commit 3f3dc443da248ae6cb2619524a897577b2fbb48f
Author: chenwu <zhuchenwu@chenwuzhu.cn>
Date:   Thu Aug 20 18:22:16 2026 +0800

    refactor CHPA hierarchy SQL

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..e3208c6
--- /dev/null
+++ b/README.md
@@ -0,0 +1,54 @@
+# REFACTOR-MA
+
+Databricks 数仓 SQL 重构仓库。
+
+## 首批 review 范围
+
+本批次只重构原 `CHPA/01` 中两个层级维表脚本：
+
+- `sql/chpa/01_dwd/01_dwd_ims_atc_hierarchy.sql`
+- `sql/chpa/01_dwd/02_dwd_ims_nfc_hierarchy.sql`
+
+工作区 `CHPA/` 下的原脚本保持不变，便于逐项对照。
+
+## 兼容性决策
+
+首批代码继续写入现有物理表：
+
+- `dwd.dwd_ims_atc_hierarchy`
+- `dwd.dwd_ims_nfc_hierarchy`
+
+这样不会立即影响 pack property 和 DWS 等现有下游任务。推荐的新表名及迁移规则记录在 `docs/sql_refactoring_standard.md`；是否执行物理改名，待本批 review 后决定。
+
+## 目录结构
+
+```text
+RE/
+|-- README.md
+|-- docs/
+|   `-- sql_refactoring_standard.md
+|-- sql/
+|   `-- chpa/
+|       `-- 01_dwd/
+|           |-- 01_dwd_ims_atc_hierarchy.sql
+|           `-- 02_dwd_ims_nfc_hierarchy.sql
+`-- validation/
+    `-- chpa/
+        `-- 01_dwd/
+            `-- validate_hierarchy_refactor.sql
+```
+
+## 执行顺序
+
+1. 在覆盖目标表前运行 `validation/chpa/01_dwd/validate_hierarchy_refactor.sql`。
+2. 核对两个 `DESCRIBE TABLE` 结果；兼容性检查必须全部返回 `passed = true`。
+3. review 重复路径和未匹配层级指标，确认它们符合现有业务口径。
+4. 通过后，按文件名前缀顺序执行 `sql/chpa/01_dwd/` 中的重构脚本。
+
+两个重构脚本都要求现有 DWD 源表、目标表已经创建。
+
+## 本次 review 重点
+
+1. 表命名模型是否适用于整个数仓。
+2. 物理表改名采用兼容视图还是一次性联动下游。
+3. 替换调度任务前，在 Databricks 中对比新旧结果的行数、业务键重复数和空键数。
diff --git a/docs/sql_refactoring_standard.md b/docs/sql_refactoring_standard.md
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index 0000000..c841df9
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+++ b/docs/sql_refactoring_standard.md
@@ -0,0 +1,119 @@
+# Databricks SQL 重构规范
+
+## 1. 范围和原则
+
+本规范适用于 CHPA Databricks 数仓脚本。第一阶段目标是在不改变业务结果的前提下提高可维护性。
+
+- 先保持业务口径，再做性能优化。
+- 每个脚本只负责一个主要目标表。
+- 文件头声明源表、目标表、数据粒度、写入方式和依赖。
+- 持久化写入必须显式列出目标列和查询列，禁止使用 `SELECT *`。
+- 逻辑重构与生产表改名分开实施。
+- 为行数、唯一性、非空约束和未匹配记录建立验证查询或任务检查。
+
+## 2. 文件和目录命名
+
+目录结构统一为：
+
+```text
+sql/<业务域>/<阶段>/<序号>_<目标表>.sql
+```
+
+规则：
+
+- 目录和文件名使用小写 snake_case。
+- 路径和文件名不使用空格。
+- 使用两位序号明确 notebook/job 的执行顺序。
+- 一个脚本只写入一个主要持久化目标。像 `01 dwd_update.sql` 这种多目标脚本，应按目标表和职责拆分。
+
+示例：
+
+```text
+sql/chpa/01_dwd/01_dwd_ims_atc_hierarchy.sql
+```
+
+## 3. 物理表命名
+
+新表使用以下格式：
+
+```text
+[<catalog>.]<分层_schema>.<来源系统>_<对象类型>_<业务实体>[_<限定词>]
+```
+
+未启用 Unity Catalog 或依赖默认 catalog 时可以省略 catalog。分层已经由 schema 表达，表名不再重复 `dwd`、`dws` 或 `dm`。
+
+- 来源系统：如 `ims`、`gnd`、`pharbers`。
+- 对象类型：`td` 表示维度/主数据，`tf` 表示事实数据。
+- 业务实体：使用稳定的业务名词，如 `atc_hierarchy`、`pack_property`。
+- 限定词：按需表达粒度或变体，如 `monthly`、`province`。
+
+`01` 组表名建议：
+
+| 现有物理表名 | 推荐规范表名 | 首批处理方式 |
+| --- | --- | --- |
+| `dwd.dwd_ims_atc_hierarchy` | `dwd.ims_td_atc_hierarchy` | 保留现名 |
+| `dwd.dwd_ims_nfc_hierarchy` | `dwd.ims_td_nfc_hierarchy` | 保留现名 |
+| `dwd.dwd_ims_td_manufacturer_corp` | `dwd.ims_td_manufacturer_corporation` | 后续 review |
+| `dwd.dwd_ims_td_pack_property` | `dwd.ims_td_pack_property` | 后续 review |
+| `dwd.dwd_gnd_pharbers_prov_fact` | `dwd.pharbers_tf_province_sales` | 先确认业务粒度 |
+
+推荐迁移顺序：
+
+1. 创建规范名称的新表，并用兼容视图暴露旧表名。
+2. 新旧表并行运行，对比数据结果。
+3. 在一次受控发布中修改全部下游引用。
+4. 所有消费者迁移后再移除旧名称兼容视图。
+
+## 4. 字段命名
+
+- 新字段使用小写 snake_case。
+- 标识使用 `_id`，业务编码使用 `_code`，名称或描述使用 `_name`、`_description`。
+- 日期时间后缀按真实类型使用 `_date`、`_timestamp` 或 `_at`。
+- `atc`、`nfc`、`prod`、`pack` 等已形成业务共识或受输出契约约束的缩写可以保留。
+- 纯逻辑重构中不直接修改持久化输出字段名。
+
+## 5. SQL 结构和格式
+
+脚本统一按以下顺序组织：
+
+1. Databricks notebook 标记和脚本契约头。
+2. 带显式目标列的 `INSERT OVERWRITE`。
+3. 源数据标准化 CTE。
+4. 业务规则 CTE。
+5. 按目标表字段顺序显式编写最终 `SELECT`。
+
+格式规则：
+
+- SQL 关键字使用大写。
+- CTE 和别名使用小写 snake_case。
+- 使用四个空格缩进。
+- `SELECT` 每行一个字段。
+- 每个 JOIN 条件单独成行。
+- 使用 `atc_level_1` 等有业务意义的别名，维护代码中不使用 `t1`、`a` 等无语义别名。
+- 同一作用域出现多个关系时，所有字段都带关系限定符。
+
+## 6. 写入和数据质量规则
+
+- 只有可确定性重跑的全量任务可以使用 `INSERT OVERWRITE`。
+- 不在一个脚本中混合无关的 `UPDATE` 和目标表构建逻辑。
+- 编码补零等标准化逻辑集中到一个明确的处理阶段，避免在多个任务中重复表达式。
+- 每个脚本必须声明预期目标粒度。
+- 最少验证以下指标：
+  - 新结果与旧结果的总行数；
+  - 声明业务键的重复数；
+  - 必填键的空值数；
+  - 层级关联新增的未匹配记录数。
+
+## 7. 首批兼容说明
+
+ATC 和 NFC 脚本原样保留以下父级编码规则：
+
+- ATC 2 级关联 1 级：取前 1 位。
+- ATC 3 级关联 2 级：取前 3 位。
+- ATC 4 级关联 3 级：取前 4 位。
+- NFC 2 级关联 1 级：取前 1 位。
+- NFC 3 级关联 2 级：取前 2 位。
+
+任何口径简化都应先用生产样本验证这些规则。
+
+首批上线前运行 `validation/chpa/01_dwd/validate_hierarchy_refactor.sql`。新旧双向差集必须为 0，行数必须一致；重复路径和未匹配层级作为业务 review 指标记录，不在未确认阈值前自动判定失败。
diff --git a/sql/chpa/01_dwd/01_dwd_ims_atc_hierarchy.sql b/sql/chpa/01_dwd/01_dwd_ims_atc_hierarchy.sql
new file mode 100644
index 0000000..558fe43
--- /dev/null
+++ b/sql/chpa/01_dwd/01_dwd_ims_atc_hierarchy.sql
@@ -0,0 +1,86 @@
+-- Databricks notebook source
+-- =============================================================================
+-- Purpose    : Build the flattened IMS ATC level 1-4 hierarchy.
+-- Source     : dwd.dwd_ims_td_therapeutic_class
+-- Target     : dwd.dwd_ims_atc_hierarchy
+-- Grain      : One row per hierarchy path rooted at ATC1_CODE; lower levels may be null.
+-- Write mode : Full refresh (INSERT OVERWRITE).
+-- Downstream : dwd.dwd_ims_td_pack_property, dws.dws_ims_td_atc_cn
+-- Notes      : Parent-code matching is preserved from the legacy script.
+-- =============================================================================
+
+INSERT OVERWRITE TABLE dwd.dwd_ims_atc_hierarchy (
+    ATC1_ID,
+    ATC1_CODE,
+    ATC1_DES,
+    ATC2_ID,
+    ATC2_CODE,
+    ATC2_DES,
+    ATC3_ID,
+    ATC3_CODE,
+    ATC3_DES,
+    ATC4_ID,
+    ATC4_CODE,
+    ATC4_DES
+)
+WITH therapeutic_class AS (
+    SELECT
+        therapeutic_id,
+        therapeutic_code,
+        therapeutic_name,
+        therapeutic_level
+    FROM dwd.dwd_ims_td_therapeutic_class
+),
+atc_level_1 AS (
+    SELECT
+        therapeutic_id AS atc1_id,
+        therapeutic_code AS atc1_code,
+        therapeutic_name AS atc1_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '1'
+),
+atc_level_2 AS (
+    SELECT
+        therapeutic_id AS atc2_id,
+        therapeutic_code AS atc2_code,
+        therapeutic_name AS atc2_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '2'
+),
+atc_level_3 AS (
+    SELECT
+        therapeutic_id AS atc3_id,
+        therapeutic_code AS atc3_code,
+        therapeutic_name AS atc3_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '3'
+),
+atc_level_4 AS (
+    SELECT
+        therapeutic_id AS atc4_id,
+        therapeutic_code AS atc4_code,
+        therapeutic_name AS atc4_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '4'
+)
+SELECT
+    atc_level_1.atc1_id,
+    atc_level_1.atc1_code,
+    atc_level_1.atc1_des,
+    atc_level_2.atc2_id,
+    atc_level_2.atc2_code,
+    atc_level_2.atc2_des,
+    atc_level_3.atc3_id,
+    atc_level_3.atc3_code,
+    atc_level_3.atc3_des,
+    atc_level_4.atc4_id,
+    atc_level_4.atc4_code,
+    atc_level_4.atc4_des
+FROM atc_level_1
+LEFT JOIN atc_level_2
+    ON atc_level_1.atc1_code = LEFT(atc_level_2.atc2_code, 1)
+LEFT JOIN atc_level_3
+    ON atc_level_2.atc2_code = LEFT(atc_level_3.atc3_code, 3)
+LEFT JOIN atc_level_4
+    ON atc_level_3.atc3_code = LEFT(atc_level_4.atc4_code, 4)
+;
diff --git a/sql/chpa/01_dwd/02_dwd_ims_nfc_hierarchy.sql b/sql/chpa/01_dwd/02_dwd_ims_nfc_hierarchy.sql
new file mode 100644
index 0000000..cbc81ce
--- /dev/null
+++ b/sql/chpa/01_dwd/02_dwd_ims_nfc_hierarchy.sql
@@ -0,0 +1,70 @@
+-- Databricks notebook source
+-- =============================================================================
+-- Purpose    : Build the flattened IMS NFC level 1-3 hierarchy.
+-- Source     : dwd.dwd_ims_td_new_form_class
+-- Target     : dwd.dwd_ims_nfc_hierarchy
+-- Grain      : One row per hierarchy path rooted at NFC1_CODE; lower levels may be null.
+-- Write mode : Full refresh (INSERT OVERWRITE).
+-- Downstream : dwd.dwd_ims_td_pack_property, dws.dws_ims_td_nfc_cn
+-- Notes      : Parent-code matching is preserved from the legacy script.
+-- =============================================================================
+
+INSERT OVERWRITE TABLE dwd.dwd_ims_nfc_hierarchy (
+    NFC1_ID,
+    NFC1_CODE,
+    NFC1_DES,
+    NFC2_ID,
+    NFC2_CODE,
+    NFC2_DES,
+    NFC3_ID,
+    NFC3_CODE,
+    NFC3_DES
+)
+WITH new_form_class AS (
+    SELECT
+        newformclass_id,
+        newformclass_code,
+        newformclass_name,
+        newformclass_level
+    FROM dwd.dwd_ims_td_new_form_class
+),
+nfc_level_1 AS (
+    SELECT
+        newformclass_id AS nfc1_id,
+        newformclass_code AS nfc1_code,
+        newformclass_name AS nfc1_des
+    FROM new_form_class
+    WHERE newformclass_level = '1'
+),
+nfc_level_2 AS (
+    SELECT
+        newformclass_id AS nfc2_id,
+        newformclass_code AS nfc2_code,
+        newformclass_name AS nfc2_des
+    FROM new_form_class
+    WHERE newformclass_level = '2'
+),
+nfc_level_3 AS (
+    SELECT
+        newformclass_id AS nfc3_id,
+        newformclass_code AS nfc3_code,
+        newformclass_name AS nfc3_des
+    FROM new_form_class
+    WHERE newformclass_level = '3'
+)
+SELECT
+    nfc_level_1.nfc1_id,
+    nfc_level_1.nfc1_code,
+    nfc_level_1.nfc1_des,
+    nfc_level_2.nfc2_id,
+    nfc_level_2.nfc2_code,
+    nfc_level_2.nfc2_des,
+    nfc_level_3.nfc3_id,
+    nfc_level_3.nfc3_code,
+    nfc_level_3.nfc3_des
+FROM nfc_level_1
+LEFT JOIN nfc_level_2
+    ON nfc_level_1.nfc1_code = LEFT(nfc_level_2.nfc2_code, 1)
+LEFT JOIN nfc_level_3
+    ON nfc_level_2.nfc2_code = LEFT(nfc_level_3.nfc3_code, 2)
+;
diff --git a/validation/chpa/01_dwd/validate_hierarchy_refactor.sql b/validation/chpa/01_dwd/validate_hierarchy_refactor.sql
new file mode 100644
index 0000000..6983f97
--- /dev/null
+++ b/validation/chpa/01_dwd/validate_hierarchy_refactor.sql
@@ -0,0 +1,263 @@
+-- Databricks notebook source
+-- MAGIC %md
+-- MAGIC # ATC/NFC hierarchy refactor validation
+-- MAGIC Run this notebook before executing the refactored overwrite scripts.
+-- MAGIC The legacy targets and source tables must represent the same data snapshot.
+
+-- COMMAND ----------
+
+-- Confirm the ATC target contains the expected 12 non-partition output columns.
+DESCRIBE TABLE dwd.dwd_ims_atc_hierarchy;
+
+-- COMMAND ----------
+
+-- Confirm the NFC target contains the expected 9 non-partition output columns.
+DESCRIBE TABLE dwd.dwd_ims_nfc_hierarchy;
+
+-- COMMAND ----------
+
+CREATE OR REPLACE TEMP VIEW validation_atc_hierarchy_candidate AS
+WITH therapeutic_class AS (
+    SELECT
+        therapeutic_id,
+        therapeutic_code,
+        therapeutic_name,
+        therapeutic_level
+    FROM dwd.dwd_ims_td_therapeutic_class
+),
+atc_level_1 AS (
+    SELECT
+        therapeutic_id AS atc1_id,
+        therapeutic_code AS atc1_code,
+        therapeutic_name AS atc1_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '1'
+),
+atc_level_2 AS (
+    SELECT
+        therapeutic_id AS atc2_id,
+        therapeutic_code AS atc2_code,
+        therapeutic_name AS atc2_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '2'
+),
+atc_level_3 AS (
+    SELECT
+        therapeutic_id AS atc3_id,
+        therapeutic_code AS atc3_code,
+        therapeutic_name AS atc3_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '3'
+),
+atc_level_4 AS (
+    SELECT
+        therapeutic_id AS atc4_id,
+        therapeutic_code AS atc4_code,
+        therapeutic_name AS atc4_des
+    FROM therapeutic_class
+    WHERE therapeutic_level = '4'
+)
+SELECT
+    atc_level_1.atc1_id AS ATC1_ID,
+    atc_level_1.atc1_code AS ATC1_CODE,
+    atc_level_1.atc1_des AS ATC1_DES,
+    atc_level_2.atc2_id AS ATC2_ID,
+    atc_level_2.atc2_code AS ATC2_CODE,
+    atc_level_2.atc2_des AS ATC2_DES,
+    atc_level_3.atc3_id AS ATC3_ID,
+    atc_level_3.atc3_code AS ATC3_CODE,
+    atc_level_3.atc3_des AS ATC3_DES,
+    atc_level_4.atc4_id AS ATC4_ID,
+    atc_level_4.atc4_code AS ATC4_CODE,
+    atc_level_4.atc4_des AS ATC4_DES
+FROM atc_level_1
+LEFT JOIN atc_level_2
+    ON atc_level_1.atc1_code = LEFT(atc_level_2.atc2_code, 1)
+LEFT JOIN atc_level_3
+    ON atc_level_2.atc2_code = LEFT(atc_level_3.atc3_code, 3)
+LEFT JOIN atc_level_4
+    ON atc_level_3.atc3_code = LEFT(atc_level_4.atc4_code, 4)
+;
+
+-- COMMAND ----------
+
+CREATE OR REPLACE TEMP VIEW validation_nfc_hierarchy_candidate AS
+WITH new_form_class AS (
+    SELECT
+        newformclass_id,
+        newformclass_code,
+        newformclass_name,
+        newformclass_level
+    FROM dwd.dwd_ims_td_new_form_class
+),
+nfc_level_1 AS (
+    SELECT
+        newformclass_id AS nfc1_id,
+        newformclass_code AS nfc1_code,
+        newformclass_name AS nfc1_des
+    FROM new_form_class
+    WHERE newformclass_level = '1'
+),
+nfc_level_2 AS (
+    SELECT
+        newformclass_id AS nfc2_id,
+        newformclass_code AS nfc2_code,
+        newformclass_name AS nfc2_des
+    FROM new_form_class
+    WHERE newformclass_level = '2'
+),
+nfc_level_3 AS (
+    SELECT
+        newformclass_id AS nfc3_id,
+        newformclass_code AS nfc3_code,
+        newformclass_name AS nfc3_des
+    FROM new_form_class
+    WHERE newformclass_level = '3'
+)
+SELECT
+    nfc_level_1.nfc1_id AS NFC1_ID,
+    nfc_level_1.nfc1_code AS NFC1_CODE,
+    nfc_level_1.nfc1_des AS NFC1_DES,
+    nfc_level_2.nfc2_id AS NFC2_ID,
+    nfc_level_2.nfc2_code AS NFC2_CODE,
+    nfc_level_2.nfc2_des AS NFC2_DES,
+    nfc_level_3.nfc3_id AS NFC3_ID,
+    nfc_level_3.nfc3_code AS NFC3_CODE,
+    nfc_level_3.nfc3_des AS NFC3_DES
+FROM nfc_level_1
+LEFT JOIN nfc_level_2
+    ON nfc_level_1.nfc1_code = LEFT(nfc_level_2.nfc2_code, 1)
+LEFT JOIN nfc_level_3
+    ON nfc_level_2.nfc2_code = LEFT(nfc_level_3.nfc3_code, 2)
+;
+
+-- COMMAND ----------
+
+-- Every check must return passed = true before replacing the scheduled jobs.
+WITH compatibility_checks AS (
+    SELECT
+        'atc_row_count' AS check_name,
+        (SELECT COUNT(*) FROM validation_atc_hierarchy_candidate) AS actual_value,
+        (SELECT COUNT(*) FROM dwd.dwd_ims_atc_hierarchy) AS expected_value
+    UNION ALL
+    SELECT
+        'atc_legacy_minus_candidate' AS check_name,
+        (
+            SELECT COUNT(*)
+            FROM (
+                SELECT * FROM dwd.dwd_ims_atc_hierarchy
+                EXCEPT ALL
+                SELECT * FROM validation_atc_hierarchy_candidate
+            ) AS differences
+        ) AS actual_value,
+        0 AS expected_value
+    UNION ALL
+    SELECT
+        'atc_candidate_minus_legacy' AS check_name,
+        (
+            SELECT COUNT(*)
+            FROM (
+                SELECT * FROM validation_atc_hierarchy_candidate
+                EXCEPT ALL
+                SELECT * FROM dwd.dwd_ims_atc_hierarchy
+            ) AS differences
+        ) AS actual_value,
+        0 AS expected_value
+    UNION ALL
+    SELECT
+        'nfc_row_count' AS check_name,
+        (SELECT COUNT(*) FROM validation_nfc_hierarchy_candidate) AS actual_value,
+        (SELECT COUNT(*) FROM dwd.dwd_ims_nfc_hierarchy) AS expected_value
+    UNION ALL
+    SELECT
+        'nfc_legacy_minus_candidate' AS check_name,
+        (
+            SELECT COUNT(*)
+            FROM (
+                SELECT * FROM dwd.dwd_ims_nfc_hierarchy
+                EXCEPT ALL
+                SELECT * FROM validation_nfc_hierarchy_candidate
+            ) AS differences
+        ) AS actual_value,
+        0 AS expected_value
+    UNION ALL
+    SELECT
+        'nfc_candidate_minus_legacy' AS check_name,
+        (
+            SELECT COUNT(*)
+            FROM (
+                SELECT * FROM validation_nfc_hierarchy_candidate
+                EXCEPT ALL
+                SELECT * FROM dwd.dwd_ims_nfc_hierarchy
+            ) AS differences
+        ) AS actual_value,
+        0 AS expected_value
+)
+SELECT
+    check_name,
+    actual_value,
+    expected_value,
+    actual_value = expected_value AS passed
+FROM compatibility_checks
+ORDER BY check_name;
+
+-- COMMAND ----------
+
+-- Profile duplicates and unmatched levels. These are review metrics, not automatic failures.
+WITH atc_duplicate_paths AS (
+    SELECT COUNT(*) AS path_count
+    FROM validation_atc_hierarchy_candidate
+    GROUP BY ATC1_CODE, ATC2_CODE, ATC3_CODE, ATC4_CODE
+    HAVING COUNT(*) > 1
+),
+nfc_duplicate_paths AS (
+    SELECT COUNT(*) AS path_count
+    FROM validation_nfc_hierarchy_candidate
+    GROUP BY NFC1_CODE, NFC2_CODE, NFC3_CODE
+    HAVING COUNT(*) > 1
+)
+SELECT
+    'atc_duplicate_path_rows' AS metric_name,
+    COALESCE(SUM(path_count - 1), 0) AS metric_value
+FROM atc_duplicate_paths
+UNION ALL
+SELECT
+    'atc_null_root_code' AS metric_name,
+    COUNT_IF(ATC1_CODE IS NULL) AS metric_value
+FROM validation_atc_hierarchy_candidate
+UNION ALL
+SELECT
+    'atc_unmatched_level_2' AS metric_name,
+    COUNT_IF(ATC2_CODE IS NULL) AS metric_value
+FROM validation_atc_hierarchy_candidate
+UNION ALL
+SELECT
+    'atc_unmatched_level_3' AS metric_name,
+    COUNT_IF(ATC3_CODE IS NULL) AS metric_value
+FROM validation_atc_hierarchy_candidate
+UNION ALL
+SELECT
+    'atc_unmatched_level_4' AS metric_name,
+    COUNT_IF(ATC4_CODE IS NULL) AS metric_value
+FROM validation_atc_hierarchy_candidate
+UNION ALL
+SELECT
+    'nfc_duplicate_path_rows' AS metric_name,
+    COALESCE(SUM(path_count - 1), 0) AS metric_value
+FROM nfc_duplicate_paths
+UNION ALL
+SELECT
+    'nfc_null_root_code' AS metric_name,
+    COUNT_IF(NFC1_CODE IS NULL) AS metric_value
+FROM validation_nfc_hierarchy_candidate
+UNION ALL
+SELECT
+    'nfc_unmatched_level_2' AS metric_name,
+    COUNT_IF(NFC2_CODE IS NULL) AS metric_value
+FROM validation_nfc_hierarchy_candidate
+UNION ALL
+SELECT
+    'nfc_unmatched_level_3' AS metric_name,
+    COUNT_IF(NFC3_CODE IS NULL) AS metric_value
+FROM validation_nfc_hierarchy_candidate
+ORDER BY metric_name;