T (:x,:y) FROM DUAL' USING 10,20   |                                   |
+-----------------------------------------+-----------------------------------+

Synonyms for Basic SQL Types
----------------------------

+--------------------------------+-------------------------------------------+
| Oracle type                    | MariaDB synonym                           |
+--------------------------------+-------------------------------------------+
| VARCHAR2                       | VARCHAR                                   |
+--------------------------------+-------------------------------------------+
| NUMBER                         | DECIMAL                                   |
+--------------------------------+-------------------------------------------+
| DATE (with time portion)       | MariaDB DATETIME                          |
+--------------------------------+-------------------------------------------+
| RAW                            | VARBINARY                                 |
+--------------------------------+-------------------------------------------+
| CLOB                           | LONGTEXT                                  |
+--------------------------------+-------------------------------------------+
| BLOB                           | LONGBLOB                                  |
+--------------------------------+-------------------------------------------+

This was implemented as part of MDEV-10343.

If one does a SHOW CREATE TABLE in ORACLE mode on a table that has a native
MariaDB DATE column, it will be displayed as mariadb_schema.date to not
conflict with the Oracle DATE type.

Packages
--------

The following syntax has been supported since MariaDB 10.3.5:

* CREATE PACKAGE
* CREATE PACKAGE BODY
* DROP PACKAGE
* DROP PACKAGE BODY
* SHOW CREATE PACKAGE
* SHOW CREATE PACKAGE BODY

NULL Handling
-------------

Oracle mode makes the following changes to NULL handling:

NULL As a Statement
-------------------

NULL can be used as a statement:

IF a=10 THEN NULL; ELSE NULL; END IF

Translating Empty String Literals to NULL
-----------------------------------------

In Oracle, empty string ('') and NULL are the same thing,

By using sql_mode=EMPTY_STRING_IS_NULL you can get a similar experience in
MariaDB:

SET sql_mode=EMPTY_STRING_IS_NULL;
SELECT '' IS NULL; -- returns TRUE
INSERT INTO t1 VALUES (''); -- inserts NULL

Concat Operator Ignores NULL
----------------------------

CONCAT() and || ignore NULL in Oracle mode. Can also be accessed outside of
ORACLE mode by using CONCAT_OPERATOR_ORACLE. MDEV-11880 and MDEV-12143.

Reserved Words
--------------

There are a number of extra reserved words in Oracle mode.

SHOW CREATE TABLE
-----------------

The SHOW CREATE TABLE statement will not display MariaDB-specific table
options, such as AUTO_INCREMENT or CHARSET, when Oracle mode is set.

URL: https://mariadb.com/kb/en/sql_modeoracle/