Using MYSQL LAST_INSERT_ID() to retrive the ID of inserted row?

Question

I have a table which has got a column with AUTO INCREMENT. I have to retrieve the value of this column when inserting a new row (i need the value of the new row). I've read a lot about it and found different solutions, one is to use SELECT LAST_INSERT_ID(). I've heard many different things about this. Can I or can i not use this? I am worried that another connection may insert a new row before I am able to call SELECT LAST_INSERT_ID(), and therefore get the wrong ID.

To sum up, is it safe to use SELECT LAST_INSERT_ID()? If not, how can I retrieve the last inserted id in a safe way?

Answer 1

I dont think that you need to worry about the case you are mentioning here.

From Mysql documentation:
The ID that was generated is maintained in the server on a per-connection basis. This means that the value returned by the function to a given client is the first AUTO_INCREMENT value generated for most recent statement affecting an AUTO_INCREMENT column by that client. This value cannot be affected by other clients, even if they generate AUTO_INCREMENT values of their own. This behavior ensures that each client can retrieve its own ID without concern for the activity of other clients, and without the need for locks or transactions.

For detailed info, refer this

Although, i would love to read from others if they have different opinion.

Answer 2

If it is critical for you to have last id of the table, you can lock the table for writes, then make SELECT MAX(id) FROM table_name and then unlock table.

Answer 3

The ID generated is on a per-connection basis so you shouldn't have any problems! This post goes into more detail.

Answer 4

Yes, according to official documentation, it is safe:

The ID that was generated is maintained in the server on a per-connection basis. This means that the value returned by the function to a given client is the first AUTO_INCREMENT value generated for most recent statement affecting an AUTO_INCREMENT column by that client. This value cannot be affected by other clients, even if they generate AUTO_INCREMENT values of their own. This behavior ensures that each client can retrieve its own ID without concern for the activity of other clients, and without the need for locks or transactions.

Taken From: MYSQL Documentation 12.13. Information Functions

Answer 5

If you're using PDO, use PDO::lastInsertId.

and if you are using mysql, use mysqli::$insert_id.

and yes it is safe to use AI This is the post which says this : http://dev.mysql.com/doc/refman/5.0/en/getting-unique-id.html

and instead of using select statement directly, try to use preparedStatement.

Also you can use the Lock