Files
impala/docs/topics/impala_langref.xml
Jim Apple 3be0f122a5 IMPALA-3398: Add docs to main Impala branch.
These are refugees from doc_prototype. They can be rendered with the
DITA Open Toolkit version 2.3.3 by:

/tmp/dita-ot-2.3.3/bin/dita \
  -i impala.ditamap \
  -f html5 \
  -o $(mktemp -d) \
  -filter impala_html.ditaval

Change-Id: I8861e99adc446f659a04463ca78c79200669484f
Reviewed-on: http://gerrit.cloudera.org:8080/5014
Reviewed-by: John Russell <jrussell@cloudera.com>
Tested-by: John Russell <jrussell@cloudera.com>
2016-11-17 22:38:44 +00:00

75 lines
2.9 KiB
XML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="langref">
<title>Impala SQL Language Reference</title>
<titlealts audience="PDF"><navtitle>SQL Reference</navtitle></titlealts>
<prolog>
<metadata>
<data name="Category" value="Impala"/>
<data name="Category" value="SQL"/>
<data name="Category" value="Data Analysts"/>
<data name="Category" value="Developers"/>
<data name="Category" value="impala-shell"/>
</metadata>
</prolog>
<conbody>
<p>
Impala uses SQL as its query language. To protect user investment in skills development and query
design, Impala provides a high degree of compatibility with the Hive Query Language (HiveQL):
</p>
<ul>
<li>
Because Impala uses the same metadata store as Hive to record information about table structure and
properties, Impala can access tables defined through the native Impala <codeph>CREATE TABLE</codeph>
command, or tables created using the Hive data definition language (DDL).
</li>
<li>
Impala supports data manipulation (DML) statements similar to the DML component of HiveQL.
</li>
<li>
Impala provides many <xref href="impala_functions.xml#builtins">built-in functions</xref> with the same
names and parameter types as their HiveQL equivalents.
</li>
</ul>
<p>
Impala supports most of the same <xref href="impala_langref_sql.xml#langref_sql">statements and
clauses</xref> as HiveQL, including, but not limited to <codeph>JOIN</codeph>, <codeph>AGGREGATE</codeph>,
<codeph>DISTINCT</codeph>, <codeph>UNION ALL</codeph>, <codeph>ORDER BY</codeph>, <codeph>LIMIT</codeph> and
(uncorrelated) subquery in the <codeph>FROM</codeph> clause. Impala also supports <codeph>INSERT
INTO</codeph> and <codeph>INSERT OVERWRITE</codeph>.
</p>
<p>
Impala supports data types with the same names and semantics as the equivalent Hive data types:
<codeph>STRING</codeph>, <codeph>TINYINT</codeph>, <codeph>SMALLINT</codeph>, <codeph>INT</codeph>,
<codeph>BIGINT</codeph>, <codeph>FLOAT</codeph>, <codeph>DOUBLE</codeph>, <codeph>BOOLEAN</codeph>,
<codeph>STRING</codeph>, <codeph>TIMESTAMP</codeph>.
</p>
<p>
For full details about Impala SQL syntax and semantics, see
<xref href="impala_langref_sql.xml#langref_sql"/>.
</p>
<p>
Most HiveQL <codeph>SELECT</codeph> and <codeph>INSERT</codeph> statements run unmodified with Impala. For
information about Hive syntax not available in Impala, see
<xref href="impala_langref_unsupported.xml#langref_hiveql_delta"/>.
</p>
<p>
For a list of the built-in functions available in Impala queries, see
<xref href="impala_functions.xml#builtins"/>.
</p>
<p outputclass="toc"/>
</conbody>
</concept>