Oracle SQL分组集返回多行

Question

我正在开发一个Oracle sql脚本，与所有其他部门位置（location_id = 1700）相比，显示一个部门位置（location_id <> 1700）的平均值 - 它正在比较两个值，我期待只返回两行。我能够找到一个这样的查询：

select d.LOCATION_ID, round(avg(e.salary),2) AS "AVG SALARY", count(d.LOCATION_ID) from departments d
join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID
where d.location_id = 1700
group by grouping sets(d.LOCATION_ID);

这样我就会返回一行：

我的第二个查询返回四行而不是一行（就像我想的那样）：

select round(avg(e.salary),2) AS "AVG SALARY", count(d.LOCATION_ID) from departments d
join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID
where d.location_id <> 1700
group by grouping sets(d.LOCATION_ID);

这会返回4行，但我希望它只返回1：

我的希望是找出两个查询，然后将它们组合在一起 - 显然我需要在将它们放在一起之前克服第二个查询的障碍。
有什么想法吗？

Answer 1

尝试完全删除组别。听起来你只想要其中location_id = 1700和location_id＆lt;＆gt;的平均值。 1700然后UNION两个结果。

select '1700' as "LOCATION", round(avg(e.salary),2) AS "AVG SALARY", count(d.LOCATION_ID) as "COUNT"
from departments d
join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID
where d.location_id = 1700

union

select '<>1700' as "LOCATION", round(avg(e.salary),2) AS "AVG SALARY", count(d.LOCATION_ID) as "COUNT"
from departments d
join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID
where d.location_id <> 1700

Answer 2

select应包含在union all中，用于第二个查询。现在，您可以使用select d.location_id, round(avg(e.salary),2) AS "AVG SALARY", count(d.LOCATION_ID) from departments d join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID where d.location_id <> 1700 group by d.location_id 来组合结果集。

select
avg(case when d.location_id = 1700 then e.salary else 0 end) 
AS "AVG SALARY for location 1700", 
avg(case when d.location_id <> 1700 then e.salary else 0 end) 
AS "AVG SALARY for locations other than 1700"
from departments d
join employees e on e.DEPARTMENT_ID = d.DEPARTMENT_ID

然而，这可以使用条件聚合作为

在一个查询中表达

{{1}}

Answer 3

您可以考虑使用case代替locationid：

select (case when d.lcoation_id = 1700 then 1700 else -1 end) as LocationId,
       round(avg(e.salary), 2) AS "AVG SALARY",
       count(d.LOCATION_ID)
from departments d join
     employees e
     on e.DEPARTMENT_ID = d.DEPARTMENT_ID
group by grouping sets((case when d.lcoation_id = 1700 then 1700 else -1 end));

我不确定您是否需要grouping sets。如果你只想要两行，那么这可能就是你想要的：

select (case when d.lcoation_id = 1700 then 1700 else -1 end) as LocationId,
       round(avg(e.salary), 2) AS "AVG SALARY",
       count(d.LOCATION_ID)
from departments d join
     employees e
     on e.DEPARTMENT_ID = d.DEPARTMENT_ID
group by (case when d.lcoation_id = 1700 then 1700 else -1 end);