我正确的SQL查询(在phpmyadmin上测试)在PHP中返回错误的结果

Question

让我解释.我有一个简单的查询,当我在phpmyadmin上测试时,它可以工作,但它不会在我的Web应用程序中返回正确的答案.

这是运行查询的函数:

function GetProductsFromCategoryId($categoryId)
{
    global $db;
    $query = '
        SELECT *
        FROM `products`
        WHERE categoryID = 3';
    try {
        $statement = $db->prepare($query);
        //$statement->bindValue(':categoryId', $categoryId);
        $statement->execute();
        $result = $statement->fetch();
        $statement->closeCursor();
        return $result;
    } catch (PDOException $e) {
        $error_message = $e->getMessage();
        display_db_error($error_message);
    }
}

通常categoryID = $ categoryID,但我用"3"硬编码,因为我想看到结果.还有整个其他数据库文件处理连接,我可以发布它们,如果你想,但其他功能工作正常.这是我在Murach的php book ch 24中使用的模板.这个函数是我自己的,略有修改.

对于SELECT*,该函数应为每个产品返回2个数组,稍后当我从phpmyadmin发布结果时您会看到.相反,它只返回一个产品的1个数组.

这是我在phpmyadmin中运行的查询:

SELECT * FROM `products` WHERE categoryID=3;

结果是:

        9   3   ludwig  Ludwig 5-piece Drum Set with Cymbals    This product includes a Ludwig 5-piece drum set an...   699.99  30.00   2010-07-30 12:46:40
        10  3   tama    Tama 5-Piece Drum Set with Cymbals  The Tama 5-piece Drum Set is the most affordable T...   799.99  15.00   2010-07-30 13:14:15

所以,正如你所看到的,它应该返回2个数组,因为fetch()函数应该这样做,但它只返回一个数组.我有xdebug设置netbeans并查看变量$ result,它有1个数组,其中productName为"Ludwig 5-piece ......"

我已经坚持了3天,我不知道为什么它不起作用.请帮忙!

谢谢!!!

PS:这是数据库上表上的产品

        1   1   strat   Fender Stratocaster The Fender Stratocaster is the electric guitar des...   699.00  30.00   2009-10-30 09:32:40
        2   1   les_paul    Gibson Les Paul This Les Paul guitar offers a carved top and humbu...   1199.00 30.00   2009-12-05 16:33:13
        3   1   sg  Gibson SG   This Gibson SG electric guitar takes the best of t...   2517.00 52.00   2010-02-04 11:04:31
        4   1   fg700s  Yamaha FG700S   The Yamaha FG700S solid top acoustic guitar has th...   489.99  38.00   2010-06-01 11:12:59
        5   1   washburn    Washburn D10S   The Washburn D10S acoustic guitar is superbly craf...   299.00  0.00    2010-07-30 13:58:35
        6   1   rodriguez   Rodriguez Caballero 11  Featuring a carefully chosen, solid Canadian cedar...   415.00  39.00   2010-07-30 14:12:41
        7   2   precision   Fender Precision    The Fender Precision bass guitar delivers the soun...   799.99  30.00   2010-06-01 11:29:35
        8   2   hofner  Hofner Icon With authentic details inspired by the original, t...   499.99  25.00   2010-07-30 14:18:33
        9   3   ludwig  Ludwig 5-piece Drum Set with Cymbals    This product includes a Ludwig 5-piece drum set an...   699.99  30.00   2010-07-30 12:46:40
        10  3   tama    Tama 5-Piece Drum Set with Cymbals  The Tama 5-piece Drum Set is the most affordable T...   799.99  15.00   2010-07-30 13:14:15

第一列是productID,第二列是categoryID.

Answer 1

您$statement->fetch()只返回数据库中的一行.见PDOStatement::fetch().我想你想要PDOStatement::fetchAll()从查询中返回所有行.

Answer 2

PDOStatement :: fetch()一次只返回一行.您必须迭代调用它以获取剩余的行.