MySQL Bugs: #38123: Set clause in update also accepts DEFAULT

Bug #38123	Set clause in update also accepts DEFAULT
Submitted:	15 Jul 2008 7:56	Modified:	15 Jul 2008 17:25
Reporter:	Kay Roepke	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	5.1	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
The documentation at http://dev.mysql.com/doc/refman/5.1/en/update.html states that the SET clause for the UPDATE statement contains a column name and expression pair.
In fact you can use either an expression or DEFAULT (like with INSERT and REPLACE)

How to repeat:
Execute the following statements to see that it works.

CREATE TABLE `uptest` (
  `a` int(11) NOT NULL DEFAULT '0',
  `b` int(11) NOT NULL DEFAULT '42',
  PRIMARY KEY (`a`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1

mysql> insert into uptest set a=0, b=0;
Query OK, 1 row affected (0.01 sec)

mysql> update uptest set a=1, b=DEFAULT where a=0;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from uptest;
+---+----+
| a | b  |
+---+----+
| 1 | 42 | 
+---+----+
1 row in set (0.00 sec)

Suggested fix:
Change the syntax description expr1|DEFAULT in the UPDATE reference.

Note that this behavior is different to using the DEFAULT() function, it is a syntax element at this point.

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.