Altering Table Information in MySQL - mysql

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`);

Related

how to change primary key column to auto increment when its a foreign key of different table in mysql

Can not alter table because animal id is foreign key in different table
ALTER TABLE 'animal' CHANGE 'animal_id' 'animal_id' INT(11) NOT NULL AUTO_INCREMENT;
Because I can't see your full code, however, I think you can try this:
ALTER TABLE 'animal' MODIFY 'animal_id INT(11) AUTO_INCREMENT;
I think you could do something similar to this response: How to update primary key. When you update the PK, I think you could do something like this response: Alter a MySQL column to be AUTO_INCREMENT.
But since this response is not best practice, if you don't need the data in the table, you could drop and then recreate the table.

Which method to add row number is faster in MySQL? [duplicate]

I have a pre-existing table, containing 'fname', 'lname', 'email', 'password' and 'ip'. But now I want an auto-increment column. However, when I enter:
ALTER TABLE users
ADD id int NOT NULL AUTO_INCREMENT
I get the following:
#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key
Any advice?:)
Try this
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT;
for an existing primary key
If you don't care whether the auto-id is used as PRIMARY KEY, you can just do
ALTER TABLE `myTable` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST;
I just did this and it worked a treat.
If you want to add AUTO_INCREMENT in an existing table, need to run following SQL command:
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key
First you have to remove the primary key of the table
ALTER TABLE nametable DROP PRIMARY KEY
and now yo can add the autoincrement ...
ALTER TABLE nametable ADD id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
Well, you must first drop the auto_increment and primary key you have and then add yours, as follows:
-- drop auto_increment capability
alter table `users` modify column id INT NOT NULL;
-- in one line, drop primary key and rebuild one
alter table `users` drop primary key, add primary key(id);
-- re add the auto_increment capability, last value is remembered
alter table `users` modify column id INT NOT NULL AUTO_INCREMENT;
If you run the following command :
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This will show you the error :
ERROR 1060 (42S21): Duplicate column name 'id'
This is because this command will try to add the new column named id to the existing table.
To modify the existing column you have to use the following command :
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This should work for changing the existing column constraint....!
Delete the primary key of a table if it exists:
ALTER TABLE `tableName` DROP PRIMARY KEY;
Adding an auto-increment column to a table :
ALTER TABLE `tableName` ADD `Column_name` INT PRIMARY KEY AUTO_INCREMENT;
Modify the column which we want to consider as the primary key:
alter table `tableName` modify column `Column_name` INT NOT NULL AUTO_INCREMENT PRIMARY KEY;
Just change the ADD to MODIFY and it will works !
Replace
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT
To
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT;
Drop the primary index from the table:
ALTER TABLE `tableName` DROP INDEX `PRIMARY`;
Then add the id column (without a primary index). I have used a big int because I am going to have lots of data but INT(11) should work just as well:
ALTER TABLE `tableName` ADD COLUMN `id` BIGINT(11) NOT NULL FIRST;
Then modify the column with auto-increment (thanks php). It needs to be a primary key:
ALTER TABLE `tableName ` MODIFY COLUMN `id` BIGINT(11) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
I have just tried this on a table of mine and it appears to have worked.
ALTER TABLE users CHANGE id int( 30 ) NOT NULL AUTO_INCREMENT
the integer parameter is based on my default sql setting
have a nice day
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key FIRST
For PostgreSQL you have to use SERIAL instead of auto_increment.
ALTER TABLE your_table_name ADD COLUMN id SERIAL NOT NULL PRIMARY KEY
ALTER TABLE `table` ADD `id` INT NOT NULL AUTO_INCREMENT unique
Try this. No need to drop your primary key.
This SQL request works for me :
ALTER TABLE users
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ;
If you want to add an id with a primary key and identity:
ALTER TABLE user ADD id INT NOT NULL AUTO_INCREMENT FIRST , ADD PRIMARY KEY (id);
Check for already existing primary key with different column. If yes, drop the primary key using:
ALTER TABLE Table1
DROP CONSTRAINT PK_Table1_Col1
GO
and then write your query as it is.
Proceed like that :
Make a dump of your database first
Remove the primary key like that
ALTER TABLE yourtable DROP PRIMARY KEY
Add the new column like that
ALTER TABLE yourtable add column Id INT NOT NULL AUTO_INCREMENT FIRST, ADD primary KEY Id(Id)
The table will be looked and the AutoInc updated.

Add Auto-Increment ID to existing table?

I have a pre-existing table, containing 'fname', 'lname', 'email', 'password' and 'ip'. But now I want an auto-increment column. However, when I enter:
ALTER TABLE users
ADD id int NOT NULL AUTO_INCREMENT
I get the following:
#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key
Any advice?:)
Try this
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT;
for an existing primary key
If you don't care whether the auto-id is used as PRIMARY KEY, you can just do
ALTER TABLE `myTable` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST;
I just did this and it worked a treat.
If you want to add AUTO_INCREMENT in an existing table, need to run following SQL command:
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key
First you have to remove the primary key of the table
ALTER TABLE nametable DROP PRIMARY KEY
and now yo can add the autoincrement ...
ALTER TABLE nametable ADD id INT NOT NULL AUTO_INCREMENT PRIMARY KEY
Well, you must first drop the auto_increment and primary key you have and then add yours, as follows:
-- drop auto_increment capability
alter table `users` modify column id INT NOT NULL;
-- in one line, drop primary key and rebuild one
alter table `users` drop primary key, add primary key(id);
-- re add the auto_increment capability, last value is remembered
alter table `users` modify column id INT NOT NULL AUTO_INCREMENT;
If you run the following command :
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This will show you the error :
ERROR 1060 (42S21): Duplicate column name 'id'
This is because this command will try to add the new column named id to the existing table.
To modify the existing column you have to use the following command :
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT PRIMARY KEY;
This should work for changing the existing column constraint....!
Delete the primary key of a table if it exists:
ALTER TABLE `tableName` DROP PRIMARY KEY;
Adding an auto-increment column to a table :
ALTER TABLE `tableName` ADD `Column_name` INT PRIMARY KEY AUTO_INCREMENT;
Modify the column which we want to consider as the primary key:
alter table `tableName` modify column `Column_name` INT NOT NULL AUTO_INCREMENT PRIMARY KEY;
Just change the ADD to MODIFY and it will works !
Replace
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT
To
ALTER TABLE users MODIFY id int NOT NULL AUTO_INCREMENT;
Drop the primary index from the table:
ALTER TABLE `tableName` DROP INDEX `PRIMARY`;
Then add the id column (without a primary index). I have used a big int because I am going to have lots of data but INT(11) should work just as well:
ALTER TABLE `tableName` ADD COLUMN `id` BIGINT(11) NOT NULL FIRST;
Then modify the column with auto-increment (thanks php). It needs to be a primary key:
ALTER TABLE `tableName ` MODIFY COLUMN `id` BIGINT(11) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
I have just tried this on a table of mine and it appears to have worked.
ALTER TABLE users CHANGE id int( 30 ) NOT NULL AUTO_INCREMENT
the integer parameter is based on my default sql setting
have a nice day
ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT primary key FIRST
For PostgreSQL you have to use SERIAL instead of auto_increment.
ALTER TABLE your_table_name ADD COLUMN id SERIAL NOT NULL PRIMARY KEY
ALTER TABLE `table` ADD `id` INT NOT NULL AUTO_INCREMENT unique
Try this. No need to drop your primary key.
This SQL request works for me :
ALTER TABLE users
CHANGE COLUMN `id` `id` INT(11) NOT NULL AUTO_INCREMENT ;
If you want to add an id with a primary key and identity:
ALTER TABLE user ADD id INT NOT NULL AUTO_INCREMENT FIRST , ADD PRIMARY KEY (id);
Check for already existing primary key with different column. If yes, drop the primary key using:
ALTER TABLE Table1
DROP CONSTRAINT PK_Table1_Col1
GO
and then write your query as it is.
Proceed like that :
Make a dump of your database first
Remove the primary key like that
ALTER TABLE yourtable DROP PRIMARY KEY
Add the new column like that
ALTER TABLE yourtable add column Id INT NOT NULL AUTO_INCREMENT FIRST, ADD primary KEY Id(Id)
The table will be looked and the AutoInc updated.

How to add a primary key to a MySQL table?

This is what I tried but it fails:
alter table goods add column `id` int(10) unsigned primary AUTO_INCREMENT;
Does anyone have a tip?
After adding the column, you can always add the primary key:
ALTER TABLE goods ADD PRIMARY KEY(id)
As to why your script wasn't working, you need to specify PRIMARY KEY, not just the word PRIMARY:
alter table goods add column `id` int(10) unsigned primary KEY AUTO_INCREMENT;
Existing Column
If you want to add a primary key constraint to an existing column all of the previously listed syntax will fail.
To add a primary key constraint to an existing column use the form:
ALTER TABLE `goods`
MODIFY COLUMN `id` INT(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
If your table is quite big better not use the statement:
alter table goods add column `id` int(10) unsigned primary KEY AUTO_INCREMENT;
because it makes a copy of all data in a temporary table, alter table and then copies it back.
Better do it manually.
Rename your table:
rename table goods to goods_old;
create new table with primary key and all necessary indexes:
create table goods (
id int(10) unsigned not null AUTO_INCREMENT
... other columns ...
primary key (id)
);
move all data from the old table into new, disabling keys and indexes to speed up copying:
-- USE THIS FOR MyISAM TABLES:
SET UNIQUE_CHECKS=0;
ALTER TABLE goods DISABLE KEYS;
INSERT INTO goods (... your column names ...) SELECT ... your column names FROM goods_old;
ALTER TABLE goods ENABLE KEYS;
SET UNIQUE_CHECKS=1;
OR
-- USE THIS FOR InnoDB TABLES:
SET AUTOCOMMIT = 0; SET UNIQUE_CHECKS=0; SET FOREIGN_KEY_CHECKS=0;
INSERT INTO goods (... your column names ...) SELECT ... your column names FROM goods_old;
SET FOREIGN_KEY_CHECKS=1; SET UNIQUE_CHECKS=1; COMMIT; SET AUTOCOMMIT = 1;
It takes 2 000 seconds to add PK to a table with ~200 mln rows.
Not sure if this matters to anyone else, but I prefer the id for the table to be the first column in the database. The syntax for that is:
ALTER TABLE your_db.your_table ADD COLUMN `id` int(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT FIRST;
Which is just a slight improvement over the first answer. If you wanted it to be in a different position, then
ALTER TABLE unique_address ADD COLUMN `id` int(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT AFTER some_other_column;
HTH,
-ft
Use this query,
alter table `table_name` add primary key(`column_name`);
This code work in my mysql db:
ALTER TABLE `goods`
ADD COLUMN `id` INT NOT NULL AUTO_INCREMENT,
ADD PRIMARY KEY (`id`);
For me, none of suggestions worked giving me the errors of syntax, so I just gave a try using phpmyadmin(version 4.9.2), (10.4.10-MariaDB) and added id column with auto-increment primary key. Id column was nicely added from the first element.
Query output was:
ALTER TABLE table_name ADD id INT NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (id);
ALTER TABLE GOODS MODIFY ID INT(10) NOT NULL PRIMARY KEY;
Try this,
alter table goods add column `id` int(10) unsigned primary key auto_increment
ALTER TABLE `goods`
MODIFY COLUMN `id` INT(10) UNSIGNED PRIMARY KEY AUTO_INCREMENT;
If previously you already have one or more primary keys and you want to include more column as primary key, you need to add DROP PRIMARY KEY in your statement and re-mention previous keys along with new ones in ADD PRIMARY KEY section. Take a look at the following example..
Previously, my_test_table had only a single primary key column named old_key. Then we add a new column named new_key.
ALTER TABLE my_test_table ADD COLUMN new_key INT; -- Or whatever data type you need
If we want to make our table to have primary key set {old_key, new_key}, then the following statement can be used:
ALTER TABLE my_test_table
DROP PRIMARY KEY, -- You have to add this
ADD PRIMARY KEY(
old_key, -- Re-mention the old key
new_key -- And mention also the new one
);
Remove quotes to work properly...
alter table goods add column id int(10) unsigned primary KEY AUTO_INCREMENT;

How to add AUTO_INCREMENT to an existing column?

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);