assets/Aggregation.html-7a6b0ee6.js

import{_ as t,o as e,c as n,a,f as s}from"./app-0b7998a5.js";const d={},i=s(`<h1 id="aggregate-functions" tabindex="-1"><a class="header-anchor" href="#aggregate-functions" aria-hidden="true">#</a> Aggregate Functions</h1><p>Aggregate functions are many-to-one functions. They perform aggregate calculations on a set of values, resulting in a single aggregated result.</p><p>All aggregate functions except <code>COUNT()</code> ignore null values and return null when there are no input rows or all values are null. For example, <code>SUM()</code> returns null instead of zero, and <code>AVG()</code> does not include null values in the count.</p><p>The aggregate functions supported by IoTDB are as follows:</p><table><thead><tr><th>Function Name</th><th>Function Description</th><th>Allowed Input Data Types</th><th>Output Data Types</th></tr></thead><tbody><tr><td>SUM</td><td>Summation.</td><td>INT32 INT64 FLOAT DOUBLE</td><td>DOUBLE</td></tr><tr><td>COUNT</td><td>Counts the number of data points.</td><td>All types</td><td>INT</td></tr><tr><td>AVG</td><td>Average.</td><td>INT32 INT64 FLOAT DOUBLE</td><td>DOUBLE</td></tr><tr><td>EXTREME</td><td>Finds the value with the largest absolute value. Returns a positive value if the maximum absolute value of positive and negative values is equal.</td><td>INT32 INT64 FLOAT DOUBLE</td><td>Consistent with the input data type</td></tr><tr><td>MAX_VALUE</td><td>Find the maximum value.</td><td>INT32 INT64 FLOAT DOUBLE</td><td>Consistent with the input data type</td></tr><tr><td>MIN_VALUE</td><td>Find the minimum value.</td><td>INT32 INT64 FLOAT DOUBLE</td><td>Consistent with the input data type</td></tr><tr><td>FIRST_VALUE</td><td>Find the value with the smallest timestamp.</td><td>All data types</td><td>Consistent with input data type</td></tr><tr><td>LAST_VALUE</td><td>Find the value with the largest timestamp.</td><td>All data types</td><td>Consistent with input data type</td></tr><tr><td>MAX_TIME</td><td>Find the maximum timestamp.</td><td>All data Types</td><td>Timestamp</td></tr><tr><td>MIN_TIME</td><td>Find the minimum timestamp.</td><td>All data Types</td><td>Timestamp</td></tr></tbody></table><p><strong>Example:</strong> Count Points</p><div class="language-sql line-numbers-mode" data-ext="sql"><pre class="language-sql"><code><span class="token keyword">select</span> <span class="token function">count</span><span class="token punctuation">(</span><span class="token keyword">status</span><span class="token punctuation">)</span> <span class="token keyword">from</span> root<span class="token punctuation">.</span>ln<span class="token punctuation">.</span>wf01<span class="token punctuation">.</span>wt01<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>+-------------------------------+
|count(root.ln.wf01.wt01.status)|
+-------------------------------+
|                          10080|
+-------------------------------+
Total line number = 1
It costs 0.016s
</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></div>`,9);function o(r,l){return e(),n("div",null,[a(`

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`),i])}const c=t(d,[["render",o],["__file","Aggregation.html.vue"]]);export{c as default};