锁定语句 LOCK TABLES 和 UNLOCK TABLES。The locking statements LOCK TABLES and UNLOCK TABLES.

ALTER VIEW。ALTER VIEW.

LOAD DATA 和 LOAD XML。LOAD DATA and LOAD XML.

SQL 预处理语句（PREPARE、EXECUTE、DEALLOCATE PREPARE）可以在存储过程（stored procedures）中使用，但不能在存储函数（stored functions）或触发器（triggers）中使用。因此，存储函数和触发器不能使用动态 SQL（动态构建语句作为字符串然后执行的 SQL）。SQL prepared statements (PREPARE, EXECUTE, DEALLOCATE PREPARE) can be used in stored procedures, but not in stored functions or triggers. Thus, stored functions and triggers cannot use dynamic SQL (where you construct statements as strings and then execute them).

通常，SQL 预处理语句中不允许的语句，在存储程序中也不允许。有关支持作为预处理语句的语句列表，请参见 第 15.5 节，“预处理语句”。例外情况是 SIGNAL、RESIGNAL 以及 GET DIAGNOSTICS，它们不允许作为预处理语句，但在存储程序中允许使用。Generally, statements not permitted in SQL prepared statements are also not permitted in stored programs. For a list of statements supported as prepared statements, see Section 15.5, “Prepared Statements”. Exceptions are SIGNAL, RESIGNAL, and GET DIAGNOSTICS, which are not permissible as prepared statements but are permitted in stored programs.

由于局部变量只在存储程序执行期间有效，因此在存储程序中创建的预处理语句中不允许引用它们。预处理语句的作用域是当前会话，而不是存储程序，因此语句可能在程序结束后执行，届时变量将不再有效。例如，SELECT ... INTO local_var 不能作为预处理语句使用。这一限制同样适用于存储过程和函数的参数。参见 第 15.5.1 节，“PREPARE 语句”。Because local variables are in scope only during stored program execution, references to them are not permitted in prepared statements created within a stored program. Prepared statement scope is the current session, not the stored program, so the statement could be executed after the program ends, at which point the variables would no longer be in scope. For example, SELECT ... INTO local_var cannot be used as a prepared statement. This restriction also applies to stored procedure and function parameters. See Section 15.5.1, “PREPARE Statement”.

在所有存储程序（存储过程和函数、触发器以及事件）中，解析器将 BEGIN [WORK] 视为 BEGIN ... END 块的开始。Within all stored programs (stored procedures and functions, triggers, and events), the parser treats BEGIN [WORK] as the beginning of a BEGIN ... END block.

要在存储过程或事件中开始事务，请使用 START TRANSACTION。To begin a transaction within a stored procedure or event, use START TRANSACTION instead.

START TRANSACTION 不能在存储函数或触发器中使用。START TRANSACTION cannot be used within a stored function or trigger.

执行显式或隐式提交或回滚的语句。这些语句的支持不是 SQL 标准所要求的，SQL 标准规定每个数据库管理系统供应商可以自行决定是否允许它们。Statements that perform explicit or implicit commit or rollback. Support for these statements is not required by the SQL standard, which states that each DBMS vendor may decide whether to permit them.

返回结果集的语句。这包括没有 SELECT 子句的 INTO var_list 语句，以及其他语句，如 SHOW、EXPLAIN 和 CHECK TABLE。函数可以通过 SELECT ... INTO var_list 或使用游标和 FETCH 语句来处理结果集。参见 第 15.2.13.1 节，“SELECT ... INTO 语句” 和 第 15.6.6 节，“游标”。Statements that return a result set. This includes SELECT statements that do not have an INTO var_list clause and other statements such as SHOW, EXPLAIN, and CHECK TABLE. A function can process a result set either with SELECT ... INTO var_list or by using a cursor and FETCH statements. See Section 15.2.13.1, “SELECT ... INTO Statement”, and Section 15.6.6, “Cursors”.

FLUSH 语句。FLUSH statements.

存储函数不能递归使用。Stored functions cannot be used recursively.

存储函数或触发器不能修改已经被调用此函数或触发器的语句用于读取或写入的表。A stored function or trigger cannot modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger.

如果在存储函数中以不同的别名多次引用临时表，即使这些引用出现在函数中的不同语句中，也会出现 Can't reopen table: 'tbl_name' 错误。If you refer to a temporary table multiple times in a stored function under different aliases, a Can't reopen table: 'tbl_name' error occurs, even if the references occur in different statements within the function.

HANDLER ... READ 语句调用存储函数可能导致复制错误，因此不允许使用。HANDLER ... READ statements that invoke stored functions can cause replication errors and are disallowed.

触发器不会被外键操作触发。Triggers are not activated by foreign key actions.

在使用基于行的复制时，源端的语句不会激活副本上的触发器。在使用基于语句的复制时，副本上的触发器会被激活。有关更多信息，请参见第 19.5.1.36 节，“复制与触发器”。When using row-based replication, triggers on the replica are not activated by statements originating on the source. The triggers on the replica are activated when using statement-based replication. For more information, see Section 19.5.1.36, “Replication and Triggers”.

触发器中不允许使用RETURN语句，触发器不能返回值。要立即退出触发器，请使用LEAVE语句。The RETURN statement is not permitted in triggers, which cannot return a value. To exit a trigger immediately, use the LEAVE statement.

在 mysql 数据库中的表上不允许使用触发器。INFORMATION_SCHEMA 或 performance_schema 表上也不允许使用触发器。这些表实际上是视图，而视图上不允许使用触发器。Triggers are not permitted on tables in the mysql database. Nor are they permitted on INFORMATION_SCHEMA or performance_schema tables. Those tables are actually views and triggers are not permitted on views.

触发器缓存无法检测底层对象的元数据何时发生变化。如果一个触发器使用了某个表，而该表在触发器加载到缓存之后发生了变化，那么触发器将使用过时的元数据进行操作。The trigger cache does not detect when metadata of the underlying objects has changed. If a trigger uses a table and the table has changed since the trigger was loaded into the cache, the trigger operates using the outdated metadata.

局部变量优先于例程参数或表列。A local variable takes precedence over a routine parameter or table column.

例程参数优先于表列。A routine parameter takes precedence over a table column.

内部块中的局部变量优先于外部块中的局部变量。A local variable in an inner block takes precedence over a local variable in an outer block.

UNDO 处理程序UNDO handlers

FOR 循环FOR loops

事件名称不区分大小写。例如，在同一个数据库中，你不能同时拥有名为 anEvent 和 AnEvent 的两个事件。Event names are handled in case-insensitive fashion. For example, you cannot have two events in the same database with the names anEvent and AnEvent.

不能从存储程序中创建事件。如果事件名称是通过变量指定的，则不能从存储程序中修改或删除事件。事件也不能创建、修改或删除存储例程或触发器。An event may not be created from within a stored program. An event may not be altered, or dropped from within a stored program, if the event name is specified by means of a variable. An event also may not create, alter, or drop stored routines or triggers.

当 LOCK TABLES 语句生效时，禁止对事件执行 DDL 语句。DDL statements on events are prohibited while a LOCK TABLES statement is in effect.

使用间隔 YEAR、QUARTER、MONTH 和 YEAR_MONTH 的事件时间以月为单位解析；使用任何其他间隔的事件以秒为单位解析。无法保证在同一秒计划执行的事件按特定顺序执行。此外——由于四舍五入、线程应用程序的特性以及创建事件和发出执行信号需要非零长度时间——事件可能延迟 1 到 2 秒。然而，Information Schema EVENTS 表的 LAST_EXECUTED 列显示的时间始终与实际事件执行时间的误差在一秒以内。（另见 Bug #16522。）Event timings using the intervals YEAR, QUARTER, MONTH, and YEAR_MONTH are resolved in months; those using any other interval are resolved in seconds. There is no way to cause events scheduled to occur at the same second to execute in a given order. In addition—due to rounding, the nature of threaded applications, and the fact that a nonzero length of time is required to create events and to signal their execution—events may be delayed by as much as 1 or 2 seconds. However, the time shown in the Information Schema EVENTS table's LAST_EXECUTED column is always accurate to within one second of the actual event execution time. (See also Bug #16522.)

事件主体中包含的每条语句的每次执行都发生在一个新的连接中；因此，这些语句不会影响服务器上特定用户会话中的语句计数，例如通过SHOW STATUS显示的Com_select和Com_insert。然而，这些计数确实会在全局范围内更新。(Bug #16422)Each execution of the statements contained in the body of an event takes place in a new connection; thus, these statements have no effect in a given user session on the server's statement counts such as Com_select and Com_insert that are displayed by SHOW STATUS. However, such counts are updated in the global scope. (Bug #16422)

事件不支持晚于 Unix 纪元结束的时间；大约是 2038 年年初。事件调度程序明确不允许此类日期。(Bug #16396)Events do not support times later than the end of the Unix Epoch; this is approximately the beginning of the year 2038. Such dates are specifically not permitted by the Event Scheduler. (Bug #16396)

在 CREATE EVENT 和 ALTER EVENT 语句的 ON SCHEDULE 子句中，不支持对存储函数、可加载函数和表的引用。不允许使用此类引用。（有关更多信息，请参见 Bug #22830。）References to stored functions, loadable functions, and tables in the ON SCHEDULE clauses of CREATE EVENT and ALTER EVENT statements are not supported. These sorts of references are not permitted. (See Bug #22830 for more information.)