问题场景
各大平台店铺的三项评分（物流、服务、商品）变化情况；
商品每日价格的变化记录；
股票的实时涨跌浮；
复现场景
表：主键ID，商品编号，记录时的时间，记录时的价格，创建时间。
问题：获取每个商品每次的变化情况（涨跌幅、涨跌率）。
解决思路
1、要想高效率的更新涨跌，就肯定不能是逐条数据更新，要通过自连表建立起对应关系，将每一条数据关联到上一次的价格数据。
2、由于数据库非常庞大，所以可能存在很多垃圾数据，就比如说相关的字段值为NULL或者非有效值的，这些数据要先排除掉。
SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL;
3、然后在获取每条数据的上一条数据，同样也要先排除掉垃圾数据。
SELECT tmp_a.*, MAX(tmp_b.goods_date) AS last_date FROM
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_a
LEFT JOIN
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_b
ON tmp_a.goods_code = tmp_b.goods_code AND tmp_a.goods_date > tmp_b.goods_date GROUP BY tmp_a.id;
4、获取到上一条数据后，获取上条数据对应的商品价格。
SELECT tmp_ab.*,tmp_c.goods_price AS last_price FROM
(
SELECT tmp_a.*, MAX(tmp_b.goods_date) AS last_date FROM
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_a
LEFT JOIN
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_b
ON tmp_a.goods_code = tmp_b.goods_code AND tmp_a.goods_date > tmp_b.goods_date GROUP BY tmp_a.id
) AS tmp_ab
LEFT JOIN (SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_c
ON tmp_ab.goods_code = tmp_c.goods_code AND tmp_c.goods_date = tmp_ab.last_date ORDER BY tmp_ab.id;
5、获取到上条数据以及对应的价格后，开始进行计算，获取到最终的结果。
SELECT
*,
(CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2))) AS '涨跌幅',
ROUND((CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2)))/CONVERT(last_price, DECIMAL(10,2)), 2) AS '涨跌率'
FROM (
SELECT tmp_ab.*,tmp_c.goods_price AS last_price FROM
(
SELECT tmp_a.*, MAX(tmp_b.goods_date) AS last_date FROM
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_a
LEFT JOIN
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_b
ON tmp_a.goods_code = tmp_b.goods_code AND tmp_a.goods_date > tmp_b.goods_date GROUP BY tmp_a.id
) AS tmp_ab
LEFT JOIN (SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_c
ON tmp_ab.goods_code = tmp_c.goods_code AND tmp_c.goods_date = tmp_ab.last_date ORDER BY tmp_ab.id
) AS tmp
解决方案
-- 创建表SQL
CREATE TABLE `test_goods_price_change` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键ID',
`goods_code` varchar(50) NOT NULL COMMENT '商品编码',
`goods_date` int(11) NOT NULL COMMENT '记录时的时间',
`goods_price` decimal(10,2) NOT NULL COMMENT '记录时的价格',
`created_at` int(11) NOT NULL COMMENT '创建时间',
PRIMARY KEY (`id`)
) ENGINE=InnoDB CHARSET=utf8mb4;
-- 获取涨跌浮SQL
SELECT
*,
(CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2))) AS '涨跌幅',
ROUND((CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2)))/CONVERT(last_price, DECIMAL(10,2)), 2) AS '涨跌率'
FROM (
SELECT tmp_ab.*,tmp_c.goods_price AS last_price FROM
(
SELECT tmp_a.*, MAX(tmp_b.goods_date) AS last_date FROM
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_a
LEFT JOIN
( SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_b
ON tmp_a.goods_code = tmp_b.goods_code AND tmp_a.goods_date > tmp_b.goods_date GROUP BY tmp_a.id
) AS tmp_ab
LEFT JOIN (SELECT id,goods_code,goods_date,goods_price FROM test_goods_price_change WHERE goods_price IS NOT NULL AND goods_date IS NOT NULL ) AS tmp_c
ON tmp_ab.goods_code = tmp_c.goods_code AND tmp_c.goods_date = tmp_ab.last_date ORDER BY tmp_ab.id
) AS tmp
到此这篇关于仅用一句SQL更新整张表的涨跌幅、涨跌率的文章就介绍到这了,更多相关SQL更新整张表内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！
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