MYSQL variables in php query

Question

The solution to this problem might be a simple over sight of mine.

I am trying to run a MYSQL query stored as a string in PHP. The query runs fine using DBM tool like Navicat but returns false in my PHP development enviorment. Is there something I've over looked?

SET @running_sum = 0;

SELECT
    TID,
    SumTotal,
    T.`Freight`,
    T.`Insurance`,
    T.`Discount`,
    CONCAT(
        '$',
        FORMAT(
            @running_sum :=@running_sum + SumTotal + T.`Freight` + T.`Insurance` - T.`Discount`,
            2
        )
    ) AS 'Running Total'
FROM
    (
        SELECT
            TID,
            SUM(Quantity * UnitNetValue) AS SumTotal,
            T.`Freight`,
            T.`Insurance`,
            T.`Discount`
        FROM
            Transactions T
        JOIN `Transactions_Products` P ON T.TransactionID = P.TID
        WHERE
            (
                T.TemplateName = ''
                OR T.TemplateName IS NULL
            )
        AND T. STATUS = 1
        GROUP BY
            TransactionID

    ) AS T;

I am executing the query like this;

$result = mysql_query($this->query);

$this->query is a string which holds the above query, as it is displayed to you above.

Answer 1

There is also possible to use multi_query method instead of query of MySQLi:

$query = "SET @running_sum = 0; SELECT ...";
$db_link->multi_query($query);