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<p><b><span style="font-size:22pt">Explaination 008: &nbsp;</span></b></p>

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	<p>
	This SELECT statement provides correct usage of NVL function to calculate columns for all employees. Oracle give you possibility to substitute a value in place of NULL. The basic syntax for NVL() is NVL(column_name, value_if_null). Notice that the column specified in NVL() contains an actual value. That value is what Oracle returns; when the column is NULL, the special string is returned. The value specified to be returned if the column value is NULL must be the same datatype as the column specified. <br>
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	<p>
	  Incorrect Answers <br>
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	<p>
	  A: This SELECT statement will return NULL value for rows with NULL COMMISION_PCT column. <br>
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	  B: It is incorrect syntax in this query: NVL function needs to be used for orrect result. <br>
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	  D: The DECODE function is used as substitution of IF-THEN-ELSE PL/SQL construction in SQL queries. The SELECT statement provides incorrect syntax of it cannot have only twoparameters. <br>
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	<p>
	  OCP Introduction to Oracle 9i: SQL Exam Guide, Jason Couchman, p. 31-32 <br>
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	<p>
	  Chapter 1: Overview of Oracle Databases
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