Functionality added or changed:
          Added mysql_set_character_set() C API
          function for setting the default character set of the current
          connection. This allows clients to affect the character set
          used by mysql_real_escape_string(). (Bug#8317)
        
          The behaviour of the Last_query_cost system
          variable has been changed. The default value is now 0 (rather
          than -1) and it now has session-level scope (rather than being
          global). See Sección 5.3.4, “Variables de estado del servidor” for
          additional information.
        
          All characters occuring on the same line following the
          DELIMITER keyword will be set as delimiter.
          For example, DELIMITER :; will set
          :; as the delimiter. This behavior is now
          consistent between MySQL 5.1 and MySQL 5.0. (Bug#9879)
        
          The table, type, and
          rows columns of EXPLAIN
          output can now be NULL. This is required
          for using EXPLAIN on
          SELECT queries that use no tables (i.e.
          EXPLAIN SELECT 1). (Bug#9899)
        
          Placeholders now can be used for LIMIT in
          prepared statements. (Bug#7306)
        
          SHOW BINARY LOGS now displays a
          File_size column that indicates the size of
          each file.
        
          The --delayed-insert option for
          mysqldump has been disabled to avoid
          causing problems with storage engines that do not support
          INSERT DELAYED. (Bug#7815)
        
          Improved the optimizer to be able to use indexes for
          expressions of the form
          indexed_col NOT IN
          (val1,
          val2, ...)indexed_col NOT BETWEEN
          val1 AND
          val2
          Removed mysqlshutdown.exe and
          mysqlwatch.exe from the Windows “No
          Installer” distribution (they had already been removed
          from the “With Installer” distribution before).
          Removed those programs from the source distribution.
        
          Removed WinMySQLAdmin from the source
          distribution and from the “No Installer” Windows
          distribution (it had already been removed from the “With
          Installer” distribution before).
        
          InnoDB: In stored procedures and functions,
          InnoDB no longer takes full explicit table
          locks for every involved table. Only `intention' locks are
          taken, similar to those in the execution of an ordinary SQL
          statement. This greatly reduces the number of deadlocks.
        
Bugs fixed:
          Security update: A user with
          limited privileges could obtain information about the
          privileges of other users by querying objects in the
          INFORMATION_SCHEMA database for which that
          user did not have the requisite privileges. (Bug#10964)
        
Triggers with dropped functions caused crashes. (Bug#5893)
          Failure of a BEFORE trigger did not prevent
          the triggering statement from performing its operation on the
          row for which the trigger error occurred. Now the triggering
          statement fails as described in
          Sección 20.3, “Utilización de disparadores”. (Bug#10902)
        
          Issuing a write lock for a table from one client prevented
          other clients from accessing the table's metadata. For
          example, if one client issued a LOCK TABLES
          , then a second client attempting to execute a
          mydb.mytable
          WRITEUSE  would
          hang. (Bug#9998)
        mydb;
          The LAST_DAY() failed to return
          NULL when supplied with an invalid
          argument. See Sección 12.5, “Funciones de fecha y hora”. (Bug#10568)
        
          The functions COALESCE(),
          IF(), and IFNULL()
          performed incorrect conversions of their arguments. (Bug#9939)
        
          The TIME_FORMAT() function returned
          incorrect results with some format specifiers. See
          Sección 12.5, “Funciones de fecha y hora”. (Bug#10590)
        
          Dropping stored routines when the MySQL server had been
          started with --skip-grant-tables generated
          extraneous warnings. (Bug#9993)
        
          A problem with the my_global.h file
          caused compilation of MySQL to fail on single-processor Linux
          systems running 2.6 kernels. (Bug#10364)
        
The ucs2_turkish_ci collation failed with upper('i'). UPPER/LOWER now can return a string with different length. (Bug#8610)
OPTIMIZE of InnoDB table does not return 'Table is full' if out of tablespace. (Bug#8135)
GROUP BY queries with ROLLUP returned wrong results for expressions containing group by columns. (Bug#7894)
          Fixed bug in FIELD() function where value
          list contains NULL. (Bug#10944)
        
          Corrected a problem where an incorrect column type was
          returned in the result set metadata when using a prepared
          SELECT DISTINCT statement to select from a
          view. (Bug#11111)
        
          Fixed bug in the MySQL Instance manager that caused the
          version to always be unknown when
          SHOW INSTANCE STATUS was issued. (Bug#10229)
        
          Using ORDER BY to sort the results of an
          IF() that contained a
          FROM_UNIXTIME() expression returned
          incorrect results due to integer overflow. (Bug#9669)
        
          Fixed a server crash resulting from accessing
          InnoDB tables within stored functions. This
          is handled by prohibiting statements that do an explicit or
          explicit commit or rollback within stored functions or
          triggers. (Bug#10015)
        
          Fixed a server crash resulting from the second invocation of a
          stored procedure that selected from a view defined as a join
          that used ON in the join conditions. (Bug#6866)
        
          Using ALTER TABLE for a table that had a
          trigger caused a crash when executing a statement that
          activated the trigger, and also a crash later with
          USE  for
          the database containing the table. (Bug#5894)
        db_name
          Fixed a server crash resulting from an attempt to allocate too
          much memory when GROUP BY
           and
          blob_colCOUNT(DISTINCT) were used. (Bug#11088)
        
Fixed a portability problem for compiling on Windows with Visual Studio 6. (Bug#11153)
          The incorrect sequence of statements HANDLER
           without a
          preceding tbl_name READ
          index_name NEXTHANDLER  for an
          tbl_name
          READ index_name =
          (value_list)InnoDB table resulted in a server crash
          rather than an error. (Bug#5373)
        
          On Windows, with lower_case_table_names set
          to 2, using ALTER TABLE to alter a
          MEMORY or InnoDB table
          that had a mixed-case name also improperly changed the name to
          lowercase. (Bug#9660)
        
The server timed out SSL connections too quickly on Windows. (Bug#8572)
          Executing LOAD INDEX INTO CACHE for a table
          while other threads where selecting from the table caused a
          deadlock. (Bug#10602)
        
          Fixed a server crash resulting from CREATE TABLE ...
          SELECT that selected from a table being altered by
          ALTER TABLE. (Bug#10224)
        
          The FEDERATED storage engine properly
          handled outer joins, but not inner joins. (Bug#10848)
        
          Consistently report INFORMATION_SCHEMA
          table names in uppercase in SHOW TABLE
          STATUS output. (Bug#10059)
        
          Fixed a failure of WITH ROLLUP to sum
          values properly. (Bug#10982)
        
          Triggers were not being activated for multiple-table
          UPDATE or DELETE
          statements. (Bug#5860)
        
          INSERT BEFORE triggers were not being
          activated for INSERT ... SELECT statements.
          (Bug#6812)
        
          INSERT BEFORE triggers were not being
          activated for implicit inserts (LOAD DATA).
          (Bug#8755)
        
          If a stored function contained a FLUSH
          statement, the function crashed when invoked.
          FLUSH now is disallowed within stored
          functions. (Bug#8409)
        
          Multiple-row REPLACE could fail on a
          duplicate-key error when having one
          AUTO_INCREMENT key and one unique key. (Bug#11080)
        
          Fixed a server crash resulting from invalid string pointer
          when inserting into the mysql.host table.
          (Bug#10181)
        
          Multiple-table DELETE did always delete on
          the fly from the first table that was to be deleted from. In
          some cases, when using many tables and it was necessary to
          access the same row twice in the first table, we could miss
          some rows-to-be-deleted from other tables. This is now fixed.
        
          The mysql_next_result() function could hang
          if you were executing many statements in a
          mysql_real_query() call and one of those
          statements raised an error. (Bug#9992)
        
          The combination of COUNT(),
          DISTINCT, and CONCAT()
          sometimes triggered a memory deallocation bug on Windows
          resulting in a server crash. (Bug#9593)
        
          InnoDB: Do very fast shutdown only if
          innodb_fast_shutdown=2, but wait for
          threads to exit and release allocated memory if
          innodb_fast_shutdown=1. Starting with
          MySQL/InnoDB 5.0.5, InnoDB would do brutal shutdown also when
          innodb_fast_shutdown=1. (Bug#9673)
        
          InnoDB: Fixed InnoDB: Error:
          stored_select_lock_type is 0 inside ::start_stmt()!
          in a stored procedure call if
          innodb_locks_unsafe_for_binlog was set in
          my.cnf. (Bug#10746)
        
          InnoDB: Fixed a duplicate key error that
          occurred with REPLACE in a table with an
          AUTO-INC column. (Bug#11005)
        
          Fixed that MySQL would pass a wrong key length to storage
          engines in MIN(). This could cause warnings
          InnoDB: Warning: using a partial-field key prefix in
          search. in the .err log. (Bug#11039)
        
          Fixed a server crash for INSERT or
          UPDATE when the WHERE
          clause contained a correlated subquery that referred to a
          column of the table being modified. (Bug#6384)
        
          Fixed a problem causing an incorrect result for columns that
          include an aggregate function as part of an expression when
          WITH ROLLUP is added to GROUP
          BY. (Bug#7914)
        
          Fixed a problem with returning an incorrect result from a view
          that selected a COALESCE() expression from
          the result of an outer join. (Bug#9938)
        
          MySQL was adding a DEFAULT clause to
          ENUM columns that included no explicit
          DEFAULT and were defined as NOT
          NULL. (This is supposed to happen only for columns
          that are NULL.) (Bug#6267)
        
          Corrected inappropriate error messages that were displayed
          when attempting to set the read-only
          warning_count and
          error_count system variables. (Bug#10339)
        
Ésta es una traducción del manual de referencia de MySQL, que puede encontrarse en dev.mysql.com. El manual de referencia original de MySQL está escrito en inglés, y esta traducción no necesariamente está tan actualizada como la versión original. Para cualquier sugerencia sobre la traducción y para señalar errores de cualquier tipo, no dude en dirigirse a mysql-es@vespito.com.

