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<div class=nosearch><h1 align="center">SQL As Understood By SQLite</h1><p><a href="lang.html">[Top]</a></p><h2>EXPLAIN</h2></div><p><b><a href="syntax/sql-stmt.html">sql-stmt:</a></b></p><div class='imgcontainer'>
 <img alt="syntax diagram sql-stmt" src="images/syntax/sql-stmt.gif"></img>
 </div>


<p>An SQL statement can be preceded by the keyword "EXPLAIN" or
by the phrase "EXPLAIN QUERY PLAN".  Either modification causes the
SQL statement to behave as a query and to return information about
how the SQL statement would have operated if the EXPLAIN keyword or
phrase had been omitted.</p>

<p>The output from EXPLAIN and EXPLAIN QUERY PLAN is intended for
interactive analysis and troubleshooting only.  The details of the 
output format are subject to change from one release of SQLite to the next.
Applications should not use EXPLAIN or EXPLAIN QUERY PLAN since
their exact behavior is variable and only partially documented.</p>

<p>When the EXPLAIN keyword appears by itself it causes the statement
to behave as a query that returns the sequence of 
<a href="opcode.html">virtual machine instructions</a> it would have used to execute the command had
the EXPLAIN keyword not been present. When the EXPLAIN QUERY PLAN phrase
appears, the statement returns high-level information regarding the query
plan that would have been used.

The EXPLAIN QUERY PLAN command is described in 
<a href="eqp.html">more detail here</a>.