If the first part is correct, you can assign a variable to this select function and get the two values of the record:

let i := max(select Cats).cat
i.cat + " " + text(i.WeightDate)

Just change the first line to:

let i := last(select Cats order by weight)
i.cat + " - " + i.WeightDate

The change in line 1 adds the order by command so we select all records from Cats then order by weight then we pull the last one as that should be the heaviest. We have to make sure we don't put a field name after the select as that tells Ninox to only pull data from that one field and we need data from all fields.

In line 2 we don't need the text command for date fields.

I'm assuming that you will need to also filter the select so you can see weight by specific cat , so maybe something like:

let t := this;
let i := last(select Cats[name = t.name] order by weight)

I don't know what table you are in so I'm not sure you can just use a this command, but you get the idea.

If you already have a link to the Cats table from where ever you currently are then you don't need the select. If so then we can show you how to use the power of the relationship to get the data you need.

I hope this helps.