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Trend<!----></a><ul class="vp-sidebar-sub-headers"></ul><!--]--></li><li><!--[--><a class="vp-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Operators-Functions/Sample.html"><!---->Sample<!----></a><ul class="vp-sidebar-sub-headers"></ul><!--]--></li><li><!--[--><a class="vp-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Operators-Functions/Time-Series.html"><!---->Time-Series<!----></a><ul class="vp-sidebar-sub-headers"></ul><!--]--></li><li><!--[--><a class="vp-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Operators-Functions/Lambda.html"><!---->Lambda<!----></a><ul class="vp-sidebar-sub-headers"></ul><!--]--></li><li><!--[--><a class="vp-link nav-link vp-sidebar-link vp-sidebar-page" href="/UserGuide/V1.0.x/Operators-Functions/Data-Profiling.html"><!---->Data Profiling<!----></a><ul class="vp-sidebar-sub-headers"></ul><!--]--></li><li><!--[--><a class="vp-link nav-link vp-sidebar-link vp-sidebar-page" 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10.874 7.637 13.592 4.143 194.44 97.22 354.963 220.201 392.763-122.204 37.542-214.893 196.511-220.2 389.397-4.661 5.049-7.638 11.651-7.638 19.03v5.825h566.49v-5.825c0-7.379-2.849-13.981-7.509-18.9-5.049-193.016-97.867-351.985-220.2-389.527 123.24-37.67 216.446-198.453 220.588-392.892zM531.16 450.445v352.632c117.674 1.553 211.787 40.778 211.787 88.676H304.097c0-48.286 95.149-87.382 213.728-88.676V450.445c-93.077-3.107-167.901-81.297-167.901-177.093 0-8.803 6.99-15.793 15.793-15.793 8.803 0 15.794 6.99 15.794 15.793 0 80.261 63.69 145.635 142.01 145.635s142.011-65.374 142.011-145.635c0-8.803 6.99-15.793 15.794-15.793s15.793 6.99 15.793 15.793c0 95.019-73.789 172.82-165.96 177.093z"></path></svg><span>About 1 min</span><meta property="timeRequired" content="PT1M"></span><!----><!----></div><hr></div><!----><!----><div class="theme-hope-content"><!--

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--><h1 id="constant-timeseries-generating-functions" tabindex="-1"><a class="header-anchor" href="#constant-timeseries-generating-functions" aria-hidden="true">#</a> Constant Timeseries Generating Functions</h1><p>The constant timeseries generating function is used to generate a timeseries in which the values of all data points are the same.</p><p>The constant timeseries generating function accepts one or more timeseries inputs, and the timestamp set of the output data points is the union of the timestamp sets of the input timeseries.</p><p>Currently, IoTDB supports the following constant timeseries generating functions:</p><table><thead><tr><th>Function Name</th><th>Required Attributes</th><th>Output Series Data Type</th><th>Description</th></tr></thead><tbody><tr><td>CONST</td><td><code>value</code>: the value of the output data point <br><code>type</code>: the type of the output data point, it can only be INT32 / INT64 / FLOAT / DOUBLE / BOOLEAN / TEXT</td><td>Determined by the required attribute <code>type</code></td><td>Output the user-specified constant timeseries according to the attributes <code>value</code> and <code>type</code>.</td></tr><tr><td>PI</td><td>None</td><td>DOUBLE</td><td>Data point value: a <code>double</code> value of <code>π</code>, the ratio of the circumference of a circle to its diameter, which is equals to <code>Math.PI</code> in the <em>Java Standard Library</em>.</td></tr><tr><td>E</td><td>None</td><td>DOUBLE</td><td>Data point value: a <code>double</code> value of <code>e</code>, the base of the natural logarithms, which is equals to <code>Math.E</code> in the <em>Java Standard Library</em>.</td></tr></tbody></table><p>Example:</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token keyword">select</span> s1<span class="token punctuation">,</span> s2<span class="token punctuation">,</span> const<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> <span class="token string">&#39;value&#39;</span><span class="token operator">=</span><span class="token string">&#39;1024&#39;</span><span class="token punctuation">,</span> <span class="token string">&#39;type&#39;</span><span class="token operator">=</span><span class="token string">&#39;INT64&#39;</span><span class="token punctuation">)</span><span class="token punctuation">,</span> pi<span class="token punctuation">(</span>s2<span class="token punctuation">)</span><span class="token punctuation">,</span> e<span class="token punctuation">(</span>s1<span class="token punctuation">,</span> s2<span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">;</span> 
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Result:</p><div class="language-text line-numbers-mode" data-ext="text"><pre class="language-text"><code>select s1, s2, const(s1, &#39;value&#39;=&#39;1024&#39;, &#39;type&#39;=&#39;INT64&#39;), pi(s2), e(s1, s2) from root.sg1.d1; 
+-----------------------------+--------------+--------------+-----------------------------------------------------+------------------+---------------------------------+
|                         Time|root.sg1.d1.s1|root.sg1.d1.s2|const(root.sg1.d1.s1, &quot;value&quot;=&quot;1024&quot;, &quot;type&quot;=&quot;INT64&quot;)|pi(root.sg1.d1.s2)|e(root.sg1.d1.s1, root.sg1.d1.s2)|
+-----------------------------+--------------+--------------+-----------------------------------------------------+------------------+---------------------------------+
|1970-01-01T08:00:00.000+08:00|           0.0|           0.0|                                                 1024| 3.141592653589793|                2.718281828459045|
|1970-01-01T08:00:00.001+08:00|           1.0|          null|                                                 1024|              null|                2.718281828459045|
|1970-01-01T08:00:00.002+08:00|           2.0|          null|                                                 1024|              null|                2.718281828459045|
|1970-01-01T08:00:00.003+08:00|          null|           3.0|                                                 null| 3.141592653589793|                2.718281828459045|
|1970-01-01T08:00:00.004+08:00|          null|           4.0|                                                 null| 3.141592653589793|                2.718281828459045|
+-----------------------------+--------------+--------------+-----------------------------------------------------+------------------+---------------------------------+
Total line number = 5
It costs 0.005s
</code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></div><!----><footer class="page-meta"><div class="meta-item edit-link"><a href="https://github.com/apache/iotdb-docs/edit/main/src/UserGuide/V1.0.x/Operators-Functions/Constant.md" rel="noopener noreferrer" target="_blank" aria-label="Found Error? Edit this page on GitHub" class="nav-link label"><!--[--><svg xmlns="http://www.w3.org/2000/svg" class="icon edit-icon" viewBox="0 0 1024 1024" fill="currentColor" aria-label="edit icon"><path d="M430.818 653.65a60.46 60.46 0 0 1-50.96-93.281l71.69-114.012 7.773-10.365L816.038 80.138A60.46 60.46 0 0 1 859.225 62a60.46 60.46 0 0 1 43.186 18.138l43.186 43.186a60.46 60.46 0 0 1 0 86.373L588.879 565.55l-8.637 8.637-117.466 68.234a60.46 60.46 0 0 1-31.958 11.229z"></path><path d="M728.802 962H252.891A190.883 190.883 0 0 1 62.008 771.98V296.934a190.883 190.883 0 0 1 190.883-192.61h267.754a60.46 60.46 0 0 1 0 120.92H252.891a69.962 69.962 0 0 0-69.098 69.099V771.98a69.962 69.962 0 0 0 69.098 69.098h475.911A69.962 69.962 0 0 0 797.9 771.98V503.363a60.46 60.46 0 1 1 120.922 0V771.98A190.883 190.883 0 0 1 728.802 962z"></path></svg><!--]-->Found Error? Edit this page on GitHub<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span><!----></a></div><div class="meta-item git-info"><div class="update-time"><span class="label">Last update: </span><!----></div><div class="contributors"><span class="label">Contributors: </span><!--[--><!--[--><span class="contributor" title="email: 43237967+2b3c511@users.noreply.github.com">Summer</span><!--]--><!--]--></div></div></footer><nav class="vp-page-nav"><a class="vp-link nav-link prev" href="/UserGuide/V1.0.x/Operators-Functions/Conversion.html"><div class="hint"><span class="arrow start"></span>Prev</div><div class="link"><!---->Conversion</div></a><a class="vp-link nav-link next" href="/UserGuide/V1.0.x/Operators-Functions/Selection.html"><div class="hint">Next<span class="arrow end"></span></div><div class="link">Selection<!----></div></a></nav><!----><!----><!--]--></main><!--]--><footer style="padding-bottom:2rem;"><span id="doc-version" style="display:none;">rel/1.0</span><p style="text-align:center;color:#909399;font-size:12px;margin:0 30px;">Copyright © 2023 The Apache Software Foundation.<br> Apache and the Apache feather logo are trademarks of The Apache Software Foundation</p><p style="text-align:center;margin-top:10px;color:#909399;font-size:12px;margin:0 30px;"><strong>Have a question?</strong> Connect with us on QQ, WeChat, or Slack. <a href="https://github.com/apache/iotdb/issues/1995">Join the community</a> now.</p><p style="text-align:center;margin-top:10px;color:#909399;font-size:12px;margin:0 30px;"> We use <a href="https://analytics.google.com">Google Analytics</a> to collect anonymous, aggregated usage information. </p></footer></div><!--]--><!--]--><!----><!--]--></div>
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