homerun
homerun

Reputation: 20775

How to reset AUTO_INCREMENT in MySQL

How can I reset the AUTO_INCREMENT of a field?

I want it to start counting from 1 again.

Upvotes: 1664

Views: 1975176

Answers (28)

ALTER TABLE `table_name` AUTO_INCREMENT = 1

You can also set it to the max value available. Example:

SET @max_value = (SELECT MAX(your_id) FROM table_name);

Reset AUTO_INCREMENT to the maximum existing value plus one

ALTER TABLE users AUTO_INCREMENT = @max_value + 1;

Upvotes: 0

cronoklee
cronoklee

Reputation: 6722

None of the answers worked for me. I had duplicated & emptied my innoDB table and wanted to reset the counter back to 1. The only way I could find to solve it was:

  1. Convert the table to MyIsam
  2. Change the auto-increment to 1 as suggested in other answers
  3. Add a new empty row to the table (presumably this resets the internal max id counter)
  4. Change the table back to InnoDB
  5. Delete the empty row

Upvotes: 0

Pavel Železný
Pavel Železný

Reputation: 310

If you are looking for a solution that fixes all of the auto_increment column values in all tables in the schema, the following code can help you:

delimiter $$
create procedure fix_autoincrement(tableschema varchar(200))
begin
    declare id_column varchar(200);

    for tables in (
        select
            table_name 
        from information_schema.tables 
        where table_schema = tableschema
        and `auto_increment` is not null
    )
    do
        select
            `column_name` into id_column
        from information_schema.columns 
        where table_schema = tableschema
        and table_name = tables.table_name 
        and extra = 'auto_increment';
    
        set @get_next_inc = concat('select @next_inc := coalesce(max(', id_column, '), 0) + 1 from ',tableschema,'.',tables.table_name,';');
        prepare stmt from @get_next_inc;
        execute stmt;
        select @next_inc as result;
        deallocate prepare stmt;
        
        set @alter_statement = concat('alter table ', tableschema,'.',tables.table_name, ' auto_increment = ', @next_inc, ';');
        prepare stmt from @alter_statement;
        execute stmt;
        deallocate prepare stmt;
    end for;
end $$
delimiter ;
call fix_autoincrement('table_schema_name');

Upvotes: 0

Niels
Niels

Reputation: 49919

You can reset the counter with:

ALTER TABLE tablename AUTO_INCREMENT = 1

InnoDB

For InnoDB you cannot set the auto_increment value lower or equal to the highest current index. (quote from ViralPatel):

Note that you cannot reset the counter to a value less than or equal to any that have already been used. For MyISAM, if the value is less than or equal to the maximum value currently in the AUTO_INCREMENT column, the value is reset to the current maximum plus one. For InnoDB, if the value is less than the current maximum value in the column, no error occurs and the current sequence value is not changed.

Aria

In a table with the Aria storage engine the auto_increment value can be set to any value, even lower than that of the current maximum. The next insert however will use the next available value (max + 1) ignoring the set value. If set to a higher value it will continue to use and increment from that. The documentation is not particular clear on that but this was observed with Mariadb 10.11.3

See also

See How can I reset an MySQL AutoIncrement using a MAX value from another table? on how to dynamically get an acceptable value.

Upvotes: 2638

AbdulBasit
AbdulBasit

Reputation: 1409

delete from url_rewrite where 1=1;
ALTER TABLE url_rewrite AUTO_INCREMENT = 1;

and then reindex

Upvotes: 1

Manohar Kumar
Manohar Kumar

Reputation: 613

Beware! TRUNCATE TABLE your_table will delete everything in your your_table.

You can also use the syntax TRUNCATE table like this:

TRUNCATE TABLE table_name

Upvotes: 28

bdalina
bdalina

Reputation: 523

Warning: If your column has constraints or is connected as a foreign key to other tables this will have bad effects.

First, drop the column:

ALTER TABLE tbl_name DROP COLUMN column_id

Next, recreate the column and set it as FIRST (if you want it as the first column I assume):

ALTER TABLE tbl_access ADD COLUMN `access_id` int(10) NOT NULL PRIMARY KEY AUTO_INCREMENT FIRST

Upvotes: 10

narasimharaosp
narasimharaosp

Reputation: 533

To update to the latest plus one id:

 ALTER TABLE table_name AUTO_INCREMENT = 
 (SELECT (id+1) id FROM table_name order by id desc limit 1);

Edit:

SET @latestId = SELECT MAX(id) FROM table_name;
SET @nextId = @latestId + 1;
ALTER TABLE table_name AUTO_INCREMENT = @nextId;

Not tested please test before you run*

Upvotes: 10

santosh mahule
santosh mahule

Reputation: 81

ALTER TABLE tablename AUTO_INCREMENT = 1

Upvotes: 8

Nghiệp
Nghiệp

Reputation: 4728

SET  @num := 0;

UPDATE your_table SET id = @num := (@num+1);

ALTER TABLE your_table AUTO_INCREMENT =1;

Upvotes: 186

If you're using PHPStorm's database tool you have to enter this in the database console:

ALTER TABLE <table_name> AUTO_INCREMENT = 0;

Upvotes: 2

Kim Stacks
Kim Stacks

Reputation: 10832

I googled and found this question, but the answer I am really looking for fulfils two criteria:

  1. using purely MySQL queries
  2. reset an existing table auto-increment to max(id) + 1

Since I couldn't find exactly what I want here, I have cobbled the answer from various answers and sharing it here.

Few things to note:

  1. the table in question is InnoDB
  2. the table uses the field id with type as int as primary key
  3. the only way to do this purely in MySQL is to use stored procedure
  4. my images below are using SequelPro as the GUI. You should be able to adapt it based on your preferred MySQL editor
  5. I have tested this on MySQL Ver 14.14 Distrib 5.5.61, for debian-linux-gnu

Step 1: Create Stored Procedure

create a stored procedure like this:

DELIMITER //
CREATE PROCEDURE reset_autoincrement(IN tablename varchar(200))
BEGIN

      SET @get_next_inc = CONCAT('SELECT @next_inc := max(id) + 1 FROM ',tablename,';');
      PREPARE stmt FROM @get_next_inc;
      EXECUTE stmt;
      SELECT @next_inc AS result;
      DEALLOCATE PREPARE stmt;

      set @alter_statement = concat('ALTER TABLE ', tablename, ' AUTO_INCREMENT = ', @next_inc, ';');
      PREPARE stmt FROM @alter_statement;
      EXECUTE stmt;
      DEALLOCATE PREPARE stmt;
END //
DELIMITER ;

Then run it.

Before run, it looks like this when you look under Stored Procedures in your database.

enter image description here

When I run, I simply select the stored procedure and press Run Selection

enter image description here

Note: the delimiters part are crucial. Hence if you copy and paste from the top selected answers in this question, they tend not to work for this reason.

After I run, I should see the stored procedure

enter image description here

If you need to change the stored procedure, you need to delete the stored procedure, then select to run again.

Step 2: Call the stored procedure

This time you can simply use normal MySQL queries.

call reset_autoincrement('products');

Originally from my own SQL queries notes in https://simkimsia.com/reset-mysql-autoincrement-to-max-id-plus-1/ and adapted for Stack Overflow.

Upvotes: 1

Peter Gruppelaar
Peter Gruppelaar

Reputation: 136

You need to follow the advice from Miles M's comment and here is some PHP code that fixes the range in MySQL. Also you need to open up the my.ini file (MySQL) and change max_execution_time=60 to max_execution_time=6000; for large databases.

Don’t use "ALTER TABLE tablename AUTO_INCREMENT = 1". It will delete everything in your database.

$con = mysqli_connect($dbhost, $dbuser, $dbpass, $database);
$res = mysqli_query($con, "select * FROM data WHERE id LIKE id ORDER BY id ASC");

$count = 0;
while ($row = mysqli_fetch_array($res)){
    $count++;

    mysqli_query($con, "UPDATE data SET id='".$count."' WHERE id='".$row['id']."'");
}
echo 'Done reseting id';
mysqli_close($con);

Upvotes: -5

Shabeer K
Shabeer K

Reputation: 1627

Try to run this query:

 ALTER TABLE tablename AUTO_INCREMENT = value;

Or try this query for the reset auto increment

 ALTER TABLE `tablename` CHANGE `id` `id` INT(10) UNSIGNED NOT NULL;

And set auto increment and then run this query:

  ALTER TABLE `tablename` CHANGE `id` `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT;

Upvotes: 4

Kristijan Iliev
Kristijan Iliev

Reputation: 4987

The auto-increment counter for a table can be (re)set in two ways:

  1. By executing a query, like others already explained:

    ALTER TABLE <table_name> AUTO_INCREMENT=<table_id>;

  2. Using Workbench or another visual database design tool. I am going to show in Workbench how it is done - but it shouldn't be much different in other tools as well. By right clicking over the desired table and choosing Alter table from the context menu. On the bottom you can see all the available options for altering a table. Choose Options and you will get this form:

    Enter image description here

Then just set the desired value in the field Auto increment as shown in the image. This will basically execute the query shown in the first option.

Upvotes: 3

Grumpy
Grumpy

Reputation: 2243

The best way is remove the field with AI and add it again with AI. It works for all tables.

Upvotes: -3

Abdul Aziz Al Basyir
Abdul Aziz Al Basyir

Reputation: 1245

It is for an empty table:

ALTER TABLE `table_name` AUTO_INCREMENT = 1;

If you have data, but you want to tidy up it, I recommend to use this:

ALTER TABLE `table_name` DROP `auto_colmn`;
ALTER TABLE `table_name` ADD  `auto_colmn` INT( {many you want} ) NOT NULL AUTO_INCREMENT FIRST ,ADD PRIMARY KEY (`auto_colmn`);

Upvotes: 14

SeanN
SeanN

Reputation: 663

As of MySQL 5.6 you can use the simple ALTER TABLE with InnoDB:

ALTER TABLE tablename AUTO_INCREMENT = 1;

The documentation are updated to reflect this:

13.1.7 ALTER TABLE Statement

My testing also shows that the table is not copied. The value is simply changed.

Upvotes: 28

salouri
salouri

Reputation: 821

The best solution that worked for me:

ALTER TABLE my_table MODIFY COLUMN ID INT(10) UNSIGNED;
COMMIT;
ALTER TABLE my_table MODIFY COLUMN ID INT(10) UNSIGNED AUTO_INCREMENT;
COMMIT;

It's fast, works with InnoDB, and I don't need to know the current maximum value!

This way. the auto increment counter will reset and it will start automatically from the maximum value exists.

Upvotes: 49

Miles M.
Miles M.

Reputation: 4169

Enter image description here

There is a very easy way with phpMyAdmin under the "operations" tab. In the table options you can set autoincrement to the number you want.

Upvotes: 63

Alin Razvan
Alin Razvan

Reputation: 1523

ALTER TABLE news_feed DROP id

ALTER TABLE news_feed ADD  id BIGINT( 200 ) NOT NULL AUTO_INCREMENT FIRST ,ADD PRIMARY KEY (id)

I used this in some of my scripts. The id field is dropped and then added back with previous settings. All the existent fields within the database table are filled in with the new auto increment values. This should also work with InnoDB.

Note that all the fields within the table will be recounted and will have other ids!!!.

Upvotes: 14

jeson
jeson

Reputation: 1

I suggest you to go to Query Browser and do the following:

  1. Go to schemata and find the table you want to alter.

  2. Right click and select copy create statement.

  3. Open a result tab and paste the create statement their.

  4. Go to the last line of the create statement and look for the Auto_Increment=N, (Where N is a current number for auto_increment field.)

  5. Replace N with 1.

  6. Press Ctrl + Enter.

Auto_increment should reset to one once you enter a new row in the table.

I don't know what will happen if you try to add a row where an auto_increment field value already exist.

Upvotes: -6

fyr
fyr

Reputation: 20869

Simply like this:

ALTER TABLE tablename AUTO_INCREMENT = value;

Reference: 13.1.9 ALTER TABLE Statement

Upvotes: 81

Mihai Galan
Mihai Galan

Reputation: 446

SET @num := 0;
UPDATE your_table SET id = @num := (@num+1);
ALTER TABLE your_table AUTO_INCREMENT =1;

Upvotes: 8

lreeder
lreeder

Reputation: 12224

The highest rated answers to this question all recommend "ALTER yourtable AUTO_INCREMENT= value". However, this only works when value in the alter is greater than the current max value of the autoincrement column. According to the MySQL 8 documentation:

You cannot reset the counter to a value less than or equal to the value that is currently in use. For both InnoDB and MyISAM, if the value is less than or equal to the maximum value currently in the AUTO_INCREMENT column, the value is reset to the current maximum AUTO_INCREMENT column value plus one.

In essence, you can only alter AUTO_INCREMENT to increase the value of the autoincrement column, not reset it to 1, as the OP asks in the second part of the question. For options that actually allow you set the AUTO_INCREMENT downward from its current max, take a look at Reorder / reset auto increment primary key.

Upvotes: 39

artsafin
artsafin

Reputation: 103

As of MySQL 5.6 the approach below works faster due to online DDL (note algorithm=inplace):

alter table tablename auto_increment=1, algorithm=inplace;

Upvotes: 8

BARIS KURT
BARIS KURT

Reputation: 537

ALTER TABLE `table_name`   DROP `id`;

ALTER TABLE `table_name` ADD `id` INT NOT NULL AUTO_INCREMENT FIRST, ADD PRIMARY KEY (`id`) ;

Shortly,First we deleted id column then added it with primary key id again...

Upvotes: 0

Cepheus
Cepheus

Reputation: 4913

I tried to alter the table and set auto_increment to 1 but it did not work. I resolved to delete the column name I was incrementing, then create a new column with your preferred name and set that new column to increment from the onset.

Upvotes: 1

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