mysql - 没有子查询的过滤计数和总计数

Question

假设我有一个这样的表：

ID     Result
-------------
 1  ,  'pass'
 2  ,  'pass'
 3  ,  'fail'
 4  ,  'fail'
 5  ,  'fail'
 6 ,   'fail'

有什么简单的方法可以找到COUNT WHERE result = 'fail' AND total COUNT。

预期输出：

FailCount    TotalCount
-----------------------
    4            6

是的，我们可以使用这样的子查询来做到这一点：

SELECT 
(SELECT COUNT(result) FROM t WHERE result='fail') AS FAILCount
, COUNT(result)
AS TotalCount FROM t;

但是有没有办法这样做：

SELECT COUNT(WHERE Result='fail') , COUNT(Result) FROM ...

score 20 · Accepted Answer

ANSI SQL

SELECT 
   SUM(CASE WHEN Result='fail' THEN 1 ELSE 0 END) , 
   COUNT(*) FROM ...

MySQL 特定（如 eggyal 所指）

SELECT 
       SUM(Result='fail') , 
       COUNT(*) FROM ...

score 4 · Accepted Answer

是的，我们也可以这样使用：

SELECT 
   COUNT(CASE WHEN Result='fail' THEN 1 ELSE NULL END) , 
   COUNT(*) FROM ...

score 0 · Accepted Answer

SELECT 
   SUM(CASE WHEN Result='fail' THEN 1 ELSE 0 END) as FailCount, 
   COUNT(Result) as TotalCount FROM table_name

3 回答 3