How to call a stored procedure within another stor

Question

I am struggling to call a stored procedure within another stored procedure. Like it is now the stored procedure never return the SELECT statement back as a result to the mysqli call in PHP (but it works fine in MySQL workbench).

DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `new_bid`(IN bid_in decimal(6,2),
                                                      IN ticker_in varchar(5),
                                                      IN share_amount_in BIGINT)
BEGIN

    DECLARE company_id_var INT;
    DECLARE highest_bid BIT;
    DECLARE generated_bid_id BIGINT;

    SET company_id_var = (SELECT ID
                      FROM Companies
                      WHERE Ticker = ticker_in);

    -- Put the bid into the Bids table.
    INSERT INTO Bids(company_id,bid,share_amount)
    VALUES (company_id_var,bid_in,share_amount_in);

    SET generated_bid_id = LAST_INSERT_ID();

    CALL check_available_shares(bid_in,share_amount_in,generated_bid_id,@shares_left);

    -- Check if the bid is higher than the current highest bid.
    -- If so update the CurrentState table to have the new value.
    UPDATE CurrentState SET buyer = bid_in
                        WHERE ID = company_id_var
                        AND buyer < bid_in;

    IF (ROW_COUNT() = 1)
     THEN
     SELECT 1 AS highest_bid, @shares_left AS shares_left, CS.buyer, CS.seller, CS.last_price, CO.name,  CO.ticker
     FROM CurrentState CS, Companies CO
     WHERE CS.id = CO.id
     AND CO.ticker = ticker_in;
    ELSE
     SELECT 0 AS highest_bid, @shares_left AS shares_left, CS.buyer, CS.seller, CS.last_price, CO.name,  CO.ticker
     FROM CurrentState CS, Companies CO
     WHERE CS.id = CO.id
     AND CO.ticker = ticker_in;
    END IF;
END

If I remove the "CALL" function from this stored procedure it returns one of the SELECT statement at the bottom, but if I keep the "CALL" function it does not return anything. I have tried with exec and execute but that only gives me syntax error when I try to save the procedure within MySQL workbench. This problem is related to https://stackoverflow.com/questions/23193085/mysqli-does-not-return-any-results-but-stored-procedure-does. But it seems that that problem may be related to how mysqli handles the execution of the stored procedure since it works fine when I call the stored procedure manually in mySQL workbench(?)

Answer 1

After hours of banging my head against a wall I found a solution. Since this stored procedure calls another stored procedure which uses a cursor I had to use the $mysqli->multi_query() function. Here's how I got it working:

new_bid stored procedure:

-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `new_bid`(IN bid_in decimal(6,2),
                                                      IN ticker_in varchar(5),
                                                      IN share_amount_in BIGINT)
BEGIN

    -- Store the company ID into a variable as this value will used more than once.
    DECLARE company_id_var INT;
    DECLARE ParamtoPass INT;
    DECLARE highest_bid BIT;
    DECLARE generated_bid_id BIGINT;

    SET company_id_var = (SELECT ID
                      FROM Companies
                      WHERE Ticker = ticker_in);

    -- Put the bid into the Bids table.
    INSERT INTO Bids(company_id,bid,share_amount)
    VALUES (company_id_var,bid_in,share_amount_in);

    SET generated_bid_id = LAST_INSERT_ID();
    -- EXECUTE check_available_shares bid_in, @share_amount_in,@generated_bid_id,@shares_left;
    CALL check_available_shares (bid_in,@share_amount_in,generated_bid_id,@shares_left);

    -- Check if the bid is higher than the current highest bid.
    -- If so update the CurrentState table to have the new value.
    UPDATE CurrentState SET buyer = bid_in
                        WHERE ID = company_id_var
                        AND buyer < bid_in;

    IF (ROW_COUNT() = 1)
     THEN
     SELECT 1 AS highest_bid, @shares_left AS shares_left, CS.buyer, CS.seller, CS.last_price, CO.name,  CO.ticker
     FROM CurrentState CS, Companies CO
     WHERE CS.id = CO.id
     AND CO.ticker = ticker_in;
    ELSE
     SELECT 0 AS highest_bid, @shares_left AS shares_left, CS.buyer, CS.seller, CS.last_price, CO.name,  CO.ticker
     FROM CurrentState CS, Companies CO
     WHERE CS.id = CO.id
     AND CO.ticker = ticker_in;
    END IF;
END

check_available_shares procedure:

-- --------------------------------------------------------------------------------
-- Routine DDL
-- Note: comments before and after the routine body will not be stored by the server
-- --------------------------------------------------------------------------------
DELIMITER $$

CREATE DEFINER=`root`@`localhost` PROCEDURE `check_available_shares`(IN bid_in decimal(6,2),
                                                                     IN share_amount_in int,
                                                                     IN bid_id bigint,
                                                                     OUT shares_left BIT)
BEGIN
    DECLARE num_shares INT;
    DECLARE selling_id INT;
    DECLARE selling_price DECIMAL(6,2);
    DECLARE done INT DEFAULT FALSE;

    DECLARE cur CURSOR FOR SELECT share_amount,sell_price,ID
                           FROM ShareSell
                           WHERE sell_price <= bid_in
                           ORDER BY sell_price ASC, sell_timestamp ASC;

    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE;

    OPEN cur;   /* open cursor */

    read_loop: LOOP
        FETCH NEXT FROM cur
                   INTO num_shares, selling_price, selling_id;

        IF (done) THEN
            LEAVE read_loop;
        END IF;

        IF ((share_amount_in - num_shares) > 0) THEN
            SET share_amount_in = (share_amount_in - num_shares);

            DELETE FROM ShareSell
                   WHERE ID = selling_id;
        ELSEIF((share_amount_in - num_shares) < 0) THEN
            UPDATE ShareSell
            SET share_amount = (share_amount - share_amount_in)
            WHERE ID = selling_id;

            DELETE FROM Bids
            WHERE ID = bid_id;

            LEAVE read_loop;
        ELSE
            DELETE FROM ShareSell
                   WHERE ID = selling_id;

            DELETE FROM Bids
                   WHERE ID = bid_id;
        END IF;

        SELECT num_shares,selling_price;
    END LOOP;

    CLOSE cur;

    IF (share_amount_in > 0) THEN
        UPDATE Bids
        SET share_amount = share_amount_in
        WHERE ID = bid_id;
        SET shares_left = 1;
    ELSE
        SET shares_left = 0;
    END IF;
END

And finally the PHP call:

$bid = 43.10;
$ticker = "GOS";
$share_amount = 1000;

if ($mysqli->multi_query("CALL new_bid($bid,'$ticker',$share_amount)"))
{
 if ($result = $mysqli->store_result())
 {
   while ($row = $result->fetch_assoc())
   {
     print_r($row);
   }

   $result->close();
 }
}

Answer 2

Thanks! This was exactly my problem too. I too broke my head on an exact similar problem (see PHP mysqli is NOT trapping some errors when calling stored procedure). Your post helped me solve my problem!

I too had a case of PHP calling SP1, which in turn called SP2, and everything working fine in a mysql client but breaking when called by PHP! And indeed, I too had had a SELECT of a result set in SP2. And my problem symptoms were exactly identical to yours, and it never struck me to use multi_query().

I notice that you also SELECT a "result set* in check_available_shares (see line SELECT num_shares,selling_price;). Not sure why you have this line. If you remove that line, I suspect you should be able to do a query() instead of multi_query().