请查看http://sqlfiddle.com/#!9/3a4d84/1/0
我有这张桌子
CREATE TABLE IF NOT EXISTS `data` (
`id` int(11) NOT NULL,
`mdate` char(10) DEFAULT NULL,
`customer_id` int(11) NOT NULL,
`category` varchar(64) NOT NULL,
`quantity` double NOT NULL,
`sales` double NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO `data` (`id`, `mdate`, `customer_id`, `category`, `quantity`, `sales`) VALUES
(2, '2015-02-01', 10720, 'Category1', 84.35, 894.24),
(3, '2015-01-02', 15570, 'Category1', 1000, 1325),
(4, '2015-01-02', 15570, 'Category6', 1000, 1325),
(5, '2015-01-05', 17090, 'Category1', 9600, 11671.76),
(6, '2015-01-05', 10360, 'Category2', 12110, 3981.6),
(7, '2015-01-05', 10360, 'Category1', 10150, 4828.95),
(8, '2015-01-06', 16460, 'Category3', 24000, 19656),
(9, '2015-01-05', 18260, 'Category3', 24000, 17688),
(10, '2015-01-05', 18260, 'Category2', 25200, 8129.02),
(11, '2015-01-05', 12570, 'Category1', 500, 6833.5),
(12, '2015-01-05', 11360, 'Category1', 2000, 1000),
(13, '2015-01-05', 11360, 'Category6', 23700, 8977.5),
(14, '2015-01-05', 15740, 'Category2', 26320, 9738.4),
(15, '2015-01-05', 10170, 'Category2', 24720, 9994.79),
(16, '2015-01-05', 12220, 'Category1', 4000, 2120),
(17, '2015-01-05', 13380, 'Category4', 24000, 44880),
(18, '2015-01-08', 13420, 'Category1', 23959, 23479.82),
(19, '2015-01-06', 10310, 'Category2', 24900, 13310.54),
(20, '2015-01-06', 17090, 'Category1', 6100, 2440),
(21, '2015-01-06', 17090, 'Category2', 2000, 1020),
(22, '2015-01-06', 17090, 'Category3', 2980, 1281.4),
(23, '2015-01-06', 17090, 'Category4', 2000, 1707.48),
(24, '2015-01-06', 10170, 'Category2', 25560, 12141),
(25, '2015-01-06', 13060, 'Category2', 24440, 9238.32),
(26, '2015-01-06', 10450, 'Category1', 3000, 2571.07),
(27, '2015-01-06', 11800, 'Category5', 9000, 163800),
(28, '2015-01-06', 18260, 'Category2', 25560, 8245.14),
(29, '2015-01-06', 10170, 'Category2', 25180, 11960.5),
(30, '2015-01-07', 10280, 'Category3', 21980, 16441.04),
(31, '2015-01-06', 19230, 'Category2', 17760, 9835.98),
(32, '2015-01-06', 19470, 'Category1', 6005, 13211),
(33, '2015-01-06', 18640, 'Category5', 1000, 18200),
(34, '2015-01-07', 10170, 'Category2', 26060, 12378.5),
(35, '2015-01-07', 18640, 'Category5', 1000, 18200),
(36, '2015-01-07', 13880, 'Category5', 500, 2303.93),
(37, '2015-01-07', 18260, 'Category2', 25360, 8180.63),
(38, '2015-01-05', 17040, 'Category2', 25080, 10784.4),
(39, '2015-01-02', 17040, 'Category2', 23340, 10036.2),
(40, '2015-01-02', 17040, 'Category3', 25500, 10965),
(41, '2015-01-02', 17040, 'Category7', 24960, 10732.8),
(42, '2015-01-08', 10720, 'Category1', 25000, 22375),
(43, '2015-01-07', 10680, 'Category1', 1000, 695),
(44, '2015-01-08', 16460, 'Category3', 24000, 20136),
(45, '2015-01-06', 10130, 'Category6', 500, 2950),
(46, '2015-01-08', 13880, 'Category2', 24000, 41280),
(47, '2015-01-07', 15180, 'Category3', 2000, 2500),
(48, '2015-01-06', 11060, 'Category3', 22000, 18480),
(49, '2015-01-06', 19450, 'Category6', 2000, 11400),
(50, '2015-01-07', 18150, 'Category4', 19748, 34756.48),
(51, '2015-01-06', 18690, 'Category1', 1000, 13128.98);
当我使用此查询时
SELECT
customer_id,
category,
sum(quantity) as quantity,
sum(sales) as sales
FROM `data`
GROUP BY customer_id, category
我得到这样的结果
customer_id category quantity sales
10130 Category6 500 2950
10170 Category2 101520 46474.79
10280 Category3 21980 16441.04
10310 Category2 24900 13310.54
10360 Category1 10150 4828.95
...
然后使用PHP，我构建了一个这样的表
| Category1 | Category2 | Category3
| quantity | sales | quantity | sales | quantity | sales ...
------+----------+-------+----------+-------+----------+--------------
10360 | 10150 | 4828 | | | |
10310 | | | 24900 | 13310 | |
1890 | 80150 | 9828 | | | 84822 | 2310
因此，您可以在一行中看到一个客户的每个类别的数量和销售额。 但现在我无法对表格进行排序......例如在“Category1数量”之后。
我想构建一个mysql查询来获取此格式（“Category1 quantity”， “Category1销售”，“Category2数量”，“Category2销售”......）直接为每个 顾客。所以我可以按顺序排序表...
有可能吗？我不太清楚如何实现它。也许我可以 找到这个Distinct（）所有类别并使用php和构建查询 许多子选择......或？
非常感谢你。最诚挚的问候
更新，现在我有这个'恐怖'查询
SELECT
e.customer_id,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category1' AND s.customer_id = e.customer_id) as quantity1,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category1' AND s.customer_id = e.customer_id) as sales1,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category2' AND s.customer_id = e.customer_id) as quantity2,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category2' AND s.customer_id = e.customer_id) as sales2,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category3' AND s.customer_id = e.customer_id) as quantity3,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category3' AND s.customer_id = e.customer_id) as sales3,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category4' AND s.customer_id = e.customer_id) as quantity4,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category4' AND s.customer_id = e.customer_id) as sales4,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category5' AND s.customer_id = e.customer_id) as quantity5,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category5' AND s.customer_id = e.customer_id) as sales5,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category6' AND s.customer_id = e.customer_id) as quantity6,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category6' AND s.customer_id = e.customer_id) as sales6,
(SELECT SUM(s.quantity) FROM `data` as s WHERE s.category = 'Category7' AND s.customer_id = e.customer_id) as quantity7,
(SELECT SUM(s.sales) FROM `data` as s WHERE s.category = 'Category7' AND s.customer_id = e.customer_id) as sales7
FROM `data` as e
Group by e.customer_id
Order by quantity1
有可能避免这种情况吗？ :)谢谢
答案 0 :(得分：0)
据我了解，您正在尝试将表格转换为category行值。不幸的是，MySQL没有这样的功能（比如T-SQL）。然而，这是一个常见的问题，并且很好地讨论了here。所以我会使用CASE而不是像这样的子查询重写您的查询：
SELECT
e.customer_id,
(SUM(CASE WHEN e.category = 'Category1' THEN e.quantity END)) as quantity1,
(SUM(CASE WHEN e.category = 'Category1' THEN e.sales END)) as sales1,
(SUM(CASE WHEN e.category = 'Category2' THEN e.quantity END)) as quantity2,
(SUM(CASE WHEN e.category = 'Category2' THEN e.sales END)) as sales2,
(SUM(CASE WHEN e.category = 'Category3' THEN e.quantity END)) as quantity3,
(SUM(CASE WHEN e.category = 'Category3' THEN e.sales END)) as sales3,
(SUM(CASE WHEN e.category = 'Category4' THEN e.quantity END)) as quantity4,
(SUM(CASE WHEN e.category = 'Category4' THEN e.sales END)) as sales4
# and so on
FROM `data` as e
Group by e.customer_id
Order by quantity1