While it is true on the schema level, it is not true at the query level. The most frequently used kind of join is a general relation. [1] https://github.com/a

While it is true on the schema level, it is not true at the query level. The most frequently used kind of join is a general relation. [1] https://github.com/agirish/tpcds/blob/master/query1.sql https://github.com/agirish/tpcds/blob/master/query1.sql Query 1 from TPC-DS creates a multi-column relation by using GROUP BY. Which relation is then partially constrained by different columns from different tables.