Columns that are part of a PRIMARY KEY are made NOT NULL even if not declared that way.作为PRIMARY KEY一部分的列即使未以这种方式声明，也将被设置为NOT NULL。

Trailing spaces are automatically deleted from ENUM and SET member values when the table is created.创建表时，将自动从ENUM和SET成员值中删除尾随空格。

MySQL maps certain data types used by other SQL database vendors to MySQL types. MySQL将其他SQL数据库供应商使用的某些数据类型映射到MySQL类型。See Section 11.9, “Using Data Types from Other Database Engines”.请参阅第11.9节，“使用来自其他数据库引擎的数据类型”。

If you include a USING clause to specify an index type that is not permitted for a given storage engine, but there is another index type available that the engine can use without affecting query results, the engine uses the available type.如果包含USING子句以指定给定存储引擎不允许的索引类型，但引擎可以使用另一种索引类型而不影响查询结果，则引擎将使用该可用类型。

If strict SQL mode is not enabled, a VARCHAR column with a length specification greater than 65535 is converted to TEXT, and a VARBINARY column with a length specification greater than 65535 is converted to BLOB. 如果未启用严格SQL模式，则长度规格大于65535的VARCHAR列将转换为文本，长度规格大于65535的VARBINAL列将转换为BLOB。Otherwise, an error occurs in either of these cases.否则，在这两种情况下都会发生错误。

Specifying the CHARACTER SET binary attribute for a character data type causes the column to be created as the corresponding binary data type: CHAR becomes BINARY, VARCHAR becomes VARBINARY, and TEXT becomes BLOB. 为字符数据类型指CHARACTER SET binary属性会导致将列创建为相应的二进制数据类型：CHAR变为BINARY，VARCHAR变为VARBINARY，TEXT变为BLOB。For the ENUM and SET data types, this does not occur; they are created as declared. 对于ENUM和SET数据类型，不会发生这种情况；它们是按声明的方式创建的。Suppose that you specify a table using this definition:假设使用此定义指定一个表：

CREATE TABLE t
(
  c1 VARCHAR(10) CHARACTER SET binary,
  c2 TEXT CHARACTER SET binary,
  c3 ENUM('a','b','c') CHARACTER SET binary
);

The resulting table has this definition:

CREATE TABLE t
(
  c1 VARBINARY(10),
  c2 BLOB,
  c3 ENUM('a','b','c') CHARACTER SET binary
);