109 lines
6.2 KiB
HTML
109 lines
6.2 KiB
HTML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
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"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-us">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="dc.language" scheme="rfc1766" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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<meta name="dc.date" scheme="iso8601" content="2005-09-19" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow"/>
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="keywords" content="IF statement, SQL-control-statement,
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SQL statements" />
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<title>IF statement</title>
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<link rel="stylesheet" type="text/css" href="ibmidwb.css" />
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<link rel="stylesheet" type="text/css" href="ic.css" />
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</head>
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<body>
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<a id="Top_Of_Page" name="Top_Of_Page"></a><!-- Java sync-link -->
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<script language = "Javascript" src = "../rzahg/synch.js" type="text/javascript"></script>
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<a name="ifstmt"></a>
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<h2 id="ifstmt"><a href="rbafzmst02.htm#ToC_1445">IF statement</a></h2><a id="idx3354" name="idx3354"></a><a id="idx3355" name="idx3355"></a>
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<p>The IF statement executes different sets of SQL statements based on the
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result of search conditions.</p>
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<a name="wq1884"></a>
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<h3 id="wq1884"><a href="rbafzmst02.htm#ToC_1446">Syntax</a></h3>
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<a href="rbafzmstifstmt.htm#syncif"><img src="c.gif" alt="Click to skip syntax diagram" /></a>
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<pre class="cgraphic"><span><img src="c.gif" alt="Read syntax diagram" longdesc="rbafzmstsyn417.htm"
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border="0" /></span><a href="#skipsyn-416"><img src="c.gif" alt="Skip visual syntax diagram"
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border="0" /></a>>>-+--------+--IF--<span class="italic">search-condition</span>--THEN----------------------->
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'-<span class="italic">label:</span>-'
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.-----------------------------.
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V |
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>----<span class="italic">SQL-procedure-statement</span>-- ;-+------------------------------>
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.---------------------------------------------------------------------.
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V |
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>----+-----------------------------------------------------------------+-+-->
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| .-----------------------------. |
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| V | |
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'-ELSEIF--<span class="italic">search-condition</span>--THEN----<span class="italic">SQL-procedure-statement</span>-- ;-+-'
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>--+---------------------------------------+--END IF-----------><
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| .-----------------------------. |
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| V | |
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'-ELSE----<span class="italic">SQL-procedure-statement</span>-- ;-+-'
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</pre>
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<a name="skipsyn-416" id="skipsyn-416"></a>
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<a name="syncif"></a>
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<h3 id="syncif"><a href="rbafzmst02.htm#ToC_1447">Description</a></h3>
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<dl class="parml">
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<dt class="bold"><span class="italic">label</span></dt>
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<dd>Specifies the label for the IF statement. The label name
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cannot be the same as another label within the same scope. For more information,
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see <a href="rbafzmstsqlprocstmt.htm#psscope">Labels</a>.
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</dd>
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<dt class="bold"><span class="italic">search-condition</span></dt>
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<dd>Specifies the <var class="pv">search-condition</var> for which an SQL statement should
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be executed. If the condition is unknown or false, processing continues to
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the next search condition, until either a condition is true or processing
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reaches the ELSE clause.
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</dd>
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<dt class="bold"><span class="italic">SQL-procedure-statement</span></dt>
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<dd>Specifies an SQL statement that should be executed if the preceding <span class="italic">search-condition</span> is true.
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</dd>
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</dl>
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<a name="wq1885"></a>
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<h3 id="wq1885"><a href="rbafzmst02.htm#ToC_1448">Example</a></h3>
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<p>The following SQL procedure accepts two IN parameters: an employee number
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and an employee rating. Depending on the value of <span class="italic">rating</span>, the employee table is updated with new values in the salary and bonus
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columns.</p>
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<pre class="xmp"><span class="bold">CREATE PROCEDURE</span> UPDATE_SALARY_IF
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<span class="bold">(IN</span> employee_number <span class="bold">CHAR</span>(6), <span class="bold">INOUT</span> rating <span class="bold">SMALLINT)</span>
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<span class="bold">LANGUAGE SQL</span>
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<span class="bold">MODIFIES SQL DATA</span>
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<span class="bold">BEGIN</span>
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<span class="bold">DECLARE</span> not_found <span class="bold">CONDITION FOR SQLSTATE</span> '02000';
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<span class="bold">DECLARE EXIT HANDLER FOR</span> not_found
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<span class="bold">SET</span> rating = -1;
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<span class="bold">IF</span> rating = 1
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<span class="bold">THEN UPDATE</span> employee
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<span class="bold">SET</span> salary = salary * 1.10, bonus = 1000
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<span class="bold">WHERE</span> empno = employee_number;
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<span class="bold">ELSEIF</span> rating = 2
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<span class="bold">THEN UPDATE</span> employee
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<span class="bold">SET</span> salary = salary * 1.05, bonus = 500
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<span class="bold">WHERE</span> empno = employee_number;
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<span class="bold">ELSE UPDATE</span> employee
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<span class="bold">SET</span> salary = salary * 1.03, bonus = 0
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<span class="bold">WHERE</span> empno = employee_number;
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<span class="bold">END IF</span>;
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<span class="bold">END</span> </pre>
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<hr /><br />
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