TABLE_ID

表示与该列关联的表的标识符；其值与 INNODB_TABLES.TABLE_ID 相同。An identifier representing the table associated with the column; the same value as INNODB_TABLES.TABLE_ID.

NAMENAME

列的名称。这些名称可以是大写或小写，具体取决于lower_case_table_names 设置。列没有特殊的系统保留名称。The name of the column. These names can be uppercase or lowercase depending on the lower_case_table_names setting. There are no special system-reserved names for columns.

POS

列在表中的顺序位置，从 0 开始，依次递增。当删除一个列时，其余列会重新排序，使序列没有空隙。虚拟生成列的POS值编码了列的序列号和顺序位置。更多信息，请参见第 28.4.29 节，“INFORMATION_SCHEMA INNODB_VIRTUAL 表”中POS列的描述。The ordinal position of the column within the table, starting from 0 and incrementing sequentially. When a column is dropped, the remaining columns are reordered so that the sequence has no gaps. The POS value for a virtual generated column encodes the column sequence number and ordinal position of the column. For more information, see the POS column description in Section 28.4.29, “The INFORMATION_SCHEMA INNODB_VIRTUAL Table”.

MTYPE

代表“主类型”。列类型的数字标识符。1 = VARCHAR，2 = CHAR，3 = FIXBINARY，4 = BINARY，5 = BLOB，6 = INT，7 = SYS_CHILD，8 = SYS，9 = FLOAT，10 = DOUBLE，11 = DECIMAL，12 = VARMYSQL，13 = MYSQL，14 = GEOMETRY。Stands for “main type”. A numeric identifier for the column type. 1 = VARCHAR, 2 = CHAR, 3 = FIXBINARY, 4 = BINARY, 5 = BLOB, 6 = INT, 7 = SYS_CHILD, 8 = SYS, 9 = FLOAT, 10 = DOUBLE, 11 = DECIMAL, 12 = VARMYSQL, 13 = MYSQL, 14 = GEOMETRY.

PRTYPE

InnoDB “精确类型”，一个二进制值，其中的位表示 MySQL 数据类型、字符集编码和可空性。The InnoDB “precise type”, a binary value with bits representing MySQL data type, character set code, and nullability.

LEN

列长度，例如 INT 为 4，BIGINT 为 8。对于多字节字符集中的字符列，这个长度值是表示类似 VARCHAR(N) 定义所需的最大字节数；也就是说，根据字符编码，它可能是 2*N、3*N 等等。The column length, for example 4 for INT and 8 for BIGINT. For character columns in multibyte character sets, this length value is the maximum length in bytes needed to represent a definition such as VARCHAR(N); that is, it might be 2*N, 3*N, and so on depending on the character encoding.

HAS_DEFAULT

一个布尔值，用于指示一个使用 ALTER TABLE ... ADD COLUMN 并带有 ALGORITHM=INSTANT 立即添加的列是否有默认值。所有立即添加的列都有默认值，因此该列用于指示该列是否是立即添加的。A boolean value indicating whether a column that was added instantly using ALTER TABLE ... ADD COLUMN with ALGORITHM=INSTANT has a default value. All columns added instantly have a default value, which makes this column an indicator of whether the column was added instantly.

DEFAULT_VALUE

使用 ALTER TABLE ... ADD COLUMN 并带 ALGORITHM=INSTANT 即时添加列的初始默认值。如果默认值为 NULL 或未指定，则该列显示 NULL。显式指定的非 NULL 默认值以内部二进制格式显示。随后的列默认值修改不会更改该列报告的值。The initial default value of a column that was added instantly using ALTER TABLE ... ADD COLUMN with ALGORITHM=INSTANT. If the default value is NULL or was not specified, this column reports NULL. An explicitly specified non-NULL default value is shown in an internal binary format. Subsequent modifications of the column default value do not change the value reported by this column.

你必须拥有 PROCESS 权限才能查询此表。You must have the PROCESS privilege to query this table.

使用 INFORMATION_SCHEMA COLUMNS 表或 SHOW COLUMNS 语句查看关于此表列的更多信息，包括数据类型和默认值。Use the INFORMATION_SCHEMA COLUMNS table or the SHOW COLUMNS statement to view additional information about the columns of this table, including data types and default values.