Aggregate multiple dynamically selected columns in Ecto (without group by)

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3

Ah thanks, I had tried using select_merge before without luck, but your comment made me look at it again—here is what ended up working for me:

query = from(i in "data", select: %{})
fields = [:income_a, :income_b]
# fields = [:tax_a, :tax_b]
query = 
  Enum.reduce(fields, query, fn field, query -> 
    select_merge(query, [i], %{^Atom.to_string(field) => sum(field(i, ^field))})
  end)
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