SQL Server交叉连接查询

Question

我有下一个SQL Server表：

 Machine | Result 
 -----------------
 M2      |  0
 M1      |  1
 M3      |  0
 M1      |  1
 M2      |  1
 M1      |  0
 M2      |  0
 M1      |  1
 M3      |  0
 M1      |  1
 M3      |  0

我需要得到这样的报告：

Machine | Count 0's | Count 1's
--------------------------------
M1      |  1        |  4
M2      |  2        |  1
M3      |  3        |  0 

我尝试了下一个没有成功的查询：

SELECT A, B
FROM 
(SELECT COUNT(*) as A 
FROM MY_TABLE 
WHERE Result = 0)
GROUP BY Machine) a 
CROSS JOIN
(SELECT COUNT(*) as B 
FROM MY_TABLE
WHERE Result = 1)
GROUP BY Machine) b

你能帮助我吗？提前谢谢！

Answer 1

您可以使用条件聚合执行此操作：

select machine,
       sum(case when result = 0 then 1 else 0 end) as num_0,
       sum(case when result = 1 then 1 else 0 end) as num_1
from my_table
group by machine;