php pdo_dblib with sql server

Question

I use PHP extension pdo_dblib to access MS SQL SERVER. I used this connection:

$pdosql = new PDO ("dblib:host=$hostname:$port;dbname=$dbname","$username","$pw");   

I retrive the data from table:

$sql = 'SELECT cust_id FROM customers ORDER BY cust_id';
$rez = $pdosql->query($sql);
while($arr = $rez->fetch(PDO::FETCH_NUM)){
    $sql1 = 'SELECT employee_name FROM employes ORDER BY emplyee_name';
    $rez1 = $pdosql->prepare($sql1);
    $rez1->bindValue(':id_cust',$arr[0],PDO::PARAM_INT);
    $rez1->execute();
    $arr1 = $rez1->fetch(PDO::FETCH_NUM);
    echo $arr1[0];
}

Instead to show first employee's name for all 20 customers, query return data only for first customer. I found a solution to open a new PDO before while :

$pdosql = new PDO ("dblib:host=$hostname:$port;dbname=$dbname","$username","$pw");

And all works fine. Is there another solution?

Because if I have while in while , the time to retrieve data is increasing.

If I used this code in mySQL database (with proper connection), all works fine.

Answer 1

It looks like the query inside the loop doesn't include the parameter. Perhaps add "WHERE cust_id = :id_cust" to the query:

$sql1 = 'SELECT employee_name FROM employes WHERE cust_id = :id_cust ORDER BY emplyee_name';

Also, you may be able to optimize your code a bit by making one query the to database using a join. Something like this:

SELECT 
    B.employee_name
FROM customers A 
INNER JOIN employees B 
ON      A.cust_id = B.cust_id
ORDER BY 
    A.cust_id

However, I'm also unsure of your database design and not sure how customers and employees are actually related.

Answer 2

我同意，在查询中使用内部联接，在表之间使用一个公共字段，这将更实用，这将向您显示所需的结果，我建议根据经验或您想使用存储过程。