September 2010
Intermediate to advanced
1704 pages
111h 8m
English
An outer join is used to return all the rows from the specified outer table (specified with LEFT OUTER, RIGHT OUTER, or FULL OUTER), even if the other table has no match. Rows returned from the outer table that have no corresponding match in the inner table display the value NULL for any columns retrieved from the inner table. For example, you might want to display the names of all authors along with the average royalty paid, if available:

Note that no real difference exists between left and right outer joins except for specifying which table on which side of the join condition is to be the controlling, or outer, table. ...