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OCA/OCP Oracle Database 11g All-in-One Exam Guide with CD-ROM : Exams 1Z0-051, 1Z0-052, 1Z0-053 by Bob Bryla, Roopesh Ramklass, John Watson

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CHAPTER 11Group Functions

Exam Objectives

In this chapter you will learn to

• 051.5.1 Identify the Available Group Functions

• 051.5.2 Describe the Use of Group Functions

• 051.5.3 Group Data by Using the GROUP BY Clause

• 051.5.4 Include or Exclude Grouped Rows by Using the HAVING Clause

Single-row functions, explored in Chapter 10, return a single value for each row in a set of results. Group or aggregate functions operate on multiple rows. They are used to count the number of rows or to find the average of specific column values in a dataset. Many statistical operations, such as calculating standard deviation, medians, and averages, depend on executing functions against grouped data and not just single rows.

You will examine group functions ...

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