exp_021.htm

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<p><b><span style="font-size:22pt">Explaination 021: &nbsp;</span></b></p>

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	<p>
	The operator in the WHERE clause should be changed to display the desired results. There are times when you want to substitute a value in place of NULL. Oracle provides this functionality with a special function, called NVL(). You cannot use operation equal with NULL, but you can achieve desired results using NVL() function after the WHERE clause. <br>
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	<p>
	  Incorrect Answers <br>
	</p>

	<p>
	  A: The SQL statement will generate an error because you cannot use operation equal with NULL. <br>
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	  B: The column in the WHERE clause should not be changed to display the desired results. <br>
	</p>

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	  D: Since there is only one table used in this query you don't need to use outer join to display the desired results. <br>
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	<p>
	  OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 31-32 <br>
	</p>

	<p>
	  Chapter 1: Overview of Oracle Databases
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