102 lines
6.3 KiB
HTML
102 lines
6.3 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html lang="en-us" xml:lang="en-us">
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<head>
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<meta name="DC.Title" content="Example: Correlated subquery in select-list" />
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<meta name="abstract" content="Suppose that you want a list of all of the departments, including the department name, number, and manager's name." />
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<meta name="description" content="Suppose that you want a list of all of the departments, including the department name, number, and manager's name." />
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<meta name="DC.subject" content="correlation, subqueries, example select list, subquery, correlated, example select list, examples, correlated subquery, select list" />
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<meta name="keywords" content="correlation, subqueries, example select list, subquery, correlated, example select list, examples, correlated subquery, select list" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1998, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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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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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Example: Correlated subquery in select-list</title>
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</head>
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<body id="rbafyexsub3"><a name="rbafyexsub3"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">Example: Correlated subquery in select-list</h1>
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<div><p>Suppose that you want a list of all of the departments, including
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the department name, number, and manager's name.</p>
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<div class="section"><p>Department names and numbers are found in the CORPDATA.DEPARTMENT
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table. However, DEPARTMENT only has the manager's number, not the manager's
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name. To find the name of the manager for each department, you need to find
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the employee number from the EMPLOYEE table that matches the manager number
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in the DEPARTMENT table and return the name for the row that matches. Only
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departments that currently have a manager assigned are to be returned. Execute
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the following:</p>
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<pre><strong>SELECT</strong> DEPTNO, DEPTNAME,
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(<strong>SELECT</strong> FIRSTNME <strong>CONCAT</strong> ' ' <strong>CONCAT</strong>
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MIDINIT <strong>CONCAT</strong> ' ' <strong>CONCAT</strong> LASTNAME
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<strong>FROM</strong> EMPLOYEE X
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<strong>WHERE</strong> X.EMPNO = Y.MGRNO) AS MANAGER_NAME
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<strong>FROM</strong> DEPARTMENT Y
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<strong>WHERE</strong> MGRNO <strong>IS NOT NULL</strong></pre>
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<p>For each row returned
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for DEPTNO and DEPTNAME, the system finds where EMPNO = MGRNO and returns
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the manager's name. The result table produced by the query has the following
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values:</p>
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<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><caption>Table 1. Result set for previous query</caption><thead align="left"><tr><th valign="top" width="33.793103448275865%" id="d0e78">DEPTNO</th>
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<th valign="top" width="33.793103448275865%" id="d0e80">DEPTNAME</th>
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<th valign="top" width="32.41379310344827%" id="d0e82">MANAGER_NAME</th>
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</tr>
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</thead>
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<tbody><tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">A00</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">SPIFFY COMPUTER SERVICE DIV.</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">CHRISTINE I HAAS</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">B01</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">PLANNING</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">MICHAEL L THOMPSON</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">C01</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">INFORMATION CENTER</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">SALLY A KWAN</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">D11</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">MANUFACTURING SYSTEMS</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">IRVING F STERN</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">D21</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">ADMINISTRATION SYSTEMS</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">EVA D PULASKI</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">E01</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">SUPPORT SERVICES </td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">JOHN B GEYER</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">E11</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">OPERATIONS </td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">EILEEN W HENDERSON</td>
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</tr>
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<tr><td valign="top" width="33.793103448275865%" headers="d0e78 ">E21</td>
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<td valign="top" width="33.793103448275865%" headers="d0e80 ">SOFTWARE SUPPORT</td>
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<td valign="top" width="32.41379310344827%" headers="d0e82 ">THEODORE Q SPENSER</td>
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</tr>
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</tbody>
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</table>
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</div>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbafycorrs.htm" title="You can write a subquery that SQL might need to re-evaluate as it examines each new row (WHERE clause) or group of rows (HAVING clause) in the outer-level SELECT. This is called a correlated subquery.">Correlated subqueries</a></div>
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</div>
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</div>
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</body>
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</html>
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