-- =============================================
-- 赋码管理 - 袋码表 bag_no 索引
-- selectMaxBagNo() 依赖 MAX(bag_no)；大批量生成后无索引会全表扫描
-- MySQL 8.4 适用
-- =============================================

SET NAMES utf8mb4;

SET @exists = (SELECT COUNT(*) FROM information_schema.statistics
               WHERE table_schema = DATABASE()
                 AND table_name = 'mes_pro_bag_code'
                 AND index_name = 'idx_bag_no');
SET @sql = IF(@exists = 0,
              'ALTER TABLE mes_pro_bag_code ADD INDEX idx_bag_no (bag_no)',
              'SELECT 1');
PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;