Question

我对SQL比较陌生。每个员工访问一个帐户进行技术测试，有时这是一个很好的尝试，有时候很糟糕，所以我需要计算大部分不良尝试的百分比，我的报告看起来应该是这样的：

选择员工，事件，总数，百分比来自my_table

employee |  event |  total |  percentage|
user1    |  good  |   50   |    50%     |
user1    |  bad   |   50   |    50%     |

Answer 1

尝试这样的计算每位员工的bad事件百分比

select employee,(sum(case when event = 'bad' then 1 else 0 end) / count(*)) * 100
From Yourtable
Group by employee

Answer 2

计算子查询中的总数，然后JOIN计算每行的百分比。

SELECT employee, event, COUNT(*),  COUNT(*) * 100.0 / t.total as percentage
FROM my_table
JOIN (SELECT employee, count(*) total
      FROM my_table
      GROUP BY employee) T
  ON my_table.employee = t.employee
GROUP BY employee, event

SQL从总计中获取不良记录的百分比

2 个答案: