这种看似简单的任务,但我想我不知道在互联网上找到它的正确用语。
我想要的只是这个:
SELECT SUM(price) FROM products WHERE id IN (5, 10, 10, 10, 13, 15, 18, 18);
这基本上会让我回复:
price_of_5 + price_of_10 + price_of_10 + price_of_10 +
price_of_13 + price_of_15 + price_of_18 + price_of_18
也就是说,概念是 SELECT 与 IN 子句中指定的行完全一样,即使多次指定了一个值。
这是一个简单的测试环境(or a fiddle)
1-创建表
CREATE TABLE products (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(200) NOT NULL,
`price` float NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
2-喂桌子
INSERT INTO products VALUES (1, 'Apple', 5), (2, 'Orange', 6), (3, 'Grape', 10), (4, 'Watermelon', 20), (5, 'Cashew', 7);
3-我想要的例子:
SELECT SUM(price) FROM products WHERE id IN (1, 2, 2, 4);
结果:31(5 + 6 + 20)
预期:37(5 + 6 + 6 + 20)
答案 0 :(得分:3)
这是我的方法:
SELECT SUM(p.price)
FROM (
SELECT 5 id
UNION ALL
SELECT 10
UNION ALL
SELECT 10
UNION ALL
SELECT 10
UNION ALL
SELECT 13
UNION ALL
SELECT 15
UNION ALL
SELECT 18
UNION ALL
SELECT 18
) as t
INNER JOIN products p
ON t.id = p.id;
更新根据您提供的数据示例和小提琴,您可以针对您的案例转换查询:
http://sqlfiddle.com/#!9/189bc/4
SELECT SUM(p.price)
FROM (
SELECT 1 id
UNION ALL
SELECT 2
UNION ALL
SELECT 2
UNION ALL
SELECT 4
) as t
INNER JOIN products p
ON t.id = p.id;