Custom expression question

I have 2 tables. Table 1 is transaction table which will have registrations from various cities. Table 2 is static table which has city-wise expected Registrations. I wanted to display overall % Registration which would be Total Registrations/ (sum of expected registrations for each city). I am trying to do this using custom expression but can’t figure out. I can easily write a native query and do this but just wanted to avoid as I am expecting lot of filters in future.

Ideally if I am able to do a expression like count/sum(distinct expected_registrations) it would give me the result but I think this is not allowed in custom expression. Any tricks?

Hi @jiwnaiakbar
I’m just trying to understand what expected_registrations is - the column type.
Since from your text, I would guess that Count / Distinct([expected_registrations]) should work, but that translates the Distinct() function in count(distinct column), which is probably not what you’re after.

I don’t remember seeing a request for sum(distinct column), which perhaps should be handled in Metabase like Sum(Distinct([column])) - you’re welcome to open a feature request:

Hi @flamber thnx for the reply. Count / Distinct([expected_registrations]) will not work because I will have multiple cities with each city having expected_registrations number.

Below is sample of both the tables:

Table 1
CityId City Name ExpectED Registrations
1 City 1 10
2 City 2 5
3 City 3 15
4 City 4 6
5 City 5 50
Registration ID Name City
1 User1 City 1
2 User2 City 2
3 User3 City 1
4 User4 City 1
5 User5 City 3
6 User6 City 4
7 User7 City 1
8 User8 City 2
9 User9 City 5
10 User10 City 1

So Overall % Registration would be Count(Registration ID)/sum(10+5+15+6+50) i.e. 11%

@jiwnaiakbar Yeah, I can definitely see the use case - and you have described it very well with the table, so please open a feature request on that.

Done. :slight_smile:

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