問題場景
各大平臺店鋪的三項評分（物流、服務、商品）變化情況；
商品每日價格的變化記錄；
股票的實時漲跌??；
復現場景
表：主鍵ID，商品編號，記錄時的時間，記錄時的價格，創建時間。
問題：獲取每個商品每次的變化情況（漲跌幅、漲跌率）。
解決思路
1、要想高效率的更新漲跌，就肯定不能是逐條數據更新，要通過自連表建立起對應關系，將每一條數據關聯到上一次的價格數據。
2、由于數據庫非常龐大，所以可能存在很多垃圾數據，就比如說相關的字段值為NULL或者非有效值的，這些數據要先排除掉。
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、然后在獲取每條數據的上一條數據，同樣也要先排除掉垃圾數據。
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、獲取到上一條數據后，獲取上條數據對應的商品價格。
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、獲取到上條數據以及對應的價格后，開始進行計算，獲取到最終的結果。
SELECT
*,
(CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2))) AS '漲跌幅',
ROUND((CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2)))/CONVERT(last_price, DECIMAL(10,2)), 2) AS '漲跌率'
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
解決方案
-- 創建表SQL
CREATE TABLE `test_goods_price_change` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主鍵ID',
`goods_code` varchar(50) NOT NULL COMMENT '商品編碼',
`goods_date` int(11) NOT NULL COMMENT '記錄時的時間',
`goods_price` decimal(10,2) NOT NULL COMMENT '記錄時的價格',
`created_at` int(11) NOT NULL COMMENT '創建時間',
PRIMARY KEY (`id`)
) ENGINE=InnoDB CHARSET=utf8mb4;
-- 獲取漲跌浮SQL
SELECT
*,
(CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2))) AS '漲跌幅',
ROUND((CONVERT(goods_price, DECIMAL(10,2)) - CONVERT(last_price, DECIMAL(10,2)))/CONVERT(last_price, DECIMAL(10,2)), 2) AS '漲跌率'
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
到此這篇關于僅用一句SQL更新整張表的漲跌幅、漲跌率的文章就介紹到這了,更多相關SQL更新整張表內容請搜索腳本之家以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持腳本之家！
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