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doc-exports/docs/dws/tool/dws_16_0182.html
luhuayi a5e3903f6b DWS TG 910.211 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: luhuayi <luhuayi@huawei.com>
Co-committed-by: luhuayi <luhuayi@huawei.com>
2025-04-23 13:53:01 +00:00

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<a name="EN-US_TOPIC_0000001860199045"></a><a name="EN-US_TOPIC_0000001860199045"></a>
<h1 class="topictitle1">GROUP BY Conversion</h1>
<div id="body8662426"><p id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_p13755101311585">During MySQL/ADB group query, non-group columns can be queried. During GaussDB(DWS) group query, only group columns and aggregate functions can be queried, and if non-group columns are queried, an error will be reported. Therefore, GROUP BY in GaussDB(DWS) is changed to allow querying on non-group columns.</p>
<p id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_p2755131310587"><strong id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_b9271136761">Input</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_screen249911610616"><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">e</span><span class="p">.</span><span class="n">department_id</span><span class="p">,</span><span class="w"> </span><span class="n">department_name</span><span class="p">,</span><span class="w"> </span><span class="n">ROUND</span><span class="p">(</span><span class="k">AVG</span><span class="p">(</span><span class="n">salary</span><span class="p">),</span><span class="w"> </span><span class="mi">0</span><span class="p">)</span><span class="w"> </span><span class="n">avg_salary</span><span class="w"> </span><span class="k">FROM</span><span class="w"> </span><span class="n">employees</span><span class="w"> </span><span class="n">e</span><span class="w"> </span><span class="k">JOIN</span><span class="w"> </span><span class="n">departments</span><span class="w"> </span><span class="n">d</span><span class="w"> </span><span class="k">on</span><span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="n">department_id</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">d</span><span class="p">.</span><span class="n">department_id</span><span class="w"> </span><span class="k">GROUP</span><span class="w"> </span><span class="k">BY</span><span class="w"> </span><span class="n">department_name</span><span class="w"> </span><span class="k">ORDER</span><span class="w"> </span><span class="k">BY</span><span class="w"> </span><span class="n">department_name</span><span class="p">;</span>
</pre></div></td></tr></table></div>
</div>
<p id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_p1755013185819"><strong id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_b175848401566">Output</strong></p>
<div class="codecoloring" codetype="Sql" id="EN-US_TOPIC_0000001860199045__en-us_topic_0000001442160981_screen542018441166"><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">e</span><span class="p">.</span><span class="n">department_id</span><span class="p">,</span>
<span class="w"> </span><span class="n">department_name</span><span class="p">,</span>
<span class="w"> </span><span class="n">ROUND</span><span class="w"> </span><span class="p">(</span><span class="k">AVG</span><span class="p">(</span><span class="n">salary</span><span class="p">),</span><span class="w"> </span><span class="mi">0</span><span class="p">)</span><span class="w"> </span><span class="k">AS</span><span class="w"> </span><span class="ss">&quot;avg_salary&quot;</span>
<span class="k">FROM</span>
<span class="w"> </span><span class="n">employees</span><span class="w"> </span><span class="ss">&quot;e&quot;</span>
<span class="w"> </span><span class="k">JOIN</span><span class="w"> </span><span class="n">departments</span><span class="w"> </span><span class="ss">&quot;d&quot;</span><span class="w"> </span><span class="k">ON</span><span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="n">department_id</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">d</span><span class="p">.</span><span class="n">department_id</span>
<span class="k">GROUP</span><span class="w"> </span><span class="k">BY</span>
<span class="w"> </span><span class="n">department_name</span><span class="p">,</span>
<span class="w"> </span><span class="mi">1</span>
<span class="k">ORDER</span><span class="w"> </span><span class="k">BY</span>
<span class="w"> </span><span class="n">department_name</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_0177.html">Data Manipulation Language (DML)</a></div>
</div>
</div>
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