--------------------------------+
| CREATE OR REPLACE FUNCTION f1 (a INT)   | User defined exceptions.          |
| RETURN INT AS e1 EXCEPTION...           | MDEV-10587                        |
+-----------------------------------------+-----------------------------------+

BEGIN Blocks
------------

+-----------------------------------------+-----------------------------------+
| Oracle syntax                           | Description                       |
+-----------------------------------------+-----------------------------------+
| BEGIN to start a block                  | MariaDB uses BEGIN NOT ATOMIC     |
|                                         | for anyonymous blocks. MDEV-10655 |
+-----------------------------------------+-----------------------------------+
| DECLARE is used before BEGIN            | DECLARE a INT; b VARCHAR(10);     |
|                                         | BEGIN v:= 10; END;                |
+-----------------------------------------+-----------------------------------+
| WHEN DUP_VAL_ON_INDEX THEN NULL ;       | Do not require BEGIN..END in      |
| NULL; WHEN OTHERS THEN NULL             | multi-statement exception         |
|                                         | handlers in THEN clause.          |
|                                         | MDEV-12088                        |
+-----------------------------------------+-----------------------------------+

Simple Syntax Compatibility
---------------------------

+------------------------------+-----------------+--------------------------+
| Oracle syntax                | Version         | Description              |
+------------------------------+-----------------+--------------------------+
| ELSIF                        | 10.3            | ANSI uses ELSEIF         |
+------------------------------+-----------------+--------------------------+
| SELECT UNIQUE                | 10.3            | Same as SELECT           |
|                              |                 | DISTINCT. MDEV-12086     |
+------------------------------+-----------------+--------------------------+
| TRUNCATE TABLE t1 [DROP      | 10.3            | DROP STORAGE and REUSE   |
| STORAGE] or [REUSE STORAGE]  |                 | STORAGE are allowed as   |
|                              |                 | optional keywords for    |
|                              |                 | TRUNCATE TABLE.          |
|                              |                 | MDEV-10588               |
+------------------------------+-----------------+--------------------------+
| Subqueries in a FROM clause  | 10.6            | SELECT * FROM (SELECT 1  |
| without an alias             |                 | FROM DUAL), (SELECT 2    |
|                              |                 | FROM DUAL)               |
+------------------------------+-----------------+--------------------------+
| UNION, EXCEPT and INTERSECT  | 10.3            | INTERSECT has higher     |
| all have the same            |                 | precedence than UNION    |
| precedence.                  |                 | and EXCEPT in            |
|                              |                 | non-Oracle modes.        |
+------------------------------+-----------------+--------------------------+
| MINUS                        | 10.6            | MINUS is a synonym for   |
|                              |                 | EXCEPT.                  |
+------------------------------+-----------------+--------------------------+

Functions
---------

+------------------------------+-----------------+--------------------------+
| Oracle syntax                | Version         | Description              |
+------------------------------+-----------------+--------------------------+
| ADD_MONTHS()                 | 10.6.1          | Added as a wrapper for   |
|                              |                 | DATE_ADD() to enhance    |
|                              |                 | Oracle compatibility.    |
|                              |                 | All modes.               |
+---------------