A suboptimal query

Exercise: What courses have been taken by both Bart and Lisa?

SELECT bart.course$\_$id

EROM grades bart

JOIN grades lisa ON lisa.course$\_$id $=$ bart.course$\_$id

WHERE bart.student id $=123$

AND lisa.student$\_$i $\frac{?}{\text{b}\text{a}\text{r}}(d)=888$;

problem: requires us to know Bart$/$Lisa$\text{'}$s Student IDs, and only spits back course IDs,

not names.

Write a version of this query that gets us the course names, and only requires us to

know Bart$/$Lisa$\text{'}$s names, not their IDs.