Question

我有以下SQL表

系

|name|employees|

员工

|name|gender|type|dead |
|John|male  |good|yes  |
|Mary|female|bad |no   |
|Joe |male  |ugly|maybe|

我想写一个返回

的语句

| type | n of employees | n of male employees | n of departments |

我有

SELECT e.type, count(e), count(d) 
FROM Department d 
JOIN d.employees e
WHERE e.dead = maybe 
GROUP BY e.type

当然，那就是错过了“男性雇员”。我被困在这里，因为我不确定，在哪里指定附加条款e.gender = male。

我忘了提及：HQL或标准会很好。

Answer 1

假设您的原始查询和架构正确无误：

SELECT 
   e.type, 
   count(e), 
   count(d), 
   count (case when gender = 'male' then 1 else NULL end) AS NumberOfMaleEmployees
from Department d 
JOIN d.employees e
WHERE e.dead = 'maybe' 
GROUP BY e.type

Answer 2

仅供参考：

SELECT 
   e.type, 
   count(e), 
   count(d), 
   sum(case when gender = 'male' then 1 else 0 end)
from Department d 
JOIN d.employees e
WHERE e.dead = 'maybe' 
GROUP BY e.type

适用于HQL。谢谢大家！

SQL语句，子查询计数？

2 个答案: