docs/build/plain-html/topics/impala_dml.html - impala - Git at Google

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   <h1 class="title topictitle1" id="ariaid-title1">DML Statements</h1>


   <div class="body conbody">

     <p class="p">
       DML refers to <span class="q">"Data Manipulation Language"</span>, a subset of SQL statements that modify the data stored in
       tables. Because Impala focuses on query performance and leverages the append-only nature of HDFS storage,
       currently Impala only supports a small set of DML statements:
     </p>


     <ul class="ul">
       <li class="li">
         <a class="xref" href="impala_delete.html">DELETE Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
       </li>


       <li class="li">
         <a class="xref" href="impala_insert.html">INSERT Statement</a>.
       </li>


       <li class="li">
         <a class="xref" href="impala_load_data.html">LOAD DATA Statement</a>. Does not apply for HBase or Kudu tables.
       </li>


       <li class="li">
         <a class="xref" href="impala_update.html">UPDATE Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
       </li>


       <li class="li">
         <a class="xref" href="impala_upsert.html">UPSERT Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
       </li>

     </ul>


     <p class="p">
       <code class="ph codeph">INSERT</code> in Impala is primarily optimized for inserting large volumes of data in a single
       statement, to make effective use of the multi-megabyte HDFS blocks. This is the way in Impala to create new
       data files. If you intend to insert one or a few rows at a time, such as using the <code class="ph codeph">INSERT ...
       VALUES</code> syntax, that technique is much more efficient for Impala tables stored in HBase. See
       <a class="xref" href="impala_hbase.html#impala_hbase">Using Impala to Query HBase Tables</a> for details.
     </p>


     <p class="p">
       <code class="ph codeph">LOAD DATA</code> moves existing data files into the directory for an Impala table, making them
       immediately available for Impala queries. This is one way in Impala to work with data files produced by other
       Hadoop components. (<code class="ph codeph">CREATE EXTERNAL TABLE</code> is the other alternative; with external tables,
       you can query existing data files, while the files remain in their original location.)
     </p>


     <p class="p">
       In <span class="keyword">Impala 2.8</span> and higher, Impala does support the <code class="ph codeph">UPDATE</code>, <code class="ph codeph">DELETE</code>,
       and <code class="ph codeph">UPSERT</code> statements for Kudu tables.
       For HDFS or S3 tables, to simulate the effects of an <code class="ph codeph">UPDATE</code> or <code class="ph codeph">DELETE</code> statement
       in other database systems, typically you use <code class="ph codeph">INSERT</code> or <code class="ph codeph">CREATE TABLE AS SELECT</code> to copy data
       from one table to another, filtering out or changing the appropriate rows during the copy operation.
     </p>


     <p class="p">
       You can also achieve a result similar to <code class="ph codeph">UPDATE</code> by using Impala tables stored in HBase.
       When you insert a row into an HBase table, and the table
       already contains a row with the same value for the key column, the older row is hidden, effectively the same
       as a single-row <code class="ph codeph">UPDATE</code>.
     </p>


     <p class="p">
       Impala can perform DML operations for tables or partitions stored in the Amazon S3 filesystem
       with <span class="keyword">Impala 2.6</span> and higher. See <a class="xref" href="impala_s3.html#s3">Using Impala with Amazon S3 Object Store</a> for details.
     </p>


     <p class="p">
         <strong class="ph b">Related information:</strong>
       </p>


     <p class="p">
       The other major classifications of SQL statements are data definition language (see
       <a class="xref" href="impala_ddl.html#ddl">DDL Statements</a>) and queries (see <a class="xref" href="impala_select.html#select">SELECT Statement</a>).
     </p>

   </div>

 <div class="related-links">
 <div class="familylinks">
 <div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_langref_sql.html">Impala SQL Statements</a></div>
 </div>
 </div></body>
 </html>
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	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
	<head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

	<meta name="copyright" content="(C) Copyright 2025" />
	<meta name="DC.rights.owner" content="(C) Copyright 2025" />
	<meta name="DC.Type" content="concept" />
	<meta name="DC.Title" content="DML Statements" />
	<meta name="DC.Relation" scheme="URI" content="../topics/impala_langref_sql.html" />
	<meta name="prodname" content="Impala" />
	<meta name="prodname" content="Impala" />
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	<meta name="version" content="Impala 3.4.x" />
	<meta name="DC.Format" content="XHTML" />
	<meta name="DC.Identifier" content="dml" />
	<link rel="stylesheet" type="text/css" href="../commonltr.css" />
	<title>DML Statements</title>
	</head>
	<body id="dml">


	<h1 class="title topictitle1" id="ariaid-title1">DML Statements</h1>



	<div class="body conbody">

	<p class="p">
	DML refers to <span class="q">"Data Manipulation Language"</span>, a subset of SQL statements that modify the data stored in
	tables. Because Impala focuses on query performance and leverages the append-only nature of HDFS storage,
	currently Impala only supports a small set of DML statements:
	</p>


	<ul class="ul">
	<li class="li">
	<a class="xref" href="impala_delete.html">DELETE Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
	</li>


	<li class="li">
	<a class="xref" href="impala_insert.html">INSERT Statement</a>.
	</li>


	<li class="li">
	<a class="xref" href="impala_load_data.html">LOAD DATA Statement</a>. Does not apply for HBase or Kudu tables.
	</li>


	<li class="li">
	<a class="xref" href="impala_update.html">UPDATE Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
	</li>


	<li class="li">
	<a class="xref" href="impala_upsert.html">UPSERT Statement (Impala 2.8 or higher only)</a>. Works for Kudu tables only.
	</li>

	</ul>


	<p class="p">
	<code class="ph codeph">INSERT</code> in Impala is primarily optimized for inserting large volumes of data in a single
	statement, to make effective use of the multi-megabyte HDFS blocks. This is the way in Impala to create new
	data files. If you intend to insert one or a few rows at a time, such as using the <code class="ph codeph">INSERT ...
	VALUES</code> syntax, that technique is much more efficient for Impala tables stored in HBase. See
	<a class="xref" href="impala_hbase.html#impala_hbase">Using Impala to Query HBase Tables</a> for details.
	</p>


	<p class="p">
	<code class="ph codeph">LOAD DATA</code> moves existing data files into the directory for an Impala table, making them
	immediately available for Impala queries. This is one way in Impala to work with data files produced by other
	Hadoop components. (<code class="ph codeph">CREATE EXTERNAL TABLE</code> is the other alternative; with external tables,
	you can query existing data files, while the files remain in their original location.)
	</p>


	<p class="p">
	In <span class="keyword">Impala 2.8</span> and higher, Impala does support the <code class="ph codeph">UPDATE</code>, <code class="ph codeph">DELETE</code>,
	and <code class="ph codeph">UPSERT</code> statements for Kudu tables.
	For HDFS or S3 tables, to simulate the effects of an <code class="ph codeph">UPDATE</code> or <code class="ph codeph">DELETE</code> statement
	in other database systems, typically you use <code class="ph codeph">INSERT</code> or <code class="ph codeph">CREATE TABLE AS SELECT</code> to copy data
	from one table to another, filtering out or changing the appropriate rows during the copy operation.
	</p>


	<p class="p">
	You can also achieve a result similar to <code class="ph codeph">UPDATE</code> by using Impala tables stored in HBase.
	When you insert a row into an HBase table, and the table
	already contains a row with the same value for the key column, the older row is hidden, effectively the same
	as a single-row <code class="ph codeph">UPDATE</code>.
	</p>


	<p class="p">
	Impala can perform DML operations for tables or partitions stored in the Amazon S3 filesystem
	with <span class="keyword">Impala 2.6</span> and higher. See <a class="xref" href="impala_s3.html#s3">Using Impala with Amazon S3 Object Store</a> for details.
	</p>


	<p class="p">
	<strong class="ph b">Related information:</strong>
	</p>


	<p class="p">
	The other major classifications of SQL statements are data definition language (see
	<a class="xref" href="impala_ddl.html#ddl">DDL Statements</a>) and queries (see <a class="xref" href="impala_select.html#select">SELECT Statement</a>).
	</p>

	</div>

	<div class="related-links">
	<div class="familylinks">
	<div class="parentlink"><strong>Parent topic:</strong> <a class="link" href="../topics/impala_langref_sql.html">Impala SQL Statements</a></div>
	</div>
	</div></body>
	</html>