[#MDEV-15394] DEFAULT current_timestamp() discrepancy

It was a side effect, in a way. In earlier versions, the default could be either a constant or CURRENT_TIMESTAMP.

Now it's just an expression, so the default value is printed like any expression is. See how CURRENT_TIMESTAMP is printed elsewhere:

MariaDB [test]> explain extended select CURRENT_TIMESTAMP;

+------+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra          |

+------+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+

|    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL |     NULL | No tables used |

+------+-------------+-------+------+---------------+------+---------+------+------+----------+----------------+

1 row in set, 1 warning (0.00 sec)

Note (Code 1003): select current_timestamp() AS `CURRENT_TIMESTAMP`

MariaDB [test]> create view v1 as SELECT CURRENT_TIMESTAMP; show create view v1;

Query OK, 0 rows affected (0.00 sec)

+------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+

| View | Create View                                                                                                                               | character_set_client | collation_connection |

+------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+

| v1   | CREATE ALGORITHM=UNDEFINED DEFINER=`serg`@`localhost` SQL SECURITY DEFINER VIEW `v1` AS select current_timestamp() AS `CURRENT_TIMESTAMP` | utf8                 | utf8_general_ci      |

+------+-------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+

1 row in set (0.00 sec)

Now CURRENT_TIMESTAMP is consistently printed everywhere. In earlier versions, the sequence of letters "DEFAULT CURRENT_TIMESTAMP" was hard-coded, so CURRENT_TIMESTAMP was printed differently in DEFAULT as compared to all other cases.

10.2+ Integer DEFAULT values missing quotes (MDEV-15377) [MDEV-15394] DEFAULT current_timestamp() discrepancy Created: 2018-02-23 Updated: 2018-04-15 Resolved: 2018-04-15
Status:	Closed
Project:	MariaDB Server
Component/s:	Documentation, Server
Affects Version/s:	10.2
Fix Version/s:	N/A

[MDEV-15394] DEFAULT current_timestamp() discrepancy Created: 2018-02-23 Updated: 2018-04-15 Resolved: 2018-04-15