ALTER TABLE `ecommerce`.`users` ADD id INT AUTO_INCREMENT;
This is my SQL code. When I run it I get
#1060 duplicate column name 'id'
Kindly help
The error means that there is already a column with the name id in your table, so you can't add another one with the same name.
What you can do is modify the existing column's attributes:
ALTER TABLE `ecommerce`.`users` MODIFY COLUMN id INT AUTO_INCREMENT;
If the existing column is not already set as UNIQUE or PRIMARY KEY you must also set one of these in the ALTER statement:
ALTER TABLE `ecommerce`.`users` MODIFY COLUMN id INT AUTO_INCREMENT PRIMARY KEY;
You can update existing column as below
ALTER TABLE `ecommerce`.`users` MODIFY COLUMN id INT auto_increment
I wonder how to add new column ( set as primary key and set default value) in existing table ? I tried
ALTER TABLE table_name ADD ( column_name VARCHAR (10));
ALTER TABLE table_name ALTER COLUMN column_name SET DEFAULT 'value1';
ALTER TABLE table_name ADD PRIMARY KEY(column_name);
>> ERROR 1138 (22004): Invalid use of NULL value
I saw couple posts but it requires to delete all existing data in the table which I don't want to. Is there other way to add new column as primary key without delete data in table?
My current table:
My new table that I want to create:
Thanks
Doing this gives ERROR since whenever you add a new column in a table which already has 1 or more rows then the new column will get NULL values in all of its tuples which is contradictory to the rule which says PRIMARY KEY CAN NOT CONTAIN NULL.
Also, if you provide DEFAULT value, then also duplicate entries aren't allowed in the primary key!
So just by adding a new column in a non-empty table by giving default and declaring it primary key at the same time will not work.
Now here comes AUTO_INCREMENT to rescue, add column by incrementing and declarig it as primary key:
ALTER TABLE table_name ADD COLUMN new_column INT AUTO_INCREMENT PRIMARY
KEY ;
This works fine now...
Thanks for asking.
Your column might have Null values in it, and also try dropping the primary key constraint first if there is any.
try this DDL:
ALTER TABLE table_name ADD ( column_name VARCHAR (10) SET DEFAULT 'value1');
ALTER TABLE table_name ADD PRIMARY KEY(column_name);
Your column might have null values
If your table doesn't have a primary key and would like to add a new column and make it as a primary key, use the below query and use auto increment so it will be unique
ALTER TABLE old_table ADD pk_column INT AUTO_INCREMENT PRIMARY KEY;
I am finding some difficulties trying to modify a MySql table with an error.
This table have an id field that is setted as PK. The problem is that when this table was created this field was not setted as auto increment.
I tried also to remove this field and add it again setting it as autoincrement but I can't do it because this is used in other tables as FK, infact I am obtaining this error message:
#HY000Cannot drop column 'id': needed in a foreign key constraint 'FK_LivestockMessageDetails_LivestockMessage' of table 'digital_services_DB.LivestockMessageDetails'
while executing:
ALTER TABLE LivestockMessage
DROP `id`,
ENGINE=InnoDB ROW_FORMAT=DYNAMIC DEFAULT CHARACTER SET latin1 COLLATE latin1_swedish_ci
I know that I can remove the FK, remove my id field and create it again as auto increment.
But how can I modify my table setting it as auto increment wothout do all this procedure?
Alter the table and modify the column to include the AUTO_INCREMENT option?
ALTER TABLE LivestockMessage MODIFY COLUMN id INT AUTO_INCREMENT;
(The table will retain its PRIMARY KEY constraint on id.)
http://sqlfiddle.com/#!9/6a1697/3
Try to add the auto increment option :
ALTER TABLE `your_db`.`LivestockMessage`
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ;
Or using MySQL Work Bench select the AI option on the column configuration :
I'm relatively new to MySQL.
So, let's say I make a table and my table utilizes an "id" column to keep track of a unique identification number. However, when creating my table, I neglected to specify that I wanted the column to be auto-incremented, not null, and the primary key of the table. What MySQL statement can I use to alter the information of this table so that it is correct for what I want? I have tried some variations of the "ALTER TABLE" command, don't seem to understand the syntax.
use this:
ALTER TABLE `table_name`
MODIFY COLUMN `id` BIGINT( 20 ) PRIMARY KEY AUTO_INCREMENT
ALTER TABLE `yourTable`
CHANGE COLUMN `id` `id` INT(10) NOT NULL AUTO_INCREMENT FIRST,
ADD PRIMARY KEY (`id`);
How do I add auto_increment to an existing column of a MySQL table?
I think you want to MODIFY the column as described for the ALTER TABLE command. It might be something like this:
ALTER TABLE users MODIFY id INTEGER NOT NULL AUTO_INCREMENT;
Before running above ensure that id column has a Primary index.
Method to add AUTO_INCREMENT to a table with data while avoiding “Duplicate entry” error:
Make a copy of the table with the data using INSERT SELECT:
CREATE TABLE backupTable LIKE originalTable;
INSERT backupTable SELECT * FROM originalTable;
Delete data from originalTable (to remove duplicate entries):
TRUNCATE TABLE originalTable;
To add AUTO_INCREMENT and PRIMARY KEY
ALTER TABLE originalTable ADD id INT PRIMARY KEY AUTO_INCREMENT;
Copy data back to originalTable (do not include the newly created column (id), since it will be automatically populated)
INSERT originalTable (col1, col2, col3)
SELECT col1, col2,col3
FROM backupTable;
Delete backupTable:
DROP TABLE backupTable;
More on the duplication of tables using CREATE LIKE:
Duplicating a MySQL table, indices, and data
Alter table table_name modify column_name datatype(length) AUTO_INCREMENT PRIMARY KEY
You should add primary key to auto increment, otherwise you got error in mysql.
Simply just add auto_increment Constraint In column or MODIFY COLUMN :-
ALTER TABLE `emp` MODIFY COLUMN `id` INT NOT NULL UNIQUE AUTO_INCREMENT FIRST;
Or add a column first then change column as -
1. Alter TABLE `emp` ADD COLUMN `id`;
2. ALTER TABLE `emp` CHANGE COLUMN `id` `Emp_id` INT NOT NULL UNIQUE AUTO_INCREMENT FIRST;
This worked for me in case you want to change the AUTO_INCREMENT-attribute for a not-empty-table:
1.)Exported the whole table as .sql file
2.)Deleted the table after export
2.)Did needed change in CREATE_TABLE command
3.)Executed the CREATE_TABLE and INSERT_INTO commands from the .sql-file
...et viola
I managed to do this with the following code:
ALTER TABLE `table_name`
CHANGE COLUMN `colum_name` `colum_name` INT(11) NOT NULL AUTO_INCREMENT FIRST;
This is the only way I could make a column auto increment.
INT(11) shows that the maximum int length is 11, you can skip it if you want.
Alter table table_name modify table_name.column_name data_type AUTO_INCREMENT;
eg:
Alter table avion modify avion.av int AUTO_INCREMENT;
if you have FK constraints and you don't want to remove the constraint from the table. use "index" instead of primary. then you will be able to alter it's type to auto increment
I had existing data in the first column and they were 0's.
First I made the first column nullable.
Then I set the data for the column to null.
Then I set the column as an index.
Then I made it a primary key with auto incrementing turned on. This is where I used another persons answer above:
ALTER TABLE `table_name` CHANGE COLUMN `colum_name` `colum_name` INT(11) NOT NULL AUTO_INCREMENT FIRST;
This Added numbers to all the rows of this table starting at one. If I ran the above code first it wasn't working because all the values were 0's. And making it an index was also required before making it auto incrementing.
Next I made the column a primary key.
This worked in my case , if you want to change the column attribute to auto-increment which is already having some data
1.GO to structure, select the column to want to change.
2.After selecting the column , choose primary key from the options below.
[1]: https://i.stack.imgur.com/r7w8f.png
3.Then change the column attribute to auto-increment using alter method
This is to alter the column adding PRIMARY key:
ALTER TABLE `schema_name`.`table_name`
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ,
ADD UNIQUE INDEX `id_UNIQUE` (`id` ASC) VISIBLE,
ADD PRIMARY KEY (`id`);
I copied it from MySQL Workbench... I got curious to see if it was possible to do it all in one command. I'm a little rusty in SQL.
If you are working in an specific schema, you don't need to specify it.
The above statement will create the index, set the column as the PRIMARY KEY as well with just one query.
KEEP IN MIND: There could not be duplicated values in the same column, if there are, the statement will fail to commit.
ALTER TABLE Table name ADD column datatype AUTO_INCREMENT,ADD primary key(column);