Official document address: 11.9 Using Data Types from Other Database Engines
In order to facilitate the use of codes written according to other vendors' SQL implementations, MySQL maps the data types shown in the following table. These mappings make it easier to import table definitions from other database systems into MySQL.
| Other supplier types | MySQL type |
|---|---|
| BOOL | TINYINT |
| BOOLEAN | TINYINT |
| CHARACTER VARYING(M) | VARCHAR(M) |
| 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 is performed when the table is created. After the table is created, the original type specification will be discarded. If you create a table with a type used by other vendors, and then issue a DESCRIBE tbl_namestatement, MySQL will use the corresponding MySQL type to report the table structure. E.g:
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)