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<h1 align="center">SQL As Understood By SQLite</h1><p><a href="lang.html">[Top]</a></p><h2>EXPLAIN</h2><h4><a href="syntaxdiagrams.html#sql-stmt">sql-stmt:</a></h4><blockquote> <img alt="syntax diagram sql-stmt" src="images/syntax/sql-stmt.gif"></img> </blockquote>
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<p>An SQL statement can be preceded by the keyword "EXPLAIN" or
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by the phrase "EXPLAIN QUERY PLAN". Either modification causes the
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SQL statement to behave as a query and to return information about
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how the SQL statement would have operated if the EXPLAIN keyword or
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phrase had been omitted.</p>
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<p>The output from EXPLAIN and EXPLAIN QUERY PLAN is intended for
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interactive analysis and troubleshooting only. The details of the
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output format are subject to change from one release of SQLite to the next.
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Applications should not use EXPLAIN or EXPLAIN QUERY PLAN since
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their exact behavior is variable and only partially documented.</p>
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<p>When the EXPLAIN keyword appears by itself it causes the statement
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to behave as a query that returns the sequence of
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<a href="opcode.html">virtual machine instructions</a> it would have used to execute the command had
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the EXPLAIN keyword not been present. When the EXPLAIN QUERY PLAN phrase
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appears, the statement returns high-level information regarding the query
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plan that would have been used.
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The EXPLAIN QUERY PLAN command is described in
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<a href="eqp.html">more detail here</a>.