SQL join query and SQLjoin connection

SQL join query and SQLjoin connection
 Inner join (Intersection,Natural connection, Abbreviated as join)Is the most common connection query, which is equivalent to the query based on the where condition in the early stage.Outer join (Union or partial union, left table + right table) 

• Left [outer] join (the left table generates a full set. If the right table has a match, if not, it is null)

• Right [outer] join (the right table generates a full set. If there is a left table, it matches, and if not, it is null)

• Full [outer] join (union)

Cross join (Cartesian Product, left table * right table)Not required in development