Let's say I am doing a MySQL INSERT
into one of my tables and the table has the column item_id
which is set to autoincrement
and primary key
.
How do I get the query to output the value of the newly generated primary key item_id
in the same query?
Currently I am running a second query to retrieve the id but this hardly seems like good practice considering this might produce the wrong result...
If this is not possible then what is the best practice to ensure I retrieve the correct id?
INSERT
query like that; why do you think it might produce the wrong result?
You need to use the LAST_INSERT_ID()
function: http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_last-insert-id
Eg:
INSERT INTO table_name (col1, col2,...) VALUES ('val1', 'val2'...);
SELECT LAST_INSERT_ID();
This will get you back the PRIMARY KEY
value of the last row that you inserted:
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.
So the value returned by LAST_INSERT_ID()
is per user and is unaffected by other queries that might be running on the server from other users.
BEWARE !! of LAST_INSERT_ID()
if trying to return this primary key value within PHP.
I know this thread is not tagged PHP, but for anybody who came across this answer looking to return a MySQL insert id from a PHP scripted insert using standard mysql_query
calls - it wont work and is not obvious without capturing SQL errors.
The newer mysqli
supports multiple queries - which LAST_INSERT_ID()
actually is a second query from the original.
IMO a separate SELECT
to identify the last primary key is safer than the optional mysql_insert_id()
function returning the AUTO_INCREMENT ID
generated from the previous INSERT
operation.
LAST_INSERT_ID
is a per-connection MySQL function. If you query for the last insert ID it is possible a separate connection will have performed a write and you will have the wrong ID.
mysql_insert_id()
also works on a per connection basis, but it also suffers strange behaviour as seen here stackoverflow.com/a/897374/1305910 in the comment by Cliffordlife -- nevermind we should all have been using mysqli
From the LAST_INSERT_ID()
documentation:
The ID that was generated is maintained in the server on a per-connection basis
That is if you have two separate requests to the script simultaneously they won't affect each others' LAST_INSERT_ID()
(unless you're using a persistent connection perhaps).
Here what you are looking for !!!
select LAST_INSERT_ID()
This is the best alternative of SCOPE_IDENTITY()
function being used in SQL Server
.
You also need to keep in mind that this will only work if Last_INSERT_ID()
is fired following by your Insert
query. That is the query returns the id inserted in the schema. You can not get specific table's last inserted id.
For more details please go through the link The equivalent of SQLServer function SCOPE_IDENTITY() in mySQL?
You will receive these parameters on your query result:
"fieldCount": 0,
"affectedRows": 1,
"insertId": 66,
"serverStatus": 2,
"warningCount": 1,
"message": "",
"protocol41": true,
"changedRows": 0
The insertId
is exactly what you need.
(NodeJS-mySql)
If in python using pymysql
, from the cursor you can use cursor.lastrowid
.
It is a documented extension in PEP-249
DB API standard, and also works with other Python MySQL implementations.
You need to use the LAST_INSERT_ID() function with transaction:
START TRANSACTION;
INSERT INTO dog (name, created_by, updated_by) VALUES ('name', 'migration', 'migration');
SELECT LAST_INSERT_ID();
COMMIT;
http://dev.mysql.com/doc/refman/5.0/en/information-functions.html#function_last-insert-id
This function will be return last inserted primary key in table.
If you need the value before insert a row:
CREATE FUNCTION `getAutoincrementalNextVal`(`TableName` VARCHAR(50))
RETURNS BIGINT
LANGUAGE SQL
NOT DETERMINISTIC
CONTAINS SQL
SQL SECURITY DEFINER
COMMENT ''
BEGIN
DECLARE Value BIGINT;
SELECT
AUTO_INCREMENT INTO Value
FROM
information_schema.tables
WHERE
table_name = TableName AND
table_schema = DATABASE();
RETURN Value;
END
You can use this in a insert:
INSERT INTO
document (Code, Title, Body)
VALUES (
sha1( concat (convert ( now() , char), ' ', getAutoincrementalNextval ('document') ) ),
'Title',
'Body'
);
Simply use:
$last_id = mysqli_insert_id($conn);
If you are using PHP: On a PDO object you can simple invoke the lastInsertId method after your insert.
Otherwise with a LAST_INSERT_ID you can get the value like this: SELECT LAST_INSERT_ID();
i used return $this->db->insert_id();
for Codeigniter
Do this:
$idc = DB::table('tb_clients')->insertGetId([
'ide' => $ide,
'nome' => $nome,
'email' => $email
]);
on $idc you will get the last id
I just want to share my approach to this in PHP, some of you may found it not an efficient way but this is a 100 better than other available options.
generate a random key and insert it into the table creating a new row. then you can use that key to retrieve the primary key. use the update to add data and do other stuff.
doing this way helps to secure a row and have the correct primary key.
I really don't recommend this unless you don't have any other options.
Success story sharing
PRIMARY KEY
value of the last row that you inserted, because it's per connection - each connection to the server will maintain it's own value for this. I've updated the answer to clarify this.