-- MySQL 5.7
-- 客户业务员存量迁移前分类清单（只读，不修改数据）。
-- 请先执行本文件，检查 ID/工号冲突，再执行 20261028_customer_sales_user_migration.sql。
-- 分类依据：精确匹配 sys_user.user_id；或按区分大小写的 sys_user.user_name 唯一匹配。

-- 分类汇总：VALID_USER_ID 保留；UNIQUE_USERNAME 可安全转换；其余分类写入冲突/未匹配清单。
SELECT classified.classification, COUNT(*) AS customer_count
FROM (
    SELECT c.customer_id,
           CASE
               WHEN c.sales_user_id IS NULL OR TRIM(c.sales_user_id) = '' THEN 'EMPTY'
               WHEN id_match.match_count > 0 AND name_match.match_count > 0 THEN 'ID_USERNAME_COLLISION'
               WHEN id_match.match_count > 0 THEN 'VALID_USER_ID'
               WHEN name_match.match_count = 1 THEN 'UNIQUE_USERNAME'
               WHEN name_match.match_count > 1 THEN 'AMBIGUOUS_USERNAME'
               ELSE 'NO_MATCH'
           END AS classification
    FROM ctr_customer c
    LEFT JOIN (
        SELECT CAST(user_id AS CHAR) AS lookup_value, COUNT(*) AS match_count
        FROM sys_user
        WHERE del_flag = '0'
        GROUP BY CAST(user_id AS CHAR)
    ) id_match ON BINARY id_match.lookup_value = BINARY TRIM(c.sales_user_id)
    LEFT JOIN (
        SELECT BINARY TRIM(user_name) AS lookup_value, COUNT(*) AS match_count
        FROM sys_user
        WHERE del_flag = '0'
          AND user_name IS NOT NULL
          AND user_name != ''
        GROUP BY BINARY TRIM(user_name)
    ) name_match ON name_match.lookup_value = BINARY TRIM(c.sales_user_id)
    WHERE c.del_flag = '0'
) classified
GROUP BY classified.classification
ORDER BY classified.classification;

-- 逐条分类。冲突项会列出原值、user_id 候选和 user_name 候选，供管理员人工核实。
SELECT c.customer_id,
       c.customer_code,
       c.customer_name,
       c.sales_user_id AS original_sales_user_id,
       CASE
           WHEN c.sales_user_id IS NULL OR TRIM(c.sales_user_id) = '' THEN 'EMPTY'
           WHEN id_match.match_count > 0 AND name_match.match_count > 0 THEN 'ID_USERNAME_COLLISION'
           WHEN id_match.match_count > 0 THEN 'VALID_USER_ID'
           WHEN name_match.match_count = 1 THEN 'UNIQUE_USERNAME'
           WHEN name_match.match_count > 1 THEN 'AMBIGUOUS_USERNAME'
           ELSE 'NO_MATCH'
       END AS classification,
       COALESCE(id_match.match_count, 0) AS user_id_match_count,
       COALESCE(name_match.match_count, 0) AS user_name_match_count,
       id_match.candidate_user_ids AS user_id_candidates,
       name_match.candidate_user_ids AS user_name_candidates
FROM ctr_customer c
LEFT JOIN (
    SELECT CAST(user_id AS CHAR) AS lookup_value,
           COUNT(*) AS match_count,
           GROUP_CONCAT(CAST(user_id AS CHAR) ORDER BY user_id SEPARATOR ',') AS candidate_user_ids
    FROM sys_user
    WHERE del_flag = '0'
    GROUP BY CAST(user_id AS CHAR)
) id_match ON BINARY id_match.lookup_value = BINARY TRIM(c.sales_user_id)
LEFT JOIN (
    SELECT BINARY TRIM(user_name) AS lookup_value,
           COUNT(*) AS match_count,
           GROUP_CONCAT(CAST(user_id AS CHAR) ORDER BY user_id SEPARATOR ',') AS candidate_user_ids
    FROM sys_user
    WHERE del_flag = '0'
      AND user_name IS NOT NULL
      AND user_name != ''
    GROUP BY BINARY TRIM(user_name)
) name_match ON name_match.lookup_value = BINARY TRIM(c.sales_user_id)
WHERE c.del_flag = '0'
ORDER BY classification, c.customer_id;