accomplish this?

Dan

1 Like

Hi @danwolch
Currently the join only allows a single match - there’s an issue open for adding more:
https://github.com/metabase/metabase/issues/11375 - upvote by clicking :+1: on the first post

But you can do what you’re trying to - just create Activity filtered question and save that, and then join with that question - example: