Question

I’ve checked this in phpMyAdmin, and it returned 1 result:

    SELECT id, name
      FROM tbl_product_category
INNER JOIN tbl_product_cat_basket AS basket
        ON id = basket.cat_id
     WHERE basket.product_id = 2
     LIMIT 0,1

I then checked this in phpMyAdmin, and it returned COUNT = 1:

    SELECT COUNT(*)
      FROM tbl_product_category
INNER JOIN tbl_product_cat_basket AS basket
        ON id = basket.cat_id
     WHERE basket.product_id = 2
     LIMIT 0,1

Now I don’t understand why this causes $rows to return empty string or null:

function getProductCategory($product_id) {
    $sql = "SELECT id, name FROM tbl_product_category
        INNER JOIN tbl_product_cat_basket AS basket
                ON id = basket.cat_id
             WHERE basket.product_id = ?
             LIMIT 0,1;";
    $data = array((int)$product_id);
    $rows = dbRowsCount($sql, $data);
logErrors("getProductCategory(".$product_id.") returned rows: ".$rows);
    if ($rows == 1) {
        dbQuery($sql, $data);
        return dbFetch();
    } else {
        return null;
    }
}

The logErrors method gives me this output:

getProductCategory(1) returned rows:
getProductCategory(2) returned rows:
getProductCategory(3) returned rows:
getProductCategory(4) returned rows:
getProductCategory(5) returned rows:

and so I’m returning null from the method.

My dbRowsCount(...) method converts the SQL to do a SELECT COUNT(*), then dbQuery(...) executes the real query. This is strange because the dbRowsCount(...) so far has always returned the correct rows for my other queries.

Here it is anyway:

function dbRowsCount($sql, $data) {
    global $db, $query;
    $regex = '/^SELECT\s+(?:ALL\s+|DISTINCT\s+)?(?:.*?)\s+FROM\s+(.*)$/i';
    if (preg_match($regex, $sql, $output) > 0) {
        $query = $db->prepare("SELECT COUNT(*) FROM {$output[1]}");
        $query->setFetchMode(PDO::FETCH_NUM);
        if ($data != null)
            $query->execute($data);
        else
            $query->execute();
        if (!$query) {
            echo "Oops! There was an error: PDOStatement returned false.";
            exit;
        }
        return $query->fetchColumn();
    }
    return false;
}

So what’s gone wrong?

---

Edit

Here is some output from my program:
[Original Query]
[Query after regex]

SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(1) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(2) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(3) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(4) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(5) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(6) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(7) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(8) returned rows: 7
SELECT id, name FROM tbl_product_category INNER JOIN tbl_product_cat_basket AS basket ON id = basket.cat_id WHERE basket.product_id = ? LIMIT 0,1;
SELECT COUNT(*) FROM tbl_product_category

getProductCategory(9) returned rows: 7
SELECT * FROM tbl_store_admin WHERE php_sesskey=?;
SELECT COUNT(*) FROM tbl_store_admin WHERE php_sesskey=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_menu_cat_basket WHERE menu_id=?;
SELECT COUNT(*) FROM tbl_menu_cat_basket WHERE menu_id=?;

SELECT * FROM tbl_product ORDER BY last_update ASC;
SELECT COUNT(*) FROM tbl_product ORDER BY last_update ASC;

Answer 1

Your RegeExp doesn’t match, it’s missing the dot-all flag (/is in total).

This causes . to also match newlines in your string.