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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept rev="1.3.0" id="window_functions">

  <title>Window Functions</title>
  <prolog>
    <metadata>
      <data name="Category" value="Impala"/>
    </metadata>
  </prolog>

  <conbody>

    <p>
      <indexterm audience="hidden">window functions</indexterm>
      Window functions are a special category of built-in functions. They produce one output value for each input
      row, like scalar functions such as <codeph>length()</codeph> or <codeph>substr()</codeph>. Yet like aggregate
      functions, they also examine the contents of multiple input rows to compute each output value.
    </p>

    <p outputclass="toc inpage"/>
  </conbody>
</concept>