COLUMNS

The COLUMNS view contains information about columns in tables.

Column	Description
TABLE_CATALOG	The catalog where the table containing the column resides. This value is always def.
TABLE_SCHEMA	The schema (database) where the table containing the column resides.
TABLE_NAME	The name of the table containing the column.
COLUMN_NAME	The name of the column.
ORDINAL_POSITION	The position of the column within the table. Used for ordering, as SELECT from COLUMNS doesn’t automatically order rows.
COLUMN_DEFAULT	The default value for the column, or NULL if no default is set.
IS_NULLABLE	Indicates whether NULL values are allowed in the column: YES if they are, NO if not.
DATA_TYPE	The column’s data type name without any additional details.
CHARACTER_MAXIMUM_LENGTH	For string columns, the maximum length in characters.
CHARACTER_OCTET_LENGTH	For string columns, the maximum length in bytes.
NUMERIC_PRECISION	For numeric columns, the numeric precision.
NUMERIC_SCALE	For numeric columns, the numeric scale.
DATETIME_PRECISION	For temporal columns, the fractional seconds precision.
CHARACTER_SET_NAME	For character columns, the character set name.
COLLATION_NAME	For character columns, the collation name.
COLUMN_TYPE	The column’s data type, including any additional attributes such as length or precision.
COLUMN_KEY	Indicates whether the column is indexed. Possible values: PRI – The column is a primary key or part of a composite primary key. UNI – The column is the first column of a unique index. MUL – The column is the first column of a nonunique index that permits multiple occurrences of the same value. Empty – The column isn’t indexed or is indexed as a secondary column in a nonunique, multi-column index.
EXTRA	Additional information about the column.
PRIVILEGES	The privileges granted on the column.
COLUMN_COMMENT	The comment included in the column definition.
GENERATION_EXPRESSION	For generated columns, the expression used to compute values. Empty for non-generated columns.
SRS_ID	For spatial columns, the column’s SRID (spatial reference system identifier). NULL for nonspatial columns or spatial columns without an SRID attribute.

Column information is also available from the SHOW COLUMNS statement.

Information about generated invisible primary key (GIPK) columns is included in the INFORMATION_SCHEMA.COLUMNS view by default. You can hide these columns by setting the show_gipk_in_create_table_and_information_schema system variable to OFF.

For more information, see the MySQL documentation: The INFORMATION_SCHEMA COLUMNS Table.