Question

我正在尝试将这两个选择查询结合起来，但是count函数让我对Oracle感到困惑：

select person.first_name, COUNT(person.PERSON_ID) as Active
FROM incident, person
where person.PERSON_ID = incident.OWNER_ID
and incident.incident_id = 1
AND (incident.dept_id = 111 OR incident.dept_id = 222)
GROUP BY person.first_name;


select person.first_name, COUNT(person.PERSON_ID) as NonActive
FROM incident, person
where person.PERSON_ID = incident.OWNER_ID
AND incident.incident_id = 2
AND (incident.dept_id = 111OR incident.dept_id = 222)
GROUP BY person.first_name

我正在尝试将单个结果返回为：

FIRST_NAME ACTIVE NonActive
Bob          5       11
John         3       14

这样做的最佳（有效）方法是什么？

Answer 1

以下是两种方法。我很确定SUM CASE会更好但你可以自己测试

使用SUM CASE

select person.first_name, 
SUM(case when incident.incident_id =1 THEN 1 ELSE 0 END) as Active,
SUM(case when incident.incident_id =2 THEN 1 ELSE 0 END) AS NonActive,

FROM incident, person
where person.PERSON_ID = incident.OWNER_ID

   AND (incident.dept_id = 111 OR incident.dept_id = 222)
   AND incident.incident_id IN (1,2)

GROUP BY person.first_name;

使用JOIN

SELECT  DISTINCT
    p.First_name,
    Acive.Active,
    NonActive.NonActive
FROM
PERSON p

LEFT JOIN 
(
select person.first_name, COUNT(person.PERSON_ID) as Active
FROM incident, person
where person.PERSON_ID = incident.OWNER_ID
and incident.incident_id = 1
AND (incident.dept_id = 111 OR incident.dept_id = 222)
GROUP BY person.first_name;
) Active
ON p.first_name = active.first_name
LEFT JOIN 
(
select person.first_name, COUNT(person.PERSON_ID) as NonActive
FROM incident, person
where person.PERSON_ID = incident.OWNER_ID
AND incident.incident_id = 2
AND (incident.dept_id = 111OR incident.dept_id = 222)
GROUP BY person.first_name
) NonActive

ON p.first_name = NonActive.first_name

where Active.First_name is not null
and NonActive.First_name is not null

Answer 2

我相信你想要对incident_id而不是person_id进行计数;这样，您可以将两个查询合并为一个并获得所需的结果。

使用COUNT的多个Select语句

2 个答案: