PHP get return value of stored procedure

问题

I have pleasure to work with legacy PHP application using SQL Server via PDO.

How in PHP can I retrieve return value of stored procedure which is using RETURN statement as output channel?

Example procedure

CREATE PROCEDURE [dbo].[mleko_test]
    @param INT
AS
  BEGIN
    RETURN @param * 3;
  END
GO

If possible, I would prefer to not modify procedure.

I am aware that there are similar questions, but they don't cover this case

Get RETURN value from stored procedure in SQL
Get Return Value from SQL Stored Procedure using PHP

回答1:

Execute stored procedure like this: "exec ?=mleko_test(?)".

Working example:

<?php
#------------------------------
# Connection info
#------------------------------
$server = 'server\instance,port';
$database = 'database';
$uid = 'user';
$pwd = 'password';

#------------------------------
# With PDO
#------------------------------
try {
    $conn = new PDO("sqlsrv:server=$server;Database=$database", $uid, $pwd);
    $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
} catch( PDOException $e ) {
    die( "Error connecting to SQL Server" );
}

try {
    $sql = "exec ?=mleko_test(?)";
    $param = 3;
    $spresult = 0;
    $stmt = $conn->prepare($sql);
    $stmt->bindParam(1, $spresult, PDO::PARAM_INT|PDO::PARAM_INPUT_OUTPUT, PDO::SQLSRV_PARAM_OUT_DEFAULT_SIZE);
    $stmt->bindParam(2, $param);
    $stmt->execute();
} catch( PDOException $e ) {
    die( "Error connecting to SQL Server" );
}

$stmt = null;
$conn = null;

echo 'Stored procedure return value (with PDO): '.$spresult."</br>";

#------------------------------
# Without PDO
#------------------------------
$cinfo = array(
    "Database" => $database,
    "UID" => $uid,
    "PWD" => $pwd
);

$conn = sqlsrv_connect($server, $cinfo);
if( $conn === false )
{
    echo "Error (sqlsrv_connect): ".print_r(sqlsrv_errors(), true);
    exit;
}

$sql = "exec ?=mleko_test(?)";
$param = 3;
$spresult = 0;
$params = array(   
    array(&$spresult, SQLSRV_PARAM_OUT), 
    array($param, SQLSRV_PARAM_IN),  
); 
$stmt = sqlsrv_query($conn, $sql, $params);
if( $stmt === false ) {
    echo "Error (sqlsrv_query): ".print_r(sqlsrv_errors(), true);
    exit;
}

while ($row = sqlsrv_fetch_array($stmt, SQLSRV_FETCH_ASSOC)) {
}

sqlsrv_free_stmt($stmt);
sqlsrv_close($conn);

echo 'Stored procedure return value (without PDO): '.$spresult."</br>";
?>

Notes:

Tested with PHP 7.1.12 and PHP Driver for SQL Server (pdo_sqlsrv version 4.3.0+9904).

回答2:

I came to a solution using multi-query but @Zhorov answer is cleaner

<?php
$connection = new PDO($connectionString, $DB_USERNAME, $DB_PASSWORD);

$stmt = $connection->prepare(<<<SQL
DECLARE @a INT;
EXEC @a = mleko_test :in
SELECT @a AS result;
SQL
);

$stmt->execute([":in" => 123]);
echo $stmt->fetch()["result"] . "\n";