Summary of SQL Join Syntax
1. Cross Join
the result is Cartesian product or simply product
e.g., Movie CROSS JOIN StarsIn
1. Theta Join
Product on some conditions
e.g., Movie JOIN StarsIn ON title = movieTitle AND year = movieYear
1. Natural Join
the condition in theta join is just all pairs of attributes with same name
one of each pair of same name is projected out
1. Outer Join
augment the result of a join by the dangling tuples, padded with null values
FULL OUTER JOIN
LEFT OUTER JOIN
RIGHT OUTER JOIN