有没有办法动态定义查询字段？

Question

受到这个伟大答案的启发 () 我认为可能有一种方法可以执行类似于此查询的操作来动态操作这些字段：
u.date, u.title, u.text - u.date_pt, u.title_pt, u.text_pt - u.date_es, u.title_es, u.text_es -... 在此查询中：

    def search(query, search_term, locale) do
        language =
          case locale do
            "pt" ->
              "Portuguese"
            "es" ->
              "Spanish"
            "fr" ->
              "Spanish"
            "de" ->
              "German"
            _ ->
              "English"
          end
        f = if locale in ~w(en pt es fr de), do: :"u.date_#{locale}, u.title_#{locale}, u.text_#{locale}", else: :u.date, u.title, u.text # This is WRONG, just to illustrate what's intended
        (from u in query,
        where: fragment("(to_tsvector(?, unaccent(?)) || to_tsvector(?, unaccent(?)) || to_tsvector(coalesce(?, unaccent(?)))) @@ plainto_tsquery(?, unaccent(?))", 
                         ^language, u.date, ^language, u.title, ^language, u.text, ^language, ^search_term),
        order_by: fragment("ts_rank((to_tsvector(?, ?) || to_tsvector(?, ?) || to_tsvector(coalesce(?, ?))), plainto_tsquery(?, ?)) DESC", 
                        ^language, u.date, ^language, u.title, ^language, u.text, ^language, ^search_term))
        |> Repo.all()
      end

是吗？

Answer 1

是的，您可以在 Ecto 查询中为此使用 field/2。我会这样做：

suffix = if locale in ~w(pt es fr de), do: "_#{locale}", else: ""

然后，在查询中，而不是

u.date

做：

field(u, ^:"date#{suffix}")

同理，u.title变为field(u, ^:"title#{suffix}")，依此类推。

有没有办法动态定义查询字段？

Is there a way to dynamically define the query fields?

elixir

ecto