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Lu, Huayi 27019c2991 DWS TOOL 830.201 version 
Reviewed-by: Hasko, Vladimir <vladimir.hasko@t-systems.com>
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2024-05-16 07:35:25 +00:00

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<a name="EN-US_TOPIC_0000001819416133"></a><a name="EN-US_TOPIC_0000001819416133"></a>
<h1 class="topictitle1">ALIAS</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p57348914111332"><strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b10818131473211">ALIAS</strong> is supported by all databases. In Teradata, an <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b21186365363211">ALIAS</strong> can be referred in <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b10700419203211">SELECT</strong> and <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b11207617033211">WHERE</strong> clauses of the same statement where the alias is defined. Since <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b14004154693211">ALIAS</strong> is not supported in <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b7297204223211">SELECT</strong> and <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b15050526503211">WHERE</strong> clauses in the target, it is replaced by the defined value/expression.</p>
<div class="note" id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_note16489131915345"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p1664062815533">The comparison operators LT, LE, GT, GE, EQ, and NE must not be used as TABLE alias or COLUMN alias.</p>
<p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p3613187185411">The tool supports column ALIAS. If the ALIAS is the same as the column name, the ALIAS is specified only for that column and not for other columns in the table. In the following example, the column name <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b5151711102417">DATA_DT</strong> conflicts with the alias <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b189972032413">DATA_DT</strong>, which is not supported by the tool.</p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_screen653125513455"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span><span class="w"> </span><span class="n">DATA_DT</span><span class="p">,</span><span class="n">DATA_INT</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">DATA_DT</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">KK</span><span class="w"> </span><span class="k">WHERE</span><span class="w"> </span><span class="n">DATA_DT</span><span class="o">=</span><span class="nb">DATE</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</div></div>
<p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p12109175818553"><strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b2017182015617">Input: ALIAS</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_screen3716113110612"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
<span class="normal"> 2</span>
<span class="normal"> 3</span>
<span class="normal"> 4</span>
<span class="normal"> 5</span>
<span class="normal"> 6</span>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal">10</span>
<span class="normal">11</span>
<span class="normal">12</span>
<span class="normal">13</span>
<span class="normal">14</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span>
<span class="w"> </span><span class="n">expression1</span><span class="w"> </span><span class="p">(</span>
<span class="w"> </span><span class="n">TITLE</span><span class="w"> </span><span class="s1">'Expression 1'</span>
<span class="w"> </span><span class="p">)</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias1</span>
<span class="w"> </span><span class="p">,</span><span class="k">CASE</span>
<span class="w"> </span><span class="k">WHEN</span><span class="w"> </span><span class="n">alias1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">Cx</span><span class="w"> </span><span class="o">&gt;=</span><span class="w"> </span><span class="n">z</span>
<span class="w"> </span><span class="k">THEN</span><span class="w"> </span><span class="mi">1</span>
<span class="w"> </span><span class="k">ELSE</span><span class="w"> </span><span class="mi">0</span>
<span class="w"> </span><span class="k">END</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias2</span>
<span class="w"> </span><span class="k">FROM</span>
<span class="w"> </span><span class="n">tab1</span>
<span class="w"> </span><span class="k">WHERE</span>
<span class="w"> </span><span class="n">alias1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">y</span>
<span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p1771893118615"><strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b11211260123211">Output:</strong> <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b9696315543211">tdMigrateALIAS = FALSE</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_screen1359031822415"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
<span class="normal"> 2</span>
<span class="normal"> 3</span>
<span class="normal"> 4</span>
<span class="normal"> 5</span>
<span class="normal"> 6</span>
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<span class="normal"> 9</span>
<span class="normal">10</span>
<span class="normal">11</span>
<span class="normal">12</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span>
<span class="w"> </span><span class="n">expression1</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias1</span>
<span class="w"> </span><span class="p">,</span><span class="k">CASE</span>
<span class="w"> </span><span class="k">WHEN</span><span class="w"> </span><span class="n">alias1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">Cx</span><span class="w"> </span><span class="o">&gt;=</span><span class="w"> </span><span class="n">z</span>
<span class="w"> </span><span class="k">THEN</span><span class="w"> </span><span class="mi">1</span>
<span class="w"> </span><span class="k">ELSE</span><span class="w"> </span><span class="mi">0</span>
<span class="w"> </span><span class="k">END</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias2</span>
<span class="w"> </span><span class="k">FROM</span>
<span class="w"> </span><span class="n">tab1</span>
<span class="w"> </span><span class="k">WHERE</span>
<span class="w"> </span><span class="n">alias1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">y</span>
<span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_p67371651192515"><strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b3899334933211">Output:</strong> <strong id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_b3674480643211">tdMigrateALIAS = TRUE</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001819416133__en-us_topic_0000001658024494_en-us_topic_0000001434910241_screen1373725192517"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
<span class="normal"> 2</span>
<span class="normal"> 3</span>
<span class="normal"> 4</span>
<span class="normal"> 5</span>
<span class="normal"> 6</span>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal">10</span>
<span class="normal">11</span>
<span class="normal">12</span></pre></div></td><td class="code"><div><pre><span></span><span class="k">SELECT</span>
<span class="w"> </span><span class="n">expression1</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias1</span>
<span class="w"> </span><span class="p">,</span><span class="k">CASE</span>
<span class="w"> </span><span class="k">WHEN</span><span class="w"> </span><span class="n">expression1</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">Cx</span><span class="w"> </span><span class="o">&gt;=</span><span class="w"> </span><span class="n">z</span>
<span class="w"> </span><span class="k">THEN</span><span class="w"> </span><span class="mi">1</span>
<span class="w"> </span><span class="k">ELSE</span><span class="w"> </span><span class="mi">0</span>
<span class="w"> </span><span class="k">END</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="n">alias2</span>
<span class="w"> </span><span class="k">FROM</span>
<span class="w"> </span><span class="n">tab1</span>
<span class="w"> </span><span class="k">WHERE</span>
<span class="w"> </span><span class="n">expression1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">y</span>
<span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_16_0049.html">Query Migration Operators</a></div>
</div>
</div>
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