1.Question 1
Why is it important to have extensive error checking on SQL statements when an application is in production?

ANS:	All of the above


2.Question 2
What is the purpose of the PDO::errorinfo() data?

ANS:	It gives extended detail when a PDO function returns an error


3.Question 3
How is a LEFT JOIN different from a regular JOIN?

ANS:	In a LEFT JOIN rows are included from the left table even if there is no matching row in the right table


4.Question 4
What is a common use of GROUP BY in SQL?

ANS:	When combined with the COUNT function, it provides a way to compute sub\-totals


5.Question 5
Why do subqueries have the potential to cause a query to execute slowly?

ANS:	Because MySQL executes the subquery independently from the main query

