看起来您希望total列表示给定 parent_id 是的，这和计数是一致的 parent_id 价值观。您可以尝试连接到查找计数的子查询：

SELECT
    t1.id_article,
    t1.parent_id,
    COALESCE(t2.Total, 0) AS Total
FROM t_article t1
LEFT JOIN
(
    SELECT parent_id, COUNT(*) AS Total
    FROM t_article
    WHERE parent_id <> 0
    GROUP BY parent_id
) t2
    ON t1.parent_id = t2.parent_id;

演示

下面是另一种使用内部连接和条件聚合的方法

select a.*, b.cnt
from t_article a
join (
  select parent_id, sum(parent_id <> 0) cnt
  from t_article 
  group by parent_id
) b using(parent_id)

演示

也可以使用子查询：

SELECT id_article,parent_id,(SELECT COUNT(parent_id) FROM t_article as t2  WHERE t2.parent_id = t1.parent_id AND t2.parent_id != 0 ) AS total  FROM `t_article` as  t1

结果