title: Write a query to find the full names of customers who have rented sci-fi movies more than 5 times. Arrange these names in the alphabetical order
body: <p>Hello below is my Code</p>
  
  <p>DB: <a href="https://dev.mysql.com/doc/sakila/en/sakila-structure.html" rel="nofollow noreferrer">https://dev.mysql.com/doc/sakila/en/sakila-structure.html</a></p>
  
  <pre><code>select concat(first_name,' ',last_name) from
  customer where customer_id in (
  select customer_id from (
  select customer_id, count(rental_id) as num
  from 
  category 
  inner join film_category using(category_id) 
  inner join film using(film_id) 
  inner join inventory using(film_id) 
  inner join rental using (inventory_id)
  where name='Sci-Fi'
  group by customer_id, rental_id)
  where num &gt; 5)T)
  </code></pre>
  
  <p>when i am executing i am getting the below error</p>
  
  <pre><code>ERROR 1248 (42000) at line 2: Every derived table must have its own alias
  </code></pre>
  
  <p>Expected Outcome is <code>"full names of customers who have rented sci-fi movies more than 5 times. Arrange these names in the alphabetical order"</code></p>
  
  <p>Could you please let me know what is the mistake i am doing?</p>