Understanding DB2®: Learning Visually with Examples

Chapter 9

A1:	A. The condition of having lastname starting with the letter P returns two rows. However, the result set is further reduced to one row to obtain the only record that has a salary greater than $38,500.
A2:	D. Unknown values are identified by NULL. You verify the nullability of a value by checking IS NULL. The values '' and "" are known values of empty strings.
A3:	C. Selecting from an UPDATE, DELETE, or INSERT statement is an SQL enhancement available in DB2 Version 8.1 FixPak 4 or later. If the statement is executed on DB2 Version 8.1 with an earlier FixPak, it will fail. With FixPak 4 or later, the statement will execute the DELETE statement and return the number of rows removed.
A4:	C. An INTERSECT operation retrieves the matching ...