148 lines
7.6 KiB
HTML
148 lines
7.6 KiB
HTML
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<?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="logical operator, truth valued logic, description,
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search condition, truth table, AND, OR, order of evaluation" />
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<title>Search conditions</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="ch2srch"></a>
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<h2 id="ch2srch"><a href="rbafzmst02.htm#ToC_311">Search conditions</a></h2>
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<a href="rbafzmstch2srch.htm#synsearchcon"><img src="c.gif" alt="Click to skip syntax diagram" /></a>
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<a name="wq443"></a>
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<div class="fignone" id="wq443">
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<pre class="cgraphic"><span><img src="c.gif" alt="Read syntax diagram" longdesc="rbafzmstsyn37.htm"
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border="0" /></span><a href="#skipsyn-36"><img src="c.gif" alt="Skip visual syntax diagram"
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border="0" /></a>>>-+-----+--+-<span class="italic">predicate</span>----------+------------------------------>
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'-NOT-' '-<span class="italic">(search-condition)</span>-'
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.----------------------------------------------.
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V |
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>----+------------------------------------------+-+------------><
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'-+-AND-+--+-----+--+-<span class="italic">predicate</span>----------+-'
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'-OR--' '-NOT-' '-<span class="italic">(search-condition)</span>-'
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</pre>
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<a name="skipsyn-36" id="skipsyn-36"></a></div>
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<a name="synsearchcon"></a>
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<p id="synsearchcon">A <span class="italic">search condition</span> specifies
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a condition that is true, false, or unknown about a given row or group.</p><a id="idx779" name="idx779"></a><a id="idx780" name="idx780"></a><a id="idx781" name="idx781"></a>
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<p>The result of a search condition is derived by application of the specified <span class="italic">logical operators</span> (AND, OR, NOT) to the result of each
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specified predicate. If logical operators are not specified, the result of
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the search condition is the result of the specified predicate.</p><a id="idx782" name="idx782"></a><a id="idx783" name="idx783"></a><a id="idx784" name="idx784"></a>
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<p>AND and OR are defined in the following table in which P and Q are any
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predicates:</p>
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<a name="truth1"></a>
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<table id="truth1" width="100%" summary="" border="1" frame="hsides" rules="all">
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<caption>Table 27. Truth Tables for AND and OR</caption>
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<thead valign="bottom">
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<tr>
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<th id="wq444" width="25%" align="left" valign="bottom">P</th>
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<th id="wq445" width="25%" align="left" valign="bottom">Q</th>
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<th id="wq446" width="25%" align="left" valign="bottom">P AND Q</th>
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<th id="wq447" width="25%" align="left" valign="bottom">P OR Q</th>
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</tr>
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</thead>
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<tbody valign="top">
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<tr>
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<td align="left" valign="top" headers="wq444">
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<a id="booly" name="booly"></a>True</td>
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<td align="left" valign="top" headers="wq445">True</td>
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<td align="left" valign="top" headers="wq446">True</td>
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<td align="left" valign="top" headers="wq447">True</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">True</td>
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<td align="left" valign="top" headers="wq445">False</td>
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<td align="left" valign="top" headers="wq446">False</td>
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<td align="left" valign="top" headers="wq447">True</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">True</td>
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<td align="left" valign="top" headers="wq445">Unknown</td>
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<td align="left" valign="top" headers="wq446">Unknown</td>
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<td align="left" valign="top" headers="wq447">True</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">False</td>
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<td align="left" valign="top" headers="wq445">True</td>
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<td align="left" valign="top" headers="wq446">False</td>
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<td align="left" valign="top" headers="wq447">True</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">False</td>
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<td align="left" valign="top" headers="wq445">False</td>
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<td align="left" valign="top" headers="wq446">False</td>
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<td align="left" valign="top" headers="wq447">False</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">False</td>
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<td align="left" valign="top" headers="wq445">Unknown</td>
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<td align="left" valign="top" headers="wq446">False</td>
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<td align="left" valign="top" headers="wq447">Unknown</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">Unknown</td>
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<td align="left" valign="top" headers="wq445">True</td>
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<td align="left" valign="top" headers="wq446">Unknown</td>
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<td align="left" valign="top" headers="wq447">True</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">Unknown</td>
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<td align="left" valign="top" headers="wq445">False</td>
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<td align="left" valign="top" headers="wq446">False</td>
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<td align="left" valign="top" headers="wq447">Unknown</td>
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</tr>
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<tr>
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<td align="left" valign="top" headers="wq444">Unknown</td>
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<td align="left" valign="top" headers="wq445">Unknown</td>
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<td align="left" valign="top" headers="wq446">Unknown</td>
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<td align="left" valign="top" headers="wq447">Unknown</td>
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</tr>
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</tbody>
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</table>
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<p>NOT(true) is false, NOT(false) is true, and NOT(unknown) is unknown.</p><a id="idx785" name="idx785"></a>
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<p>Search conditions within parentheses are evaluated first. If the order
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of evaluation is not specified by parentheses, NOT is applied before AND,
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and AND is applied before OR. The order in which operators at the same precedence
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level are evaluated is undefined to allow for optimization of search conditions.</p>
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<a name="wq448"></a>
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<h3 id="wq448"><a href="rbafzmst02.htm#ToC_312">Examples</a></h3>
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<p>In the examples, the numbers on the second line indicate the order in which
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the operators are evaluated.</p>
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<a name="wq449"></a>
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<h4 id="wq449">Example 1</h4>
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<pre class="xmp"> MAJPROJ = 'MA2100' <span class="bold">AND</span> DEPTNO = 'D11' <span class="bold">OR</span> DEPTNO = 'B03' <span class="bold">OR</span> DEPTNO = 'E11'
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<span class="bold">1 2 or 3 2 or 3</span> </pre>
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<a name="wq450"></a>
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<h4 id="wq450">Example 2</h4>
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<pre class="xmp">MAJPROJ = 'MA2100' <span class="bold">AND</span> (DEPTNO = 'D11' <span class="bold">OR</span> DEPTNO = 'B03') <span class="bold">OR</span> DEPTNO = 'E11'
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<span class="bold">2 1 3</span></pre>
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<pre class="xmp"></pre>
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<hr /><br />
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[ <a href="#Top_Of_Page">Top of Page</a> | <a href="rbafzmstch2pred.htm">Previous Page</a> | <a href="rbafzmstch2func.htm">Next Page</a> | <a href="rbafzmst02.htm#wq1">Contents</a> |
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<a href="rbafzmstindex.htm#index">Index</a> ]
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<a id="Bot_Of_Page" name="Bot_Of_Page"></a>
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</body>
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</html>
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