MySQL 'NOT NULL' Error - mysql

Question

I have question about 'NOT NULL' error. I need to make a table with variable type: 'SERIAL' and length of 7. Here is an error that SQL sends to me:
SQL query:
CREATE TABLE `table42`.`CheckOuts ` (
`CheckOutID` SERIAL( 7 ) NOT NULL
) ENGINE = MYISAM ;
The error that is returned:
#1064 - You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use
near '(7) NOT NULL) ENGINE = MyISAM' at line 1

Answer 1

I think your problem is that SERIAL isn't supported in that method for MySQL. Docs suggest you should be using AUTO_INCREMENT instead:
see: http://www.sqlines.com/mysql/auto_increment
also: What is the difference between SERIAL and AUTO_INCREMENT in mysql
These suggest you should be creating your table with the following example syntax:
create table myfriends (
id int primary key auto_increment,
frnd_name varchar(50) not null
);

Answer 2

The SERIAL type already has NOT NULL as part of its definition, so your NOT NULL declaration is redundant

Answer 3

Error is not due to NOT NULL, although SERIAL already includes NOT NULL, an error does not occur when duplicating it. The cause of the error is for the length that you try to assign (7):
mysql> DROP TABLE IF EXISTS `CheckOuts`;
Query OK, 0 rows affected (0.00 sec)
mysql> CREATE TABLE IF NOT EXISTS `CheckOuts` (
-> -- `CheckOutID` SERIAL(7) NOT NULL
-> `CheckOutID` SERIAL NOT NULL
-> ) ENGINE=MYISAM;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW CREATE TABLE `CheckOuts`\G
*************************** 1. row ***************************
Table: CheckOuts
Create Table: CREATE TABLE `CheckOuts` (
`CheckOutID` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
UNIQUE KEY `CheckOutID` (`CheckOutID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
I don't understand what you're trying to do, but if you need to assign a length, you'll need something like:
mysql> DROP TABLE IF EXISTS `CheckOuts`;
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> CREATE TABLE IF NOT EXISTS `CheckOuts` (
-> `CheckOutID` INT(7) UNSIGNED SERIAL DEFAULT VALUE
-> ) ENGINE=MYISAM;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW CREATE TABLE `CheckOuts`\G
*************************** 1. row ***************************
Table: CheckOuts
Create Table: CREATE TABLE `CheckOuts` (
`CheckOutID` int(7) unsigned NOT NULL AUTO_INCREMENT,
UNIQUE KEY `CheckOutID` (`CheckOutID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)
See documentation:
11.1.1 Numeric Type Overview
...
SERIAL is an alias for BIGINT UNSIGNED NOT NULL AUTO_INCREMENT
UNIQUE.
SERIAL DEFAULT VALUE in the definition of an integer column is an
alias for NOT NULL AUTO_INCREMENT UNIQUE.
...