Get current auto_increment value

Question

I am doing mysql insert for my table using php. Autoincrement column name is "link_id" and "alias" colum is used to make SEO friendly url.

During my insert, I would like to attach link_id value at the end of my alias column.

So I need to know what is the being inserted link_id value.

I do not want to do another query.

mysql_insert_id() does not work, since its using previous query, and not current query.

Thanks

Answer 1

You should use SHOW TABLE STATUS :

$query = mysql_query("SHOW TABLE STATUS LIKE tablename");
$row = mysql_fetch_array($query);
$next_id = $row["Auto_increment"];

It will give you the current status of auto_increment column.

EDITED:

In one query you can do it like this:

INSERT INTO table_schema.table_name(column_name) 
VALUES (("SELECT AUTO_INCREMENT 
         FROM INFORMATION_SCHEMA.TABLES 
         WHERE TABLE_SCHEMA = 'table_schema' 
            AND TABLE_NAME = 'table_name'"))

It will give you the new auto_increment value in the column column_name .

Answer 2

Have you considered a trigger in MySQL ? Something like:

DELIMITER //
CREATE TRIGGER `add_alias_id` AFTER INSERT ON `someTable`
    FOR EACH ROW BEGIN
        UPDATE 
            `someTable` 
        SET 
            `alias` = CONCAT(`alias`,NEW.`link_id`)
        WHERE
            `link_id` = NEW.`link_id`;
    END;    
//
DELIMITER ;

EDIT: I was recently working for a company whose flagship software used to assume that max(id) + 1 = next id. The problem is concurrency; it's rare, but two people can get the same id, causing all sorts of chaos. Be extremely careful trying to predict the value.

Answer 3

I handle this type of scenario on the SELECT end.

For Example: insert into tablename(aliasroot) values('index.php?link_id=');

This would give you for example

In my select I would do 'select concat(aliasroot,link_id) as alias from tablename'

Answer 4

you could use mysql_insert_id() ++, though that won't always be reliable.

what would be better would be to insert the query, then append the current id using CONCAT()