forked from docs/doc-exports
Yang, Tong
48706b7552
Reviewed-by: Kacur, Michal <michal.kacur@t-systems.com> Co-authored-by: Yang, Tong <yangtong2@huawei.com> Co-committed-by: Yang, Tong <yangtong2@huawei.com>
43 lines
1.8 KiB
HTML
43 lines
1.8 KiB
HTML
<a name="mrs_01_24225"></a><a name="mrs_01_24225"></a>
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<h1 class="topictitle1">UDAF Java and SQL Examples</h1>
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<div id="body32001227"><div class="section" id="mrs_01_24225__en-us_topic_0000001173630762_section20119172765318"><h4 class="sectiontitle">UDAF Java Example</h4><pre class="screen" id="mrs_01_24225__en-us_topic_0000001173630762_screen1492795995316">package com.<em id="mrs_01_24225__i19547102674514">xxx</em>.udf;
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import org.apache.flink.table.functions.AggregateFunction;
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public class UdfClass_UDAF {
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public static class AverageAccumulator {
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public int sum;
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}
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public static class Average extends AggregateFunction<Integer, AverageAccumulator> {
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public void accumulate(AverageAccumulator acc, Integer value) {
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acc.sum += value;
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}
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@Override
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public Integer getValue(AverageAccumulator acc) {
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return acc.sum;
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}
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@Override
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public AverageAccumulator createAccumulator() {
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return new AverageAccumulator();
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}
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}
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}</pre>
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</div>
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<div class="section" id="mrs_01_24225__en-us_topic_0000001173630762_section1658564210543"><h4 class="sectiontitle">UDAF SQL Example</h4><pre class="screen" id="mrs_01_24225__en-us_topic_0000001173630762_screen082231218557">CREATE TEMPORARY FUNCTION udaf as 'com.<em id="mrs_01_24225__i46657183462">xxx</em>.udf.UdfClass_UDAF$Average';
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CREATE TABLE udfSource (a int) WITH ('connector' = 'datagen','rows-per-second'='1','fields.a.min'='1','fields.a.max'='3');
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CREATE TABLE udfSink (b int,c int) WITH ('connector' = 'print');
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INSERT INTO
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udfSink
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SELECT
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a,
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udaf(a)
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FROM
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udfSource group by a;</pre>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="mrs_01_24223.html">Managing UDFs</a></div>
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</div>
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</div>
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