SQLJoin

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

• default is LEFT INNER JOIN

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

• e.g., MovieStar NATURAL JOIN MovieExec

1. Outer Join

• augment the result of a join by the dangling tuples, padded with null values

• e.g., MovieStar NATURAL FULL OUTER JOIN MovieExec

1. FULL OUTER JOIN

2. LEFT OUTER JOIN

3. RIGHT OUTER JOIN

1. References

• http://en.wikipedia.org/wiki/Join_(SQL)