jason.o
Referring to relationships in calculations
Where Post has_many Comments, I’d like to define a calculation in Post that essentially produces the following query. What’s the expression that I should define?
select *, coalesce(c.title, p.title) as title from Post p
left join Comments c
on c.post_id = p.id
Apparently, this doesn’t work.
calculate :combined_title, :string, expr(coalesce(comments.title, title))
Marked As Solved
zachdaniel
You can reference it, but you can’t terence it “raw” like that. You use the reference in the expression, and interpolate that into the fragment string with ?. In that specific instance it would look like this:
calculate :date, :utc_datetime, expr(instance.revised_date || original_date)
Post
|> Ash.Query.load([:date, :instance])
|> Ash.Query.filter(fragment("date_part('year',?)", date) == 2023)
|> Api.read()
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zachdaniel
My pleasure! You as well 
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