[AdrianB1]

Remembering which join does what is easy: inner joins strictly joins the tables, left takes all on left (first table), right takes all on right (second table), outer (or cross) join are so rarely used you don't need to memorize.

[Semaphor]

> outer (or cross) join are so rarely used you don't need to memorize.

I’d say they are more important to know than right joins.