fix: Sanitize distinct in joins (#168)

Author: jechol

lib/join.ex

@@ -697,7 +697,7 @@ defmodule AshSql.Join do
       distinct =
         Enum.flat_map(sort, fn
           {attribute, direction} when is_atom(attribute) ->
-            [{direction, attribute}]
+            [{attribute, direction}]
 
           {%Ash.Query.Calculation{} = calculation, direction} ->
             resource = joined_query.__ash_bindings__.resource
@@ -707,14 +707,16 @@ defmodule AshSql.Join do
 
             case AshSql.Expr.dynamic_expr(calc_query, expression, calc_query.__ash_bindings__) do
               {result, _} when is_atom(result) -> []
-              {dynamic_expr, _} -> [{direction, dynamic_expr}]
+              {dynamic_expr, _} -> [{dynamic_expr, direction}]
             end
 
           _ ->
             []
         end) ++
           Ash.Resource.Info.primary_key(joined_query.__ash_bindings__.resource)
 
+      distinct = distinct |> AshSql.Sort.sanitize_sort()
+
       if joined_query.__ash_bindings__.sql_behaviour.multicolumn_distinct?() do
         from(row in joined_query,
           distinct: ^distinct

lib/sort.ex

@@ -463,7 +463,7 @@ defmodule AshSql.Sort do
     Map.update!(query, :__ash_bindings__, &Map.put(&1, :sort_applied?, true))
   end
 
-  defp sanitize_sort(sort) do
+  def sanitize_sort(sort) do
     sort
     |> List.wrap()
     |> Enum.map(fn