To facilitate the use of code written for SQL implementations from other vendors, MySQL maps data types as shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL:
| Other Vendor Type | MySQL Type |
BOOL, |
TINYINT
|
BOOLEAN
|
TINYINT
|
CHAR VARYING(M) |
VARCHAR(M) |
DEC
|
DECIMAL
|
FIXED
|
DECIMAL
|
FLOAT4
|
FLOAT
|
FLOAT8
|
DOUBLE
|
INT1
|
TINYINT
|
INT2
|
SMALLINT
|
INT3
|
MEDIUMINT
|
INT4
|
INT
|
INT8
|
BIGINT
|
LONG VARBINARY
|
MEDIUMBLOB
|
LONG VARCHAR
|
MEDIUMTEXT
|
LONG
|
MEDIUMTEXT
|
MIDDLEINT
|
MEDIUMINT
|
NUMERIC
|
DECIMAL
|
Data type mapping occurs at table creation time, after which the
original type specifications are discarded. If you create a table
with types used by other vendors and then issue a
DESCRIBE tbl_name
statement, MySQL reports the table structure using the equivalent
MySQL types. For example:
mysql>CREATE TABLE t (a BOOL, b FLOAT8, c LONG VARCHAR, d NUMERIC);Query OK, 0 rows affected (0.00 sec) mysql>DESCRIBE t;+-------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------+------+-----+---------+-------+ | a | tinyint(1) | YES | | NULL | | | b | double | YES | | NULL | | | c | mediumtext | YES | | NULL | | | d | decimal(10,0) | YES | | NULL | | +-------+---------------+------+-----+---------+-------+ 4 rows in set (0.01 sec)