因此，我们假设我有两个表，cars和engines。每辆车都有一个id列和sold_date列，指的是汽车售出的日期。每个引擎都有car_id和type列，其中第一列是cars表的外键，第二列是引擎的类型名称，可以是任何来自V1至V999。
所以我想得到的是8月1日到8月3日期间的日期列表，其中包括各种类型的引擎和许多销售过的汽车：
sold_date engine_type number_of_sold_cards
08.01.2015 V8 6
08.01.2015 V6 8
08.01.2015 V4 9
08.02.2015 V8 15
08.02.2015 V6 0
08.02.2015 V4 5
08.03.2015 V8 4
08.03.2015 V6 6
08.03.2015 V4 0
这个例子假设在这3天内只卖了带发动机的汽车＆＃39; V8，V6和V4的类型。这意味着如果在此期间（V8，V6，V4，V2，V0）已售出5种类型的发动机，我每个日期需要5行
答案 0 :(得分：1)
分区外连接到救援！
with cars as (select 1 id, to_date('01/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 2 id, to_date('01/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 3 id, to_date('02/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 4 id, to_date('03/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 5 id, to_date('01/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 6 id, to_date('01/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 7 id, to_date('03/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 8 id, to_date('03/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 9 id, to_date('02/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 10 id, to_date('02/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 11 id, to_date('02/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 12 id, to_date('04/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 13 id, to_date('04/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 14 id, to_date('04/08/2015', 'dd/mm/yyyy') sold_date from dual union all
select 14 id, to_date('04/08/2015', 'dd/mm/yyyy') sold_date from dual),
engines as (select 1 car_id, 'V8' engine_type from dual union all
select 2 car_id, 'V8' engine_type from dual union all
select 3 car_id, 'V8' engine_type from dual union all
select 4 car_id, 'V8' engine_type from dual union all
select 5 car_id, 'V4' engine_type from dual union all
select 6 car_id, 'V4' engine_type from dual union all
select 7 car_id, 'V4' engine_type from dual union all
select 8 car_id, 'V4' engine_type from dual union all
select 9 car_id, 'V6' engine_type from dual union all
select 10 car_id, 'V6' engine_type from dual union all
select 11 car_id, 'V6' engine_type from dual union all
select 12 car_id, 'V6' engine_type from dual union all
select 13 car_id, 'V2' engine_type from dual union all
select 14 car_id, 'V2' engine_type from dual union all
select 15 car_id, 'V0' engine_type from dual),
engine_types as (select distinct engine_type from engines),
res as (select c.id car_id,
e.engine_type,
c.sold_date
from engines e
inner join cars c on (e.car_id = c.id)),
final_res as (select et.engine_type,
res.sold_date
from engine_types et
left outer join res on (et.engine_type = res.engine_type)),
dates as (select to_date('01/08/2015', 'dd/mm/yyyy') - 1 + level dt -- paramaterise the start date
from dual
connect by level <= to_date('03/08/2015', 'dd/mm/yyyy') - to_date('01/08/2015', 'dd/mm/yyyy') + 1 -- paramaterise the start and end dates
)
select dts.dt,
fr.engine_type,
count(fr.sold_date) cnt
from dates dts
left outer join final_res fr partition by (fr.engine_type) on (dts.dt = fr.sold_date)
group by dts.dt,
fr.engine_type
order by dts.dt,
fr.engine_type;
DT ENGINE_TYPE CNT
---------- ----------- ----------
01/08/2015 V0 0
01/08/2015 V2 0
01/08/2015 V4 2
01/08/2015 V6 0
01/08/2015 V8 2
02/08/2015 V0 0
02/08/2015 V2 0
02/08/2015 V4 0
02/08/2015 V6 3
02/08/2015 V8 1
03/08/2015 V0 0
03/08/2015 V2 0
03/08/2015 V4 2
03/08/2015 V6 0
03/08/2015 V8 1
第一个和第二个子查询（“汽车”和“引擎”）只是模仿你的桌子;您不需要在查询中包含它们。
“engine_types”子查询只是获取引擎表中使用的不同engine_types列表。如果您有其他表列出了可用的engine_types，那么请改用它。
“dates”子查询只是生成给定日期范围之间的日期列表 - 在理想的世界中，开始日期和结束日期将被参数化（假设这是在PL / SQL或其他日期中运行）。 / p>
“res”子查询在汽车和引擎表上进行连接，以获得每个日期销售的引擎类型。
“final_res”子查询外部连接res和engine_types子查询，以便列出每个引擎类型以及sold_date（如果已售出）。
一旦你有了，那么就可以很容易地在final_res子查询上对日期子查询进行分区外连接。
答案 1 :(得分：0)
您需要加入汽车和引擎表。需要按sold_date和engine_type计算已售出的汽车和组：
select c.sold_date
,e.engine_type
,count(*) as number_of_sold_cars
from cars c
inner join engines e on c.id = e.car_id
where c.sold_date between date '2015-08-01' and date '2015-08-03'
group by c.sold_date,e.engine_type
更新
使用此查询，您将在所选时间段内销售所有引擎类型。如果在特定日期没有出售此引擎类型，则number_of_sold_cars将为0：
with engine_type as (
select distinct e.engine_type
from cars c
inner join engines e on c.id = e.car_id
where c.sold_date between date '2015-08-01' and date '2015-08-03'
)
select c.sold_date
,t.engine_type
,count(*) as number_of_sold_cars
from cars c
inner join engines e on c.id = e.car_id
left join enginte_type t on t.engine_type = e.engine_type
where c.sold_date between date '2015-08-01' and date '2015-08-03'
group by c.sold_date,t.engine_type