<div id="docs-body">
 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h3 class="title">
      <a name="partitioning-info">
      </a>
      26.3.5 Obtaining Information About Partitions
     </h3>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045083422496">
  </a>
  <a class="indexterm" name="idm46045083421440">
  </a>
  <a class="indexterm" name="idm46045083420352">
  </a>
  <a class="indexterm" name="idm46045083419264">
  </a>
  <p>
   This section discusses obtaining information about existing
        partitions, which can be done in a number of ways. Methods of
        obtaining such information include the following:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Using the
      <a class="link" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
       <code class="literal">
        SHOW CREATE TABLE
       </code>
      </a>
      statement to view the partitioning clauses used in creating
            a partitioned table.
     </p>
    </li>
    <li class="listitem">
     <p>
      Using the
      <a class="link" href="show-table-status.html" title="15.7.7.38 SHOW TABLE STATUS Statement">
       <code class="literal">
        SHOW TABLE STATUS
       </code>
      </a>
      statement to determine whether a table is partitioned.
     </p>
    </li>
    <li class="listitem">
     <p>
      Querying the Information Schema
      <a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
       <code class="literal">
        PARTITIONS
       </code>
      </a>
      table.
     </p>
    </li>
    <li class="listitem">
     <p>
      Using the statement
      <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
       <code class="literal">
        EXPLAIN
            SELECT
       </code>
      </a>
      to see which partitions are used by a given
      <a class="link" href="select.html" title="15.2.13 SELECT Statement">
       <code class="literal">
        SELECT
       </code>
      </a>
      .
     </p>
    </li>
   </ul>
  </div>
  <p>
   When insertions, deletions, or updates are made to partitioned
        tables, the binary log records information about the partition
        and (if any) the subpartition in which the row event took place.
        A new row event is created for a modification that takes place
        in a different partition or subpartition, even if the table
        involved is the same. So if a transaction involves three
        partitions or subpartitions, three row events are generated. For
        an update event, the partition information is recorded for both
        the
   <span class="quote">
    “
    <span class="quote">
     before
    </span>
    ”
   </span>
   image and the
   <span class="quote">
    “
    <span class="quote">
     after
    </span>
    ”
   </span>
   image. The partition information is displayed if you specify the
   <code class="literal">
    -v
   </code>
   or
   <code class="literal">
    --verbose
   </code>
   option
        when viewing the binary log using
   <a class="link" href="mysqlbinlog.html" title="6.6.9 mysqlbinlog — Utility for Processing Binary Log Files">
    <span class="command">
     <strong>
      mysqlbinlog
     </strong>
    </span>
   </a>
   . Partition information is only
        recorded when row-based logging is in use
        (
   <a class="link" href="replication-options-binary-log.html#sysvar_binlog_format">
    <code class="literal">
     binlog_format=ROW
    </code>
   </a>
   ).
  </p>
  <p>
   As discussed elsewhere in this chapter,
   <a class="link" href="show-create-table.html" title="15.7.7.11 SHOW CREATE TABLE Statement">
    <code class="literal">
     SHOW CREATE TABLE
    </code>
   </a>
   includes in its
        output the
   <code class="literal">
    PARTITION BY
   </code>
   clause used to create
        a partitioned table. For example:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa54910540"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">SHOW</span> <span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> trb3\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
       Table<span class="token punctuation">:</span> trb3
Create Table<span class="token punctuation">:</span> CREATE TABLE `trb3` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(50) DEFAULT NULL,
  `purchased` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci
/<span class="token punctuation">*</span>!50100 PARTITION BY RANGE (YEAR(purchased))
(PARTITION p0 VALUES LESS THAN (1990) ENGINE = InnoDB,
 PARTITION p1 VALUES LESS THAN (1995) ENGINE = InnoDB,
 PARTITION p2 VALUES LESS THAN (2000) ENGINE = InnoDB,
 PARTITION p3 VALUES LESS THAN (2005) ENGINE = InnoDB) <span class="token punctuation">*</span>/
</span><span class="token output">0 row in set (0.00 sec)</span></code></pre>
  </div>
  <p>
   The output from
   <a class="link" href="show-table-status.html" title="15.7.7.38 SHOW TABLE STATUS Statement">
    <code class="literal">
     SHOW TABLE STATUS
    </code>
   </a>
   for partitioned tables is the same as that for nonpartitioned
        tables, except that the
   <code class="literal">
    Create_options
   </code>
   column
        contains the string
   <code class="literal">
    partitioned
   </code>
   . The
   <code class="literal">
    Engine
   </code>
   column contains the name of the
        storage engine used by all partitions of the table. (See
   <a class="xref" href="show-table-status.html" title="15.7.7.38 SHOW TABLE STATUS Statement">
    Section 15.7.7.38, “SHOW TABLE STATUS Statement”
   </a>
   , for more information about
        this statement.)
  </p>
  <p>
   You can also obtain information about partitions from
   <code class="literal">
    INFORMATION_SCHEMA
   </code>
   , which contains a
   <a class="link" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
    <code class="literal">
     PARTITIONS
    </code>
   </a>
   table. See
   <a class="xref" href="information-schema-partitions-table.html" title="28.3.21 The INFORMATION_SCHEMA PARTITIONS Table">
    Section 28.3.21, “The INFORMATION_SCHEMA PARTITIONS Table”
   </a>
   .
  </p>
  <a class="indexterm" name="idm46045083388336">
  </a>
  <a class="indexterm" name="idm46045083386848">
  </a>
  <p>
   It is possible to determine which partitions of a partitioned
        table are involved in a given
   <a class="link" href="select.html" title="15.2.13 SELECT Statement">
    <code class="literal">
     SELECT
    </code>
   </a>
   query using
   <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
    <code class="literal">
     EXPLAIN
    </code>
   </a>
   . The
   <code class="literal">
    partitions
   </code>
   column in the
   <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
    <code class="literal">
     EXPLAIN
    </code>
   </a>
   output lists the
        partitions from which records would be matched by the query.
  </p>
  <p>
   Suppose that a table
   <code class="literal">
    trb1
   </code>
   is created and
        populated as follows:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa49824611"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token keyword">CREATE</span> <span class="token keyword">TABLE</span> trb1 <span class="token punctuation">(</span>id <span class="token datatype">INT</span><span class="token punctuation">,</span> <span class="token keyword">name</span> <span class="token datatype">VARCHAR</span><span class="token punctuation">(</span><span class="token number">50</span><span class="token punctuation">)</span><span class="token punctuation">,</span> purchased <span class="token datatype">DATE</span><span class="token punctuation">)</span>
    <span class="token keyword">PARTITION</span> <span class="token keyword">BY</span> <span class="token keyword">RANGE</span><span class="token punctuation">(</span>id<span class="token punctuation">)</span>
    <span class="token punctuation">(</span>
        <span class="token keyword">PARTITION</span> p0 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
        <span class="token keyword">PARTITION</span> p1 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
        <span class="token keyword">PARTITION</span> p2 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
        <span class="token keyword">PARTITION</span> p3 <span class="token keyword">VALUES</span> <span class="token keyword">LESS</span> <span class="token keyword">THAN</span> <span class="token punctuation">(</span><span class="token number">11</span><span class="token punctuation">)</span>
    <span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> trb1 <span class="token keyword">VALUES</span>
    <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token string">'desk organiser'</span><span class="token punctuation">,</span> <span class="token string">'2003-10-15'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token string">'CD player'</span><span class="token punctuation">,</span> <span class="token string">'1993-11-05'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span> <span class="token string">'TV set'</span><span class="token punctuation">,</span> <span class="token string">'1996-03-10'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token string">'bookcase'</span><span class="token punctuation">,</span> <span class="token string">'1982-01-10'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span> <span class="token string">'exercise bike'</span><span class="token punctuation">,</span> <span class="token string">'2004-05-09'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token string">'sofa'</span><span class="token punctuation">,</span> <span class="token string">'1987-06-05'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">,</span> <span class="token string">'popcorn maker'</span><span class="token punctuation">,</span> <span class="token string">'2001-11-22'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">8</span><span class="token punctuation">,</span> <span class="token string">'aquarium'</span><span class="token punctuation">,</span> <span class="token string">'1992-08-04'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">,</span> <span class="token string">'study desk'</span><span class="token punctuation">,</span> <span class="token string">'1984-09-16'</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
    <span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span> <span class="token string">'lava lamp'</span><span class="token punctuation">,</span> <span class="token string">'1998-12-25'</span><span class="token punctuation">)</span><span class="token punctuation">;</span></code></pre>
  </div>
  <p>
   You can see which partitions are used in a query such as
   <code class="literal">
    SELECT * FROM trb1;
   </code>
   , as shown here:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa75593582"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">EXPLAIN</span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> trb1\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
           id<span class="token punctuation">:</span> 1
  select_type<span class="token punctuation">:</span> SIMPLE
        table<span class="token punctuation">:</span> trb1
   partitions<span class="token punctuation">:</span> p0,p1,p2,p3
         type<span class="token punctuation">:</span> ALL
possible_keys<span class="token punctuation">:</span> NULL
          key<span class="token punctuation">:</span> NULL
      key_len<span class="token punctuation">:</span> NULL
          ref<span class="token punctuation">:</span> NULL
         rows<span class="token punctuation">:</span> 10
        Extra<span class="token punctuation">:</span> Using filesort</span></code></pre>
  </div>
  <p>
   In this case, all four partitions are searched. However, when a
        limiting condition making use of the partitioning key is added
        to the query, you can see that only those partitions containing
        matching values are scanned, as shown here:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa62429990"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">EXPLAIN</span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> trb1 <span class="token keyword">WHERE</span> id <span class="token operator">&lt;</span> <span class="token number">5</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
           id<span class="token punctuation">:</span> 1
  select_type<span class="token punctuation">:</span> SIMPLE
        table<span class="token punctuation">:</span> trb1
   partitions<span class="token punctuation">:</span> p0,p1
         type<span class="token punctuation">:</span> ALL
possible_keys<span class="token punctuation">:</span> NULL
          key<span class="token punctuation">:</span> NULL
      key_len<span class="token punctuation">:</span> NULL
          ref<span class="token punctuation">:</span> NULL
         rows<span class="token punctuation">:</span> 10
        Extra<span class="token punctuation">:</span> Using where</span></code></pre>
  </div>
  <p>
   <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
    <code class="literal">
     EXPLAIN
    </code>
   </a>
   also provides
        information about keys used and possible keys:
  </p>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa90032825"><div class="copy-help left">Press ⌘+C to copy</div> <div class="right"><button class="clipboard-btn" title="Copy to Clipboard"><span class="icon-clipboard"></span></button></div></div><code class="language-sql"><span class="token prompt">mysql&gt;</span> <span class="token keyword">ALTER</span> <span class="token keyword">TABLE</span> trb1 <span class="token keyword">ADD</span> <span class="token keyword">PRIMARY</span> <span class="token keyword">KEY</span> <span class="token punctuation">(</span>id<span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token output">Query OK, 10 rows affected (0.03 sec)</span>
<span class="token output">Records: 10  Duplicates: 0  Warnings: 0</span>

<span class="token prompt">mysql&gt;</span> <span class="token keyword">EXPLAIN</span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> trb1 <span class="token keyword">WHERE</span> id <span class="token operator">&lt;</span> <span class="token number">5</span>\G
<span class="token output"><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span> 1. row <span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span><span class="token punctuation">*</span>
           id<span class="token punctuation">:</span> 1
  select_type<span class="token punctuation">:</span> SIMPLE
        table<span class="token punctuation">:</span> trb1
   partitions<span class="token punctuation">:</span> p0,p1
         type<span class="token punctuation">:</span> range
possible_keys<span class="token punctuation">:</span> PRIMARY
          key<span class="token punctuation">:</span> PRIMARY
      key_len<span class="token punctuation">:</span> 4
          ref<span class="token punctuation">:</span> NULL
         rows<span class="token punctuation">:</span> 7
        Extra<span class="token punctuation">:</span> Using where</span></code></pre>
  </div>
  <p>
   If
   <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
    <code class="literal">
     EXPLAIN
    </code>
   </a>
   is used to examine a
        query against a nonpartitioned table, no error is produced, but
        the value of the
   <code class="literal">
    partitions
   </code>
   column is always
   <code class="literal">
    NULL
   </code>
   .
  </p>
  <p>
   The
   <code class="literal">
    rows
   </code>
   column of
   <a class="link" href="explain.html" title="15.8.2 EXPLAIN Statement">
    <code class="literal">
     EXPLAIN
    </code>
   </a>
   output displays the total
        number of rows in the table.
  </p>
  <p>
   See also
   <a class="xref" href="explain.html" title="15.8.2 EXPLAIN Statement">
    Section 15.8.2, “EXPLAIN Statement”
   </a>
   .
  </p>
 </div>
 <br/>
</div>
