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    <div>
     <h3 class="title">
      <a name="help">
      </a>
      15.8.3 HELP Statement
     </h3>
    </div>
   </div>
  </div>
  <a class="indexterm" name="idm46045167898720">
  </a>
  <div class="copytoclipboard-wrapper">
   <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa95251764"><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">HELP</span> <span class="token string">'<em class="replaceable">search_string</em>'</span></code></pre>
  </div>
  <p>
   The
   <a class="link" href="help.html" title="15.8.3 HELP Statement">
    <code class="literal">
     HELP
    </code>
   </a>
   statement returns online
      information from the MySQL Reference Manual. Its proper operation
      requires that the help tables in the
   <code class="literal">
    mysql
   </code>
   database be initialized with help topic information (see
   <a class="xref" href="server-side-help-support.html" title="7.1.17 Server-Side Help Support">
    Section 7.1.17, “Server-Side Help Support”
   </a>
   ).
  </p>
  <p>
   The
   <a class="link" href="help.html" title="15.8.3 HELP Statement">
    <code class="literal">
     HELP
    </code>
   </a>
   statement searches the
      help tables for the given search string and displays the result of
      the search. The search string is not case-sensitive.
  </p>
  <p>
   The search string can contain the wildcard characters
   <code class="literal">
    %
   </code>
   and
   <code class="literal">
    _
   </code>
   . These have the same
      meaning as for pattern-matching operations performed with the
   <a class="link" href="string-comparison-functions.html#operator_like">
    <code class="literal">
     LIKE
    </code>
   </a>
   operator. For example,
   <code class="literal">
    HELP 'rep%'
   </code>
   returns a list of topics that begin
      with
   <code class="literal">
    rep
   </code>
   .
  </p>
  <p>
   The
   <code class="literal">
    HELP
   </code>
   statement does not require a
      terminator such as
   <code class="literal">
    ;
   </code>
   or
   <code class="literal">
    \G
   </code>
   .
  </p>
  <p>
   The
   <code class="literal">
    HELP
   </code>
   statement understands several types of
      search strings:
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      At the most general level, use
      <code class="literal">
       contents
      </code>
      to
          retrieve a list of the top-level help categories:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa27478055"><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">HELP</span> <span class="token string">'contents'</span></code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      For a list of topics in a given help category, such as
      <code class="literal">
       Data Types
      </code>
      , use the category name:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting one-line language-sql"><div class="docs-select-all right" id="sa60464504"><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">HELP</span> <span class="token string">'data types'</span></code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      For help on a specific help topic, such as the
      <a class="link" href="string-functions.html#function_ascii">
       <code class="literal">
        ASCII()
       </code>
      </a>
      function or the
      <a class="link" href="create-table.html" title="15.1.20 CREATE TABLE Statement">
       <code class="literal">
        CREATE TABLE
       </code>
      </a>
      statement, use the
          associated keyword or keywords:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-sql"><div class="docs-select-all right" id="sa95205477"><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">HELP</span> <span class="token string">'ascii'</span>
<span class="token keyword">HELP</span> <span class="token string">'create table'</span></code></pre>
     </div>
    </li>
   </ul>
  </div>
  <p>
   In other words, the search string matches a category, many topics,
      or a single topic. The following descriptions indicate the forms
      that the result set can take.
  </p>
  <div class="itemizedlist">
   <ul class="itemizedlist" style="list-style-type: disc; ">
    <li class="listitem">
     <p>
      Empty result
     </p>
     <p>
      No match could be found for the search string.
     </p>
     <p>
      Example:
      <code class="literal">
       HELP 'fake'
      </code>
     </p>
     <p>
      Yields:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-none"><div class="docs-select-all right" id="sa17793921"><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-none">Nothing found
Please try to run 'help contents' for a list of all accessible topics</code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      Result set containing a single row
     </p>
     <p>
      This means that the search string yielded a hit for the help
          topic. The result includes the following items:
     </p>
     <div class="itemizedlist">
      <ul class="itemizedlist" style="list-style-type: circle; ">
       <li class="listitem">
        <p>
         <code class="literal">
          name
         </code>
         : The topic name.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          description
         </code>
         : Descriptive help text for
              the topic.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          example
         </code>
         : One or more usage examples.
              (May be empty.)
        </p>
       </li>
      </ul>
     </div>
     <p>
      Example:
      <code class="literal">
       HELP 'log'
      </code>
     </p>
     <p>
      Yields:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-none"><div class="docs-select-all right" id="sa34214694"><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-none">Name: 'LOG'
Description:
Syntax:
LOG(X), LOG(B,X)

If called with one parameter, this function returns the natural
logarithm of X. If X is less than or equal to 0.0E0, the function
returns NULL and a warning "Invalid argument for logarithm" is
reported. Returns NULL if X or B is NULL.

The inverse of this function (when called with a single argument) is
the EXP() function.

URL: https://dev.mysql.com/doc/refman/8.4/en/mathematical-functions.html

Examples:
mysql&gt; SELECT LOG(2);
        -&gt; 0.69314718055995
mysql&gt; SELECT LOG(-2);
        -&gt; NULL</code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      List of topics.
     </p>
     <p>
      This means that the search string matched multiple help
          topics.
     </p>
     <p>
      Example:
      <code class="literal">
       HELP 'status'
      </code>
     </p>
     <p>
      Yields:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-none"><div class="docs-select-all right" id="sa9032732"><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-none">Many help items for your request exist.
To make a more specific request, please type 'help &lt;item&gt;',
where &lt;item&gt; is one of the following topics:
   FLUSH
   SHOW
   SHOW BINARY LOG STATUS
   SHOW ENGINE
   SHOW FUNCTION STATUS
   SHOW PROCEDURE STATUS
   SHOW REPLICA STATUS
   SHOW STATUS
   SHOW TABLE STATUS</code></pre>
     </div>
    </li>
    <li class="listitem">
     <p>
      List of topics.
     </p>
     <p>
      A list is also displayed if the search string matches a
          category.
     </p>
     <p>
      Example:
      <code class="literal">
       HELP 'functions'
      </code>
     </p>
     <p>
      Yields:
     </p>
     <div class="copytoclipboard-wrapper">
      <pre class="programlisting language-none"><div class="docs-select-all right" id="sa78487844"><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-none">You asked for help about help category: "Functions"
For more information, type 'help &lt;item&gt;', where &lt;item&gt; is one of the following
categories:
   Aggregate Functions and Modifiers
   Bit Functions
   Cast Functions and Operators
   Comparison Operators
   Date and Time Functions
   Encryption Functions
   Enterprise Encryption Functions
   Flow Control Functions
   GROUP BY Functions and Modifiers
   GTID
   Information Functions
   Internal Functions
   Locking Functions
   Logical Operators
   Miscellaneous Functions
   Numeric Functions
   Performance Schema Functions
   Spatial Functions
   String Functions
   Window Functions
   XML</code></pre>
     </div>
    </li>
   </ul>
  </div>
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