Sort DataFrame by the greater of multiple columns

[bkamins]

This is the approach for plain DataFrames.jl. With DataFramesMeta.jl do:

julia> using DataFramesMeta

julia> @orderby(df, -max.(:A, :B))
4×2 DataFrame
 Row │ A      B
     │ Int64  Int64
─────┼──────────────
   1 │    19     30
   2 │    18     25
   3 │    22     17
   4 │    21     18