-- 回填 mch_manage.discounts_rate：
-- 从 discounts_price 文案（如"享9.5折"、"享菜品7.8折（不含酒水）"、"全场95折"）中提取"折"前面的数字，
-- 折算规则与 discounts_rate 语义(1-99，10=1折)一致：
--   小数或个位整数("9.5折"->95、"9折"->90、"0.5折"->5) 乘以10；
--   两位整数("95折")本身即百分比，保持原值 -> 95。
-- 仅填充 discounts_rate 为空的行，已配置的值不覆盖；提取不到"数字+折"或折算结果不在 1-99 的行跳过。

-- ① 预览：执行前先跑这条，人工确认折算结果
SELECT id, name, discounts_price,
       ROUND(CAST(REPLACE(REGEXP_SUBSTR(discounts_price, '[0-9]+(\\.[0-9]+)?折'), '折', '') AS DECIMAL(10, 2))
             * IF(CAST(REPLACE(REGEXP_SUBSTR(discounts_price, '[0-9]+(\\.[0-9]+)?折'), '折', '') AS DECIMAL(10, 2)) < 10, 10, 1)) AS will_rate
FROM mch_manage
WHERE discounts_rate IS NULL
  AND discounts_price REGEXP '[0-9]+(\\.[0-9]+)?折';

-- ② 执行回填
UPDATE mch_manage m
    JOIN (SELECT id,
                 ROUND(CAST(REPLACE(REGEXP_SUBSTR(discounts_price, '[0-9]+(\\.[0-9]+)?折'), '折', '') AS DECIMAL(10, 2))
                       * IF(CAST(REPLACE(REGEXP_SUBSTR(discounts_price, '[0-9]+(\\.[0-9]+)?折'), '折', '') AS DECIMAL(10, 2)) < 10,
                            10, 1)) AS rate
          FROM mch_manage
          WHERE discounts_rate IS NULL
            AND discounts_price REGEXP '[0-9]+(\\.[0-9]+)?折') t ON t.id = m.id
SET m.discounts_rate = t.rate
WHERE t.rate BETWEEN 1 AND 99;

-- ③ 核对：回填结果与原文对照
SELECT id, name, discounts_price, discounts_rate
FROM mch_manage
WHERE discounts_rate IS NOT NULL
ORDER BY update_time DESC;