使用mysql计算总计数的百分比

我想制作另一个sum数组（从count开始）。然后计算它旁边的百分比。于是我写道：

select vwr_cntry, COUNT(vwr_id) as count1 from viewer_log
where not vwr_cntry = ''
group by vwr_cntry

Union all

select 'SUM'
vwr_cntry, COUNT(count1)//cannot count the 'count1'

from viewer_log
order by count desc
limit 5

这个想法是列出前五名游客的国家，并计算每个国家的百分比（vwr_cntry）。我期待这样的事情：

+---------------+---------+-----+
|   Country     |count    |  %  |
+---------------+---------+-----+
|Thailand       |2314     |     |
+---------------+---------+-----+
|United States  |957      |     |
+---------------+---------+-----+
|Japan          |645      |     |
+---------------+---------+-----+
|United Kingdom |70       |     |
+---------------+---------+-----+
|China          |52       |     |
+---------------+---------+-----+

---

但它抛出了一个错误：字段列表中的未知列“count”

我首先得到前5个国家，例如：

SELECT vwr_cntry, COUNT(vwr_id) AS 'counts'
FROM viewer_log
GROUP BY vwr_cntry
ORDER BY COUNT(vwr_id) DESC LIMIT 5;

然后，将其包装到另一个查询中以计算总和，例如：

SELECT a.vwr_cntry, a.counts, SUM(a.counts) as 'sums'
FROM (
  SELECT vwr_cntry, COUNT(vwr_id) AS 'counts'
  FROM viewer_log
  GROUP BY vwr_cntry
  ORDER BY COUNT(vwr_id) DESC LIMIT 5
) a;

然后，添加计算百分比的公式，例如：

SELECT b.vwr_cntry, b.counts, b.sums, (b.counts/b.sums)*100 AS 'percentage'
FROM (
  SELECT a.vwr_cntry, a.counts, SUM(a.counts) as 'sums'
  FROM (
    SELECT vwr_cntry, COUNT(vwr_id) AS 'counts'
    FROM viewer_log
    GROUP BY vwr_cntry
    ORDER BY COUNT(vwr_id) DESC LIMIT 5
  ) a
) b;

---

像这样的方法应该会奏效：

SELECT
    vwr_cntry,
    COUNT(*) AS cntry_cnt,
    100.0 * COUNT(*) / (SELECT COUNT(*) FROM viewer_log) AS pct
FROM viewer_log
GROUP BY vwr_cntry
ORDER BY COUNT(*) DESC
LIMIT 5

---

这只是一个简单的

分组查询。它使用一个非相关子查询来查找总行数，用于计算百分比。
请参见第二部分vwr\u cntry的“您是否错过了一个组？”谢谢您的建议，但它仍然有错误。我认为这不能指“count1”谢谢，但根据人工计算，泰国游客的百分比应该是57%。但是从你的脚本来看只有0.01。它汇总了所有的行，而不仅仅是来自cntry的行_cnt@Wilf对不起，我忘了乘以100。