mysql - MY sql 查询查找#status

Question

我有一个包含列名课程和状态的表，如下所示

Course    Status
---------------------------
Math      Complete
Math      Complete
Math      Complete
Science   Incomplete
Science   Complete
Science   Complete

我想要一个给出以下结果的 MySQL 查询

Course    % Status_complete
--------------------------
Math        100%
Science     33.3%  

Answer 1

SELECT  Course,
        SUM(Status = 'Complete') / COUNT(*) * 1.0 AS STATUS_COMPLETE
FROM    TableName
GROUP   BY Course

• SQLFiddle 演示
• SQLFiddle 演示（带有 % 符号和 ROUND()）

Answer 2

用这个：-

SELECT  Course,
        SUM(Status = 'Complete') / COUNT(*) * 100.0 as PercentageComplete,
        SUM(Status = 'Incomplete') / COUNT(*) * 100.0 as PercentageIncomplete
FROM    CourseTable
GROUP   BY Course

输出 ：-

COURSE    PERCENTAGECOMPLETE    PERCENTAGEINCOMPLETE
Math             100                         0
Science        66.66667                  33.33333