Question

我正在尝试向我的数据库询问问题＆＃34;哪种股票格式最畅销？＆＃34;。下面是一些示例数据和构成数据库本身的代码。我使用phpMyadmin来创建数据库，所以这是来自Myadmin的数据转储。

CREATE TABLE IF NOT EXISTS `tbl_sale` (
`id_sale` int(11) NOT NULL AUTO_INCREMENT,
`id_stock` int(11) NOT NULL,
`id_customer` int(11) NOT NULL,
`id_employee` int(11) NOT NULL,
`id_invoice` int(11) NOT NULL,
PRIMARY KEY (`id_sale`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=32 ;

INSERT INTO `tbl_sale` (`id_sale`, `id_stock`,`id_customer`,`id_employee`, `id_invoice`) VALUES
(2, 2, 1, 1, 1),
(3, 1, 1, 1, 1),
(4, 3, 1, 1, 1),
(5, 4, 2, 2, 2),
(6, 5, 2, 2, 2),
(7, 6, 3, 3, 3),
(8, 7, 4, 4, 4),
(9, 8, 4, 5, 4),
(10, 9, 4, 5, 4),
(11, 10, 4, 6, 4),
(12, 11, 5, 7, 5),
(13, 12, 5, 7, 5),
(14, 13, 6, 8, 6),
(15, 14, 6, 8, 6),
(16, 15, 6, 8, 6),
(17, 16, 7, 9, 7),
(18, 17, 8, 10, 8),
(19, 18, 8, 10, 8),
(20, 19, 9, 1, 9),
(21, 20, 9, 1, 9),
(22, 21, 9, 1, 9),
(23, 22, 9, 1, 9),
(24, 1, 10, 2, 10),
(25, 2, 11, 3, 11),
(26, 3, 12, 4, 12),
(27, 4, 12, 4, 12),
(28, 5, 13, 5, 13),
(29, 6, 14, 6, 14),
(30, 7, 15, 7, 15),
(31, 8, 16, 7, 16);

 CREATE TABLE IF NOT EXISTS `tbl_stock` (
`id_stock` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(25) NOT NULL,
`quantity` int(11) NOT NULL,
`price_cost` decimal(10,2) NOT NULL,
`price_sale` decimal(10,2) NOT NULL,
`weight` int(25) NOT NULL,
`id_format` int(11) NOT NULL,
`id_genre` int(11) NOT NULL,
PRIMARY KEY (`id_stock`)
 ) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=23 ;

INSERT INTO `tbl_stock` (`id_stock`, `name`, `quantity`, `price_cost`,`price_sale`, `weight`, `id_format`, `id_genre`) VALUES
(1, 'Star Wars: The Force Awak', 10, 2.39, 10.00, 16, 1, 1),
(2, 'The Hunger Games: Mocking', 15, 2.28, 11.00, 16, 3, 2),
(3, 'Deadpool', 20, 4.00, 15.99, 16, 1, 14),
(4, 'The Jungle Book', 10, 1.78, 13.99, 16, 1, 1),
(5, 'Captain America: Civil Wa', 13, 2.59, 12.99, 16, 3, 1),
(6, 'Batman v Superman: Dawn o', 15, 2.99, 14.99, 16, 3, 14),
(7, 'The Huntsman: Winter''s Wa', 14, 2.99, 13.00, 16, 1, 5),
(8, 'The Magnificent Seven', 10, 1.36, 11.99, 16, 1, 16),
(9, 'Hardcore Henry', 5, 1.24, 10.99, 16, 3, 18),
(10, 'Doctor Strange', 8, 2.54, 14.99, 16, 1, 2),
(11, 'Power Rangers ', 9, 0.97, 13.99, 16, 3, 14),
(12, '10 Cloverfield Lane', 5, 1.34, 12.99, 16, 3, 10),
(13, 'Star Wars Battlefront', 10, 8.49, 29.50, 100, 6, 18),
(14, 'Quantum Break', 20, 15.78, 38.61, 100, 6, 18),
(15, 'Call of Duty: Black Ops I', 12, 9.89, 30.00, 100, 5, 18),
(16, 'One Voice', 5, 1.52, 9.99, 58, 2, 21),
(17, 'NOW That''s What I Call Mu', 3, 1.29, 13.00, 55, 2, 21),
(18, 'Ratchet and Clank', 10, 7.89, 28.00, 100, 6, 17),
(19, 'Uncharted 4: A Theif''s En', 10, 7.89, 44.00, 100, 6, 18),
(20, 'Dark Sould III', 10, 9.99, 38.99, 100, 5, 19),
(21, 'Grand Theft Auto V', 12, 11.99, 37.49, 100, 5, 20),
(22, 'FIFA 16', 7, 5.89, 34.95, 100, 6, 21);

CREATE TABLE IF NOT EXISTS `tbl_stock_format` (
`id_format` int(11) NOT NULL AUTO_INCREMENT,
`format` varchar(25) NOT NULL,
  PRIMARY KEY (`id_format`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=8 ;

INSERT INTO `tbl_stock_format` (`id_format`, `format`) VALUES
(1, 'DVD'),
(2, 'CD'),
(3, 'Blu-Ray'),
(4, 'Vinyl'),
(5, 'Playstation 4'),
(6, 'Xbox One');

我尝试使用的查询是：

SELECT id_format, MAX(MAX_COUNT)
FROM(
SELECT id_format, COUNT(id_format) AS MAX_COUNT
SELECT*FROM tbl_sale, tbl_stock_format
WHERE tbl_sale.id_format = tbl_stock_format.id_format
GROUP BY id_format) AS COUNT

但是你得到这个错误：

1064 - 您的SQL语法出错;检查与您的MySQL服务器版本相对应的手册，以便在＆＃39; SELECT * FROM tbl_sale，tbl_stock_format WHERE tbl_sale.id_format = tbl_stock_form＆＃39;附近使用正确的语法。在第4行

有人可以告诉我，我做错了吗？

Answer 1

这个查询充斥着废话。您选择的表列不属于表：tbl_sale.id_format，您有多个没有结构的选择查询。

尝试此查询。如果这没有输出正确的结果，那么它比你所展示的要好得多。

SELECT tbl_stock_format.id_format, tbl_stock_format.format, COUNT(tbl_stock_format.id_format) AS count
FROM tbl_stock_format 
INNER JOIN tbl_stock
ON tbl_stock.id_format = tbl_stock_format.id_format
INNER JOIN tbl_sale
ON tbl_sale.id_stock = tbl_stock.id_stock
GROUP BY tbl_stock_format.id_format
ORDER BY count DESC

查询最佳销售格式无法正常工作

1 个答案: