Change the type of an unconstrained column

Last Updated:2026-09-04 08:14:03

This topic describes incompatibilities between MySQL databases and MySQL tenants of OceanBase Database when you change the type of an unconstrained column.

The following table describes the types to which you can change a column by executing the ALTER TABLE table_name MODIFY/CHANGE COLUMN DDL statement in a MySQL database and a MySQL tenant of OceanBase Database.

Note

In the following table, a hyphen (-) means N/A. 'All' means all types.

Column type in a MySQL database	Supported target type other than the original type	Column type in a MySQL tenant of OceanBase Database	Supported target type other than the original type
INT	All	INTEGER	BIGINT
TINYINT	All	TINYINT	INTEGER SMALLINT MEDIUMINT BIGINT BOOLEAN
SMALLINT	All	SMALLINT	INTEGER BIGINT MEDIUMINT
MEDIUMINT	All	MEDIUMINT	INTEGERBIGINT
BIGINT	All	BIGINT	-
BOOL	All	BOOLEAN	INTEGER TINYINT SMALLINT MEDIUMINT BIGINT
DECIMAL	All	DECIMAL	NUMERIC
NUMERIC	All	NUMERIC	DECIMAL
REAL	All	FLOAT	-
DOUBLE	All	DOUBLE	-
FLOAT	All	FLOAT	-
BIT	All	BIT	-
CHAR	All	CHAR	-
NCHAR	All	CHAR	-
VARCHAR	All	VARCHAR	TINYTEXT TEXT LONGTEXT MEDIUMTEXT
BINARY	All	BINARY	-
VARBINARY	All	VARBINARY	BLOB TINYBLOB MEDIUMBLOB LONGBLOB
LONG_VARBINARY	All	BLOB	-
YEAR	All	YEAR	-
DATE	All	DATE	-
TIME	All	TIME	-
TIMESTAMP	All	TIMESTAMP	-
DATETIME	All	DATETIME	-
TINYBLOB	All	TINYBLOB	BLOB LONGBLOB MEDIUMBLOB
MEDIUMBLOB	All	MEDIUMBLOB	-
BLOB	All	BLOB	-
LONGBLOB	All	LONGBLOB	-
TINYTEXT	All	TINYTEXT	TEXT LONGTEXT MEDIUMTEXT
MEDIUMTEXT	All	MEDIUMTEXT	-
TEXT	All	TEXT	-
LONGTEXT	All	LONGTEXT	-
ENUM	All	ENUM	-
SET	All	SET	-
JSON	All	JSON	-

Previous topic

Change the type of a constrained column

Last

Next topic

Change the length of a constrained column