CHAPTER 16

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Rewriting Queries

At the beginning of Chapter 1 I explained the naiveté of assuming that the CBO will come up with an optimal execution plan regardless of how you write your SQL statement. So far in this book you have already seen numerous cases where an improperly constructed SQL statement can cause the CBO to pick an inappropriate execution plan, there being quite a few examples in the last chapter alone. This chapter and the next explore the topic of rewriting SQL statements in more detail, but I won’t pretend to be giving you a full list of problematic scenarios.

In fact, this chapter is a lot shorter than it would have needed ...

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