我认为添加这些列应该可以做到：
-- [params]
-- date :start_date
-- date :end_date
WITH staff_data AS (
SELECT user_id, true as is_staff
FROM group_users
WHERE group_id = 3
),
month_stats AS (
SELECT
date_trunc('month', p.created_at)::date AS month,
COUNT(*) FILTER (WHERE p.post_number = 1) AS total_topics,
COUNT(*) FILTER (WHERE p.post_number = 1 AND is_staff IS NOT TRUE) AS non_staff_topics,
COUNT(*) FILTER (WHERE p.post_number = 1 AND is_staff IS TRUE) AS staff_topics,
COUNT(*) FILTER (WHERE p.post_number <> 1) AS total_posts,
COUNT(DISTINCT p.user_id) FILTER (WHERE p.post_number <> 1 AND is_staff IS NOT TRUE) AS non_staff_users,
COUNT(*) FILTER (WHERE p.post_number <> 1 AND is_staff IS NOT TRUE) AS non_staff_posts,
COUNT(DISTINCT p.user_id) FILTER (WHERE p.post_number <> 1 AND is_staff) AS staff_users,
COUNT(*) FILTER (WHERE p.post_number <> 1 AND is_staff) AS staff_posts
FROM posts p
LEFT JOIN topics t ON t.id = p.topic_id
LEFT JOIN staff_data s ON p.user_id = s.user_id
WHERE p.created_at::date BETWEEN :start_date AND :end_date
AND t.archetype = 'regular'
AND t.deleted_at IS NULL
AND p.deleted_at IS NULL
AND p.post_type = 1
AND p.user_id > 0
GROUP BY month
)
SELECT
ms.month AS "月份",
ms.total_topics AS "所有主题",
ms.non_staff_topics AS "非员工主题",
ROUND(ms.non_staff_topics * 100.0 / NULLIF(ms.total_topics, 0),1) || '%' AS "非员工主题（占总数的 %）",
ms.staff_topics AS "员工主题",
ROUND(ms.staff_topics * 100.0 / NULLIF(ms.total_topics, 0),1) || '%' AS "员工主题（占总数的 %）",
ms.total_posts AS "所有帖子",
ms.non_staff_posts AS "非员工帖子",
ROUND(ms.non_staff_posts * 100.0 / NULLIF(ms.total_posts, 0),1) || '%' AS "非员工帖子（占总数的 %）",
ms.non_staff_posts / NULLIF(ms.total_topics, 0) AS "每个主题的平均非员工帖子数",
ms.non_staff_users AS "发帖的非员工用户数",
ms.staff_posts AS "员工帖子",
ROUND(ms.staff_posts * 100.0 / NULLIF(ms.total_posts, 0),1) || '%' AS "员工帖子（占总数的 %）",
ms.staff_posts / NULLIF(ms.total_topics, 0) AS "每个主题的平均员工帖子数",
ms.staff_users AS "发帖的员工用户数"
FROM month_stats ms
ORDER BY "月份"
