我的SQL查询来查找＃状态

Question

我有包含列名课程和状态像下面

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

我想MySQL查询表谁给下面的结果

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 Demo
• SQLFiddle Demo (with % symbol and ROUND())

Answer 2

使用此： -

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