List the lessons taken by each customer first and last name.
select t2.first_name, t2.last_name, count(*) from lessons as t1 join customers as t2 on t1.customer_id = t2.customer_id group by t2.customer_id
Just show that information for the completed status lessons.
select t2.first_name, t2.last_name, count(*) from lessons as t1 join customers as t2 on t1.customer_id = t2.customer_id group by t2.customer_id where t1.lesson_status_code = 'Completed'
How many lessons taken by customer with first name as Rylan and last name as Goodwin were completed?
select count(*) from lessons as t1 join customers as t2 on t1.customer_id = t2.customer_id where t2.first_name = "Rylan" and t2.last_name = "Goodwin" and t1.lesson_status_code = "Completed";