How to delete/drop table?

drop table("posts")

drop index("posts", [:title])
drop index("posts", [:slug])

As a minor note, dropping the indexes is unnecessary, they will be removed when the table they are built for is deleted.

can I know where I should write this? does this work from terminal?

You’ll need to make a new migration file with a different name, and you can use the same format as you posted in the OP. Then run it with mix ecto.migrate

More details at Ecto.Migration

No, you have to create a new migration, I named it DropPosts here but you can use any name you like.

To generate migration type the following command in terminal. More about it here mix ecto.gen.migration — Ecto SQL v3.14.0

mix ecto.gen.migration drop_posts

And then add change function to the migration file

defmodule Blogs.Repo.Migrations.DropPosts do
  use Ecto.Migration

  def change do
    drop table("posts")
  end
end

Thanks, that helped!