95 lines
5.7 KiB
HTML
95 lines
5.7 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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<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="keywords" content="LOOP statement, SQL-control-statement,
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SQL statements" />
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<title>LOOP statement</title>
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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="loopstmt"></a>
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<h2 id="loopstmt"><a href="rbafzmst02.htm#ToC_1458">LOOP statement</a></h2><a id="idx3360" name="idx3360"></a><a id="idx3361" name="idx3361"></a>
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<p>The LOOP statement repeats the execution of a statement or a group of statements.</p>
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<a name="wq1891"></a>
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<h3 id="wq1891"><a href="rbafzmst02.htm#ToC_1459">Syntax</a></h3>
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<a href="rbafzmstloopstmt.htm#syncloop"><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="rbafzmstsyn420.htm"
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border="0" /></span><a href="#skipsyn-419"><img src="c.gif" alt="Skip visual syntax diagram"
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border="0" /></a> .-----------------------------.
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V |
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>>-+--------+--LOOP----<span class="italic">SQL-procedure-statement</span>-- ;-+------------>
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'-<span class="italic">label:</span>-'
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>--END LOOP--+-------+-----------------------------------------><
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'-<span class="italic">label</span>-'
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</pre>
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<a name="skipsyn-419" id="skipsyn-419"></a>
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<a name="syncloop"></a>
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<h3 id="syncloop"><a href="rbafzmst02.htm#ToC_1460">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 LOOP statement. If the ending
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label is specified, it must be the same as the beginning label. The label
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name 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">SQL-procedure statement</span></dt>
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<dd>Specifies an SQL statement to be executed in the loop
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</dd>
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</dl>
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<a name="wq1892"></a>
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<h3 id="wq1892"><a href="rbafzmst02.htm#ToC_1461">Examples</a></h3>
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<p>This procedure uses a LOOP statement to fetch values from the employee
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table. Each time the loop iterates, the OUT parameter <span class="italic">counter</span> is incremented and the value of <span class="italic">v_midinit</span> is checked to ensure that the value is not a single space (' '). If <span class="italic">v_midinit</span> is a single space, the LEAVE statement passes
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the flow of control outside of the loop.</p>
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<pre class="xmp"> <span class="bold">CREATE PROCEDURE</span> LOOP_UNTIL_SPACE <span class="bold">(OUT</span> COUNTER <span class="bold">INTEGER)</span>
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<span class="bold">LANGUAGE SQL</span>
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<span class="bold">BEGIN</span>
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<span class="bold">DECLARE</span> v_counter <span class="bold">INTEGER DEFAULT </span>0;
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<span class="bold">DECLARE</span> v_firstnme <span class="bold">VARCHAR(</span>12<span class="bold">)</span>;
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<span class="bold">DECLARE</span> v_midinit <span class="bold">CHAR(</span>1<span class="bold">)</span>;
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<span class="bold">DECLARE</span> v_lastname <span class="bold">VARCHAR(</span>15<span class="bold">)</span>;
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<span class="bold">DECLARE</span> c1 <span class="bold">CURSOR FOR</span>
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<span class="bold">SELECT</span> firstnme, midinit, lastname
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<span class="bold">FROM</span> employee;
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<span class="bold">DECLARE CONTINUE HANDLER FOR NOT FOUND</span>
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<span class="bold">SET</span> counter = -1;
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<span class="bold">OPEN</span> c1;
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fetch_loop:
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<span class="bold">LOOP</span>
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<span class="bold">FETCH</span> c1 <span class="bold">INTO</span> v_firstnme, v_midinit, v_lastname;
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<span class="bold">IF</span> v_midinit = ' ' <span class="bold">THEN</span>
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<span class="bold">LEAVE</span> fetch_loop;
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<span class="bold">END IF</span>;
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<span class="bold">SET</span> v_counter = v_counter + 1;
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<span class="bold">END LOOP</span> fetch_loop;
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<span class="bold">SET</span> counter = v_counter;
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<span class="bold">CLOSE</span> c1;
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<span class="bold">END</span></pre>
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