基於選擇值的SQL列

Question

希望通過一個查詢來獲取數據，但是列是動態的，基於選定的值。

所以我的表看起來像這樣（使用MySql）：

CREATE TABLE 'users' (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(45) NOT NULL
)

CREATE TABLE `income` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `timestamp` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `user` int(11) NOT NULL,
  `day` int(11) NOT NULL DEFAULT '0',
  `action_a` decimal(10,2) NOT NULL DEFAULT '0.00',
  `action_b` decimal(10,2) NOT NULL DEFAULT '0.00',
  `action_c` decimal(10,2) NOT NULL DEFAULT '0.00',
  PRIMARY KEY (`id`)
)

CREATE TABLE `given` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `timestamp` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `day` int(11) DEFAULT NULL,
  `to_user` int(11) NOT NULL,
  `from_user` int(11) NOT NULL,
  `amount` decimal(10,2) NOT NULL DEFAULT '0.00',
  PRIMARY KEY (`id`)
)

想進入一個看起來像這樣的查詢表：

+------------+--------------+----------+----------+----------+
| day | action_a | action_b | action_c | user_B   | user_C   |
+------------+--------------+----------+----------+----------+
| 123 | 123.01   | 123.01   | 123.01   |  123.01  | -123.01  |
| 122 | 324.02   | 234.01   | 123.01   | -123.01  | -123.01  |
| 121 | 987.00   | 345.01   | 123.01   |  123.01  | -123.01  |
| 120 | 9393.01  | 456.01   | 123.01   | -123.01  | -123.01  |
| 119 | 0.00     | 567.01   | 123.01   | -123.01  | -123.01  |
 ...

用戶列中的負值表示用戶已將其分配給其他用戶

當前，我正在執行3個單獨的查詢，然后合並數據，但是我當前的查詢如下所示：

獲得基於行動的收入

Select action_a, action_b, action_c From income i Join users u on u.id=i.user Where u.name='%s' and i.day=%i Order by i.id desc

得到好評

Select u2.name 'from', amount From given g Join users u on u.id = to_user Join users u2 on u2.id = from_user Where u.name='%s' and amount <> 0.0 Order by g.id 

得到給

Select u2.name 'to', amount From given g Join users u on u.id = from_user Join users u2 on u2.id = to_user Where u.name='%s' and amount <> 0.0 Order by g.id desc

SQLFiddle鏈接

Answer 1

歸一化的收入/收入表的示例如下：

CREATE TABLE income 
(income_id SERIAL PRIMARY KEY
,dt datetime NOT NULL DEFAULT CURRENT_TIMESTAMP
,user INT NOT NULL
);

CREATE TABLE income_action 
(income_id INT NOT NULL
,action CHAR(1) NOT NULL
,value DECIMAL(10,2) NOT NULL DEFAULT '0.00',
,PRIMARY KEY(income_id,action)
);