How to write if condition in middle of Ecto query

thank you , unfortunately, I didn’t understand. may you edit my code ?

post = Repo.all from p in PostCategory,
           join: c in assoc(p, :cms_post),
	   where: p.id == ^category_id,
	   if group_acl != "admin" do
	      where: p.group_acl == ^group_acl,
  	      where: c.group_acl == ^group_acl,
	   end
	   order_by: p.inserted_at,
	   limit: 10,
           preload: [cms_post: c]

I just need to edit 2 lines which is below; can I do condition without creation again?

where: p.group_acl == ^group_acl,
where: c.group_acl == ^group_acl,

https://hexdocs.pm/ecto/Ecto.Query.html#select_merge/3

I’m seeing something what is the whole of all code will be edited by me, not part of it.