hive源码之concat函数

最新推荐文章于 2025-01-27 00:33:12 发布

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最新推荐文章于 2025-01-27 00:33:12 发布 · 1k 阅读

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文章标签：

#hive #hadoop #apache #大数据 #sql

文章详细介绍了Hive中内置的concat函数，从函数使用、案例演示到源码分析。在源码部分，探讨了函数如何处理不同类型的数据，如STRING、CHAR、VARCHAR，以及其在处理BINARY数据时的行为。initialize()函数用于初始化，确定返回类型，evaluate()函数则包含了实际的拼接逻辑。

大家好，我是老六。今天和大家一起来看下hive中内置函数concat的源码。

一、函数使用

hive函数官方文档：LanguageManual UDF - Apache Hive - Apache Software Foundation

二、使用案例

函数使用比较简单

结果

三、源码分析

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
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package org.apache.hadoop.hive.ql.udf.generic;

import org.apache.hadoop.hive.common.type.HiveChar;
import org.apache.hadoop.hive.common.type.HiveVarchar;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.vector.Ve