MySQL retrieve variable from Stored Procedure in PHP PDO
I've seen this question asked a load of times, but they're all really long, and I just can't get my head around what they're doing ... So, could someone tell me how to get the LAST_INSERT_ID()
from this procedure into php using PDO:
Table:
CREATE TABLE names (
ID INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
name varchar(50) NOT NULL
)
Procedure:
CREATE DEFINER=`root`@`localhost` PROCEDURE `simpleProcedure`(newname varchar(50), OUT returnid INT(11))
BEGIN
INSERT INTO names (name) VALUES (newname);
SET returnid = LAST_INSERT_ID();
END
PHP code I've tried:
$stmt=$db->prepare("CALL simpleProcedure(:name,:returnid)");
$stmt->bindValue(':name',$name,PDO::PARAM_STR);
$stmt->bindParam(':returnid',$returnid,PDO::PARAM_INT,11);
$stmt->execute();
echo $returnid;
But, probably obvious to someone who has more brain cells than me, this doesn't work. Any help appreciated.
Reference as to why I believe this SHOULD work:
http://www.php.net/pdo.prepared-statements (Example #4)
Solution 1:
It turns out that this is a bug that has been going on for a long time... since 2005!
Here is the original bug report: 2005 through to 2013. And here is the new bug report: From 2013 to the present.
There are various approaches to getting the answer returned, I found one of them and demonstrate it...
The 'trick' is that to get the output from a 'mysql' procedure. It is a 'two stage' process.
The first part is to run the procedure with your inputs, and also tell it what MYSQL variables to store the result in.
Then, you run a separate query to 'select' those 'mysql' variables.
It is described quite clearly here: php-calling-mysql-stored-procedures
Update (Jan 2017):
Here is an example showing the use of variables for 'IN', 'INOUT' and 'OUT' Mysql procedure parameters.
Before we start here are some tips:
- When developing: Run PDO in 'emulates mode' as it is more reliable at determining errors in the procedure call.
- Only bind PHP variables to the procedure 'IN' parameters.
You will get some really odd runtime errors when you try binding variables to INOUT and OUT parameters.
As usual I tend to provide rather more comments than are required ;-/
Runtime Environment (XAMPP):
- PHP: 5.4.4
- Mysql: 5.5.16
Source Code:
- SQL Procedure
- PHP with output
SQL Code:
CREATE PROCEDURE `demoSpInOutSqlVars`(IN pInput_Param INT, /* PHP Variable will bind to this*/
/* --- */
INOUT pInOut_Param INT, /* contains name of the SQL User variable that will be read and set by mysql */
OUT pOut_Param INT) /* contains name of the SQL User variable that will be set by mysql */
BEGIN
/*
* Pass the full names of SQL User Variable for these parameters. e.g. '@varInOutParam'
* These 'SQL user variables names' are the variables that Mysql will use for:
* 1) finding values
* 2) storing results
*
* It is similar to 'variable variables' in PHP.
*/
SET pInOut_Param := ABS(pInput_Param) + ABS(pInOut_Param); /* always positive sum */
SET pOut_Param := ABS(pInput_Param) * -3; /* always negative * 3 */
END$$
PHP Code:
DB Connection:
$db = appDIC('getDbConnection', 'default'); // get the default db connection
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, true);
$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
Note: The output is the same with EMULATE_PREPARES
= false.
Set all PHP Variables that will be used:
$phpInParam = 5;
$phpInOutParam = 404; /* PHP InOut variable ==> read and should be changed */
$phpOutParam = null; /* PHP Out variable ==> should be changed */
Define and Prepare the SQL procedure call:
$sql = "call demoSpInOut(:phpInParam,
@varInOutParam, /* mysql variable name will be read and updated */
@varOutParam)"; /* mysql variable name that will be written to */
$stmt = $db->prepare($sql);
Bind PHP Variables and Set SQL Variables:
-
1) bind the PHP variables
$stmt->bindParam(':phpInParam', $phpInParam, PDO::PARAM_INT);
-
2) Set the SQL User INOUT variables
$db->exec("SET @varInOutParam = $phpInOutParam"); // This is safe as it just sets the value into the MySql variable.
Execute the procedure:
$allOk = $stmt->execute();
Get the SQL Variables into the PHP variables:
$sql = "SELECT @varInOutParam AS phpInOutParam,
@varOutParam AS phpOutParam
FROM dual";
$results = current($db->query($sql)->fetchAll());
$phpInOutParam = $results['phpInOutParam'];
$phpOutParam = $results['phpOutParam'];
Note: maybe not the best way ;-/
Display the PHP variables
"$phpInParam:" => "5"
"$phpInOutParam:" => "409"
"$phpOutParam:" => "-15"