Good job! Now, it's time to review what we learned in this part. There are multiple ways you can invoke one function inside another:

• By using the SELECT INTO syntax:

  SELECT thumbs_down, thumbs_up
  INTO downvotes, upvotes
  FROM get_post_score(17);
  

• By using a function in assignment:

  user_id := get_most_active_user();

• If you want to omit the result returned by the function, use PERFORM:

  PERFORM remove_user_account(101);

If the function is not supposed to return a value, specify void as its return type.

Using functions, you can also return tables or sets with the following commands:

• RETURNS TABLE along with RETURN QUERY or RETURN NEXT.
• RETURNS SETOF along with RETURN QUERY or RETURN NEXT.