sqxp/docs/sql/migration_20260414_biz_client_cart_perf_indexes.sql

-- 购物车性能索引优化（首页快速加减、角标汇总）
-- 目的：降低 /api/mini/client/cart* 相关查询延迟，减少高频点击场景的数据库扫描。

SET NAMES utf8mb4;

-- 1) 客户购物车列表/汇总：WHERE client_id=? AND is_del=0
ALTER TABLE `biz_client_cart`
  ADD INDEX `idx_biz_client_cart_client_is_del` (`client_id`, `is_del`);

-- 2) 同商品合并与增量更新：WHERE client_id=? AND product_id=? AND price_list_id=? AND is_del=0
ALTER TABLE `biz_client_cart`
  ADD INDEX `idx_biz_client_cart_client_product_price_is_del` (`client_id`, `product_id`, `price_list_id`, `is_del`);