task Missing relationships / anti-joins · medium

Routes flown in one direction only

Return origin and destination for routes whose reverse (destination → origin) does not exist in routes.

what to return

Columns

origindestination in this order

Rows

46 rows · any order

Skill

Find relationships that are not symmetric. Refresher: Self-joins & referral relationships →

expected result

Your query should return exactly these columns and values. Run it and compare.

data you can query

U.S. Flights dataset: the first 6 rows of each table. Under each column name: the kind of value it holds, and which table it links to. Your queries run on all rows.