shanxia2.0/docs/sql/migrate_pl_plan_copy_seq_no_20261009.sql

-- 运输计划复制发群固定序号（租户内流水）
-- MySQL 5.7
-- 2026-10-09
-- 若列已存在，跳过 ALTER（重复执行会报 Duplicate column）。

ALTER TABLE `pl_plan`
  ADD COLUMN `copy_seq_no` int(11) DEFAULT NULL COMMENT '复制发群序号（租户内固定流水，首次复制时分配）' AFTER `plan_no`,
  ADD KEY `idx_pl_plan_tenant_copy_seq` (`tenant_no`, `copy_seq_no`);

-- 历史回填：按租户 create_time ASC, id ASC，含软删；已有值不覆盖
-- MySQL 5.7 用户变量按租户编号（会话内执行）
SET @prev_tenant := NULL;
SET @rn := 0;

UPDATE `pl_plan` p
INNER JOIN (
  SELECT
    t.id,
    t.seq_no
  FROM (
    SELECT
      id,
      tenant_no,
      @rn := IF(@prev_tenant = tenant_no, @rn + 1, 1) AS seq_no,
      @prev_tenant := tenant_no AS _tenant
    FROM (
      SELECT id, tenant_no, create_time
      FROM `pl_plan`
      ORDER BY tenant_no ASC, create_time ASC, id ASC
    ) ordered
  ) t
) ranked ON ranked.id = p.id
SET p.`copy_seq_no` = ranked.seq_no
WHERE p.`copy_seq_no` IS NULL;