CREATE TABLE staff (staff_id VARCHAR, staff_first_name VARCHAR)
CREATE TABLE problems (problem_description VARCHAR, reported_by_staff_id VARCHAR)

Give me a list of descriptions of the problems that are reported by the staff whose first name is Christop.
SELECT T1.problem_description FROM problems AS T1 JOIN staff AS T2 ON T1.reported_by_staff_id = T2.staff_id WHERE T2.staff_first_name = "Christop"
SELECT "T1"."problem_description" FROM "problems" AS "T1" JOIN "staff" AS "T2" ON "Christop" = "T2"."staff_first_name" AND "T1"."reported_by_staff_id" = "T2"."staff_id"