Outer Join An extension of the join operation that avoids loss of information. ■ Computes the join and then adds tuples form one relation that does not match tuples in the other relation to the result of the join. ■Uses null values. Three forms of outer join: ·left outer join ·right outer join ·full outer join Database System Concepts-7th Edition 4.13 ©Silberscha乜，Korth and SudarshanDatabase System Concepts - 7 4.13 ©Silberschatz, Korth and Sudarshan th Edition Outer Join ▪ An extension of the join operation that avoids loss of information. ▪ Computes the join and then adds tuples form one relation that does not match tuples in the other relation to the result of the join. ▪ Uses null values. ▪ Three forms of outer join: • left outer join • right outer join • full outer join