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关于mysql学习的 中文教程

  <li>MyISAM tables now allow keys on <code>NULL</code> and <code>BLOB/TEXT</code> columns. </li>
  <li>The following join is now much faster: <code>SELECT ... FROM t1 LEFT JOIN t2 ON ... 
    WHERE t2.not_null_column IS NULL</code>. </li>
  <li><code>ORDER BY</code> and <code>GROUP BY</code> can be done on functions. </li>
  <li>Changed handling of 'const_item' to allow handling of <code>ORDER BY RAND()</code>. </li>
  <li>Indexes are now used for <code>WHERE key_column = function</code>. </li>
  <li>Indexes are now used for <code>WHERE key_column = column_name</code> even if the columns 
    are not identically packed. </li>
  <li>Indexes are now used for <code>WHERE column_name IS NULL</code>. </li>
  <li>Changed heap tables to be stored in low_byte_first order (to make it easy to convert to 
    MyISAM tables) </li>
  <li>Automatic change of HEAP temporary tables to MyISAM tables in case of 'table is full' 
    errors. </li>
  <li>Added option <code>--init-file=file_name</code> to <code>mysqld</code>. </li>
  <li><code>COUNT(DISTINCT value,[value,...])</code> </li>
  <li><code>CREATE TEMPORARY TABLE</code> now creates a temporary table, in its own namespace, 
    that is automatically deleted if connection is dropped. </li>
  <li>New keywords (required for <code>CASE</code>): <code>CASE, THEN, WHEN, ELSE and END</code>. 
  </li>
  <li>New functions <code>EXPORT_SET()</code> and <code>MD5()</code>. </li>
  <li>Support for the GB2312 Chinese character set. </li>
</ul>

<h3><a href="manual_toc.html#News-3.23.1" name="News-3.23.1">D.1.7 Changes in release 
3.23.1</a></h3>

<ul>
  <li>Fixed some compilation problems. </li>
</ul>

<h3><a href="manual_toc.html#News-3.23.0" name="News-3.23.0">D.1.8 Changes in release 
3.23.0</a></h3>

<ul>
  <p>A new table handler library (<code>MyISAM</code>) with a lot of new features. See 
  section <a href="manual_Server.html#Table_types">9.4 MySQL table types</a>. </p>
  <li>You can create in-memory <code>HEAP</code> tables which are extremely fast for lookups. </li>
  <li>Support for big files (63 bit) on OSes that support big files. </li>
  <li>New function <code>LOAD_FILE(filename)</code> to get the contents of a file as a string 
    value. </li>
  <li>New operator <code>&lt;=&gt;</code> which will act as <code>=</code> but will return 
    TRUE if both arguments are <code>NULL</code>. This is useful for comparing changes between 
    tables. </li>
  <li>Added the ODBC 3.0 <code>EXTRACT(interval FROM datetime)</code> function. </li>
  <li>Columns defined as <code>FLOAT(X)</code> is not rounded on storage and may be in 
    scientific notation (1.0 E+10) when retrieved. </li>
  <li><code>REPLACE</code> is now faster than before. </li>
  <li>Changed <code>LIKE</code> character comparison to behave as <code>=</code>; This means 
    that <code>'e' LIKE ''e'</code> is now true. </li>
  <li><code>SHOW TABLE STATUS</code> returns a lot of information about the tables. </li>
  <li>Added <code>LIKE</code> to the <code>SHOW STATUS</code> command. </li>
  <li>Added privilege column to <code>SHOW COLUMNS</code>. </li>
  <li>Added columns <code>packed</code> and <code>comment</code> to <code>SHOW INDEX</code>. </li>
  <li>Added comments to tables (with <code>CREATE TABLE ... COMMENT &quot;xxx&quot;</code>). </li>
  <li>Added <code>UNIQUE</code>, as in <code>CREATE TABLE table_name (col int not null UNIQUE)</code> 
  </li>
  <li>New create syntax: <code>CREATE TABLE table_name SELECT ....</code> </li>
  <li>New create syntax: <code>CREATE TABLE IF NOT EXISTS ...</code> </li>
  <li>Allow creation of <code>CHAR(0)</code> columns. </li>
  <li><code>DATE_FORMAT()</code> now requires <samp>`%'</samp> before any format character. </li>
  <li><code>DELAYED</code> is now a reserved word (sorry about that :( ). </li>
  <li>An example procedure is added: <code>analyse</code>, file: <tt>`sql_analyse.c'</tt>. 
    This will describe the data in your query. Try the following: <pre>SELECT ... FROM ... WHERE ... PROCEDURE ANALYSE([max elements,[max memory]])
</pre>
    <p>This procedure is extremely useful when you want to check the data in your table! </p>
  </li>
  <li><code>BINARY</code> cast to force a string to be compared case sensitively. </li>
  <li>Added option <code>--skip-show-database</code> to <code>mysqld</code>. </li>
  <li>Check if a row has changed in an <code>UPDATE</code> now also works with <code>BLOB</code>/<code>TEXT</code> 
    columns. </li>
  <li>Added the <code>INNER</code> join syntax. <strong>NOTE</strong>: This made <code>INNER</code> 
    an reserved word! </li>
  <li>Added support for netmasks to the hostname in the <strong>MySQL</strong> tables. You can 
    specify a netmask using the <code>IP/NETMASK</code> syntax. </li>
  <li>If you compare a <code>NOT NULL DATE/DATETIME</code> column with <code>IS NULL</code>, 
    this is changed to a compare against <code>0</code> to satisfy some ODBC applications. (By 
    <a href="mailto:[e-mail]">[e-mail]</a>). </li>
  <li><code>NULL IN (...)</code> now returns <code>NULL</code> instead of <code>0</code>. This 
    will ensure that <code>null_column NOT IN (...)</code> doesn't match <code>NULL</code> 
    values. </li>
  <li>Fix storage of floating point values in <code>TIME</code> columns. </li>
  <li>Changed parsing of <code>TIME</code> strings to be more strict. Now the fractional 
    second part is detected (and currently skipped). The following formats are supported: <dl
    compact>
      <dt><code>[[DAYS] [H]H:]MM:]SS[.fraction]</code> </dt>
      <dd>　</dd>
      <dt><code>[[[[[H]H]H]H]MM]SS[.fraction]</code> </dt>
      <dd>　</dd>
    </dl>
  </li>
  <li>Detect (and ignore) second fraction part from <code>DATETIME</code>. </li>
  <li>Added the <code>LOW_PRIORITY</code> attribute to <code>LOAD DATA INFILE</code>. </li>
  <li>The default index name now uses the same case as the used column name. </li>
  <li>Changed default number of connections to 100. </li>
  <li>Use bigger buffers when using <code>LOAD DATA INFILE</code>. </li>
  <li><code>DECIMAL(x,y)</code> now works according to ANSI SQL. </li>
  <li>Added aggregate UDF functions. Thanks to Andreas F. Bobak </li>
  <li><code>LAST_INSERT_ID()</code> is now updated for <code>INSERT INTO ... SELECT</code>. </li>
  <li>Some small changes to the join table optimizer to make some joins faster. </li>
  <li><code>SELECT DISTINCT</code> is much faster; It uses the new <code>UNIQUE</code> 
    functionality in <code>MyISAM</code>. One difference compared to <strong>MySQL</strong> 
    3.22 is that the output of <code>DISTINCT</code> is not sorted anymore. </li>
  <li>All C client API macros are now functions to make shared libraries more reliable. 
    Because of this, you can no longer call <code>mysql_num_fields()</code> on a <code>MYSQL</code> 
    object, you must use <code>mysql_field_count()</code> instead. </li>
  <li>Added use of <code>LIBEWRAP</code>; Patch by Henning P . Schmiedehausen. </li>
  <li>Don't allow <code>AUTO_INCREMENT</code> for other than numerical columns. </li>
  <li>Using <code>AUTO_INCREMENT</code> will now automatically make the column <code>NOT NULL</code>. 
  </li>
  <li>Show <code>NULL</code> as the default value for AUTO_INCREMENT columns. </li>
  <li>Added <code>SQL_BIG_RESULT</code>; <code>SQL_SMALL_RESULT</code> is now default. </li>
  <li>Added a shared library RPM. This enchancement was contributed by David Fox 
    ([e-mail]). </li>
  <li>Added a <code>--enable-large-files/--disable-large-files</code> switch to <code>configure</code>. 
    See <tt>`configure.in'</tt> for some systems where this is automatically turned off 
    because of broken implementations. </li>
  <li>Upgraded <code>readline</code> to 4.0. </li>
  <li>New <code>CREATE TABLE</code> options: <code>PACK_KEYS</code> and <code>CHECKSUM</code>. 
  </li>
  <li>Added <code>mysqld</code> option <code>--default-table-type</code>. </li>
</ul>

<h2><a href="manual_toc.html#News-3.22.x" name="News-3.22.x">D.2 Changes in release 3.22.x</a></h2>

<p>The 3.22 version has faster and safer connect code and a lot of new nice enhancements. 
The reason for not including these changes in the 3.21 version is mainly that we are 
trying to avoid big changes to 3.21 to keep it as stable as possible. As there aren't 
really any MAJOR changes, upgrading to 3.22 should be very easy and painless. See section <a
href="manual_Installing.html#Upgrading-from-3.21">4.16.2 Upgrading from a 3.21 version to 
3.22</a>. </p>

<p>3.22 should also be used with the new <code>DBD-mysql</code> (1.20xx) driver that can 
use the new connect protocol! </p>

<h3><a href="manual_toc.html#News-3.22.28" name="News-3.22.28">D.2.1 Changes in release 
3.22.28</a></h3>

<ul>
  <li>Fixed problem with <code>LEFT JOIN</code> and <code>COUNT()</code> on a column which was 
    declared <code>NULL</code> + and it had a <code>DEFAULT</code> value. </li>
  <li>Fixed core dump problem when using <code>CONCAT()</code> in a <code>WHERE</code> clause. 
  </li>
  <li>Fixed problem with <code>AVG()</code> and <code>STD()</code> with <code>NULL</code> 
    values. </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.27" name="News-3.22.27">D.2.2 Changes in release 
3.22.27</a></h3>

<ul>
  <li>Fixed prototype in <tt>`my_ctype.h'</tt> when using other character sets. </li>
  <li>Some configure issues to fix problems with big file system detection. </li>
  <li>Fixed problem when sorting on big blob columns. </li>
  <li><code>ROUND()</code> will now work on Win32. </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.26" name="News-3.22.26">D.2.3 Changes in release 
3.22.26</a></h3>

<ul>
  <li>Fixed core dump with empty <code>BLOB/TEXT</code> column to <code>REVERSE()</code>. </li>
  <li>Extended <code>/*! */</code> with version numbers. </li>
  <li>Changed <code>SUBSTRING(text FROM pos)</code> to conform to ANSI SQL. (Before this 
    construct returned the rightmost 'pos' characters). </li>
  <li>Fixed problem with <code>LOCK TABLES</code> combined with <code>DELETE FROM table</code> 
  </li>
  <li>Fixed problem that INSERT ... SELECT didn't use SQL_BIG_TABLES. </li>
  <li><code>SET SQL_LOW_PRIORITY_UPDATES=#</code> didn't work. </li>
  <li>Password wasn't updated correctly if privileges didn't change on: <code>GRANT ... 
    IDENTIFIED BY</code> </li>
  <li>Fixed range optimizer bug in <code>SELECT * FROM table_name WHERE key_part1 &gt;= const 
    AND (key_part2 = const OR key_part2 = const)</code> </li>
  <li>Fixed bug in compression key handling in ISAM. </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.25" name="News-3.22.25">D.2.4 Changes in release 
3.22.25</a></h3>

<ul>
  <li>Fixed some small problems with the installation. </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.24" name="News-3.22.24">D.2.5 Changes in release 
3.22.24</a></h3>

<ul>
  <li><code>DATA</code> is not a reserved word anymore. </li>
  <li>Fixed optimizer bug with tables with only one row. </li>
  <li>Fixed bug when using <code>LOCK TABLES table_name READ; FLUSH TABLES;</code> </li>
  <li>Applied some patches for HP-UX. </li>
  <li><code>isamchk</code> should now work on Win32. </li>
  <li>Changed <tt>`configure'</tt> to not use big file handling on Linux as this crashes some 
    RedHat 6.0 systems </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.23" name="News-3.22.23">D.2.6 Changes in release 
3.22.23</a></h3>

<ul>
  <li>Upgraded to use Autoconf 2.13, Automake 1.4 and <code>libtool</code> 1.3.2. </li>
  <li>Better support for SCO in <code>configure</code>. </li>
  <li>Added option <code>--defaults-file=###</code> to option file handling to force use of 
    only one specific option file. </li>
  <li>Extended <code>CREATE</code> syntax to ignore <code>MySQL 3.23</code> keywords. </li>
  <li>Fixed deadlock problem when using <code>INSERT DELAYED</code> on a table locked with <code>LOCK 
    TABLES</code>. </li>
  <li>Fixed deadlock problem when using <code>DROP TABLE</code> on a table that was locked by 
    another thread. </li>
  <li>Add logging of <code>GRANT/REVOKE</code> commands in the update log. </li>
  <li>Fixed <code>isamchk</code> to detect a new error condition. </li>
  <li>Fixed bug in <code>NATURAL LEFT JOIN</code>. </li>
</ul>

<h3><a href="manual_toc.html#News-3.22.22" name="News-3.22.22">D.2.7 Changes in release 
3.22.22</a></h3>