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#Mysql create table with autoincrement how to

This MySQL AUTO_INCREMENT example would change the next value in the AUTO_INCREMENT field (ie: next value in the sequence) to 50 for the contact_id field in the contacts table. Run the following CREATE statement to create a table named students where id field will be created with auto-increment.

#Mysql create table with autoincrement how to

Let's look at an example of how to change the starting value for the AUTO_INCREMENT column in a table in MySQL.įor example: ALTER TABLE contacts AUTO_INCREMENT = 50 start_value The next value in the sequence to assign in the AUTO_INCREMENT column. You do not need to specify the name of the column that contains the AUTO_INCREMENT value. Since a table in MySQL can only contain one AUTO_INCREMENT column, you are only required to specify the table name that contains the sequence. In MySQL, the syntax to change the starting value for an AUTO_INCREMENT column using the ALTER TABLE statement is: ALTER TABLE table_name AUTO_INCREMENT = start_value table_name The name of the table whose AUTO_INCREMENT value you wish to change. You can use the ALTER TABLE statement to change or set the next value assigned by the AUTO_INCREMENT. Now that you've created a table using the AUTO_INCREMENT attribute, how can you change the starting value for the AUTO_INCREMENT field if you don't want to start at 1?

The primary key is called contacts_pk and is set to the contact_id column.

The fourth column is called birthday which is a DATE datatype and can contain NULL values.

The third column is called first_name which is a VARCHAR datatype (maximum 25 characters in length) and can contain NULL values.

The second column is called last_name which is a VARCHAR datatype (maximum 30 characters in length) and can not contain NULL values.

It is set as an AUTO_INCREMENT field which means that it is an autonumber field (starting at 1, and incrementing by 1, unless otherwise specified.)

The first column is called contact_id which is created as an INT datatype (maximum 11 digits in length) and can not contain NULL values.

This MySQL AUTO_INCREMENT example creates a table called contacts which has 4 columns and one primary key: ( contact_id INT(11) NOT NULL AUTO_INCREMENT,ĬONSTRAINT contacts_pk PRIMARY KEY (contact_id)

Let's look at an example of how to use a sequence or the AUTO_INCREMENT attribute in MySQL.