Something like

Enum.map(a.cms_post, &(Map.get(&1,:title)))

would return a list of title values

Map.get/3
Enum.map/2

a.cms_post
|> hd()
|> Map.get(:title)

returns the title of the post in the head of the list

Kernel.hd/1

def get_title([%TrangellCmsService.Cms.Db.Post{title: title}|_]),
  do: title

i.e. using pattern matching for destructuring rather than dot notation.

Not array, it is a linked list, and you can use the usual iteration functions from the Enum module.

You can not directly acces the fields because it’s ambiguous which of the potentially many lists contents you want to access.

@shahryarjb If I understand you correctly then this code should help you:

categories # here you have root list from your gist
|> Enum.find(& &1.seo_alias_link == "jsjsjs") # here you have list element
|> Map.fetch!(:cms_post) # here you are fetching sub-list from element
|> Enum.map(& &1.title) # finally here you are getting title for all elements

@shahryarjb: Sorry, but I don’t know few things:

1. What’s value of category_alias variable - "jsjsjs" ?
2. What’s value of group_acl variable - root list from gist ?
3. fetch_posts_by_category_alias function body

If I assumed correctly (about your variables) then:

def load_posts_by_category_alias(category_alias, group_acl) do
  group_acl
  |> Enum.find(& &1.seo_alias_link == category_alias)
  |> Map.fetch!(:cms_post)
  |> Enum.map(& &1.title)
end

@shahryarjb: Then it’s really simple. Assuming you want only list of titles:

defmodule Example do
  import Ecto.Query

  # aliases for Post and PostCategory here

  def sample(seo_alias_link, group_acl) do
    query =
      from(
        post_category in PostCategory,
        inner_join: post in assoc(post_category, :cms_post),
        order_by: post_category.inserted_at,
        limit: 10,
        select: post.title,
        where: p.seo_alias_link == ^seo_alias_link
      )

    if group_acl == "admin" do
      query
    else
      where(
        query,
        [post_category, post],
        post_category.group_acl == ^group_acl and post.group_acl == ^group_acl
      )
    end
  end
end

"jsjsjs" |> Example.sample("admin") |> Repo.all