MySQL Bugs: #36335: Incorrect syntax description for DECIMAL/NUMERIC column definitions

Bug #36335	Incorrect syntax description for DECIMAL/NUMERIC column definitions
Submitted:	25 Apr 2008 8:49	Modified:	25 Apr 2008 13:59
Reporter:	Kay Roepke	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:	4.1+	OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
In http://dev.mysql.com/doc/refman/4.1/en/create-table.html the syntax description for both the DECIMAL and NUMERIC types is incorrect:

It suggests that the "length,decimals" portion is required, but in fact it is optional:
  | DECIMAL(length,decimals) [UNSIGNED] [ZEROFILL]
  | NUMERIC(length,decimals) [UNSIGNED] [ZEROFILL]

How to repeat:
According to the docs the statement:
create table test.foo (a DECIMAL, b NUMERIC);

should lead to a syntax error.

Suggested fix:
Change the respective descriptions to:

  | DECIMAL[(length,decimals)] [UNSIGNED] [ZEROFILL]
  | NUMERIC[(length,decimals)] [UNSIGNED] [ZEROFILL]

and document the default values for length and decimals.

I forgot to mention that this problem is present in all versions of the docs.

Thank you for a problem report.

Please note that this problem also extends to the two following types:
CHAR, BINARY

VARCHAR and VARBINARY are not affected.

mysql> create table test.char(a char);
mysql> show create table test.char\G
*************************** 1. row ***************************
       Table: char
Create Table: CREATE TABLE `char` (
  `a` char(1) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

mysql> create table test.binary(a binary);
mysql> show create table test.binary\G
*************************** 1. row ***************************
       Table: binary
Create Table: CREATE TABLE `binary` (
  `a` binary(1) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

This page doesn't exactly track the exact syntax as specified in the data types chapter. As the page says:

"
data_type represents the data type in a column definition. spatial_type represents a spatial data type. The data type syntax shown is representative only. For a full description of the syntax available for specifying column data types, as well as information about the properties of each type, see Chapter 10, Data Types, and Chapter 16, Spatial Extensions.
"

However, it does appear that the DECIMAL/NUMERIC syntax is incorrect *everywhere* -- even if M is specified, D is optional. That needs to be fixed.

Sorry, the DECIMAL/NUMERIC syntax is correct in the data types chapter.

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.