In order to test your progress, you should be able to answer the following questions.
A NULLIF function returns NULL if
_____ expression1 equals expression2.
_____ expression1 does not equal expression2.
A NULLIF function is just like NVL function.
You can specify literal NULL in the first expression of the NULLIF function.
A COALESCE function returns
_____ first null expression.
_____ first non-null expression.
_____ first expression only.
You can never specify literal NULL as one of the expressions in the COALESCE function.
Answers appear in Appendix A, Section 6.3 .