问题描述
我有两张桌子:
第一个表:PATIENT
列:
ID number(PK),LastName varchar2,FirstName varchar2
和样本数据:
ID LastName FirstName
-------------------------
1 Jobs Tom
2 norks Jack
3 Loonie Peter
第二个表:PAYMENTS
带列:
ID number(PK),PATIENT_ID number (FK Patient.ID),PRICE number,EXTRA_PAYMENT number (takes only 0 or -1)
和样本数据:
ID PATIENT_ID PRICE EXTRA_PAYMENT
----------------------------------------
1 1 50€ 0
2 1 20€ 0
3 3 40€ 0
4 1 30€ 0
5 2 70€ 0
6 3 25€ 0
7 2 5€ -1
8 3 25€ 0
9 2 10€ -1
10 2 50€ 0
PATIENT PRICE EXTRA_PRICE
--------------------------------------------
Tom Jobs 100€ 0€
Jack norks 120€ 15€
Peter Loonie 90€ 0€
我该怎么做?
解决方法
加入表后可以使用聚合:
select p.firstname || ' ' || p.lastname as patient,sum(pm.price * pm.extra_price) as price,sum(pm.price * (1 - pm.extra_price)) as extra
from patients p left join
payments pm
on p.id = pm.patient_id
group by p.id,p.firstname || ' ' || p.lastname;
编辑:
对于已更改的问题,您可以使用case
:
select p.firstname || ' ' || p.lastname as patient,sum(case when pm.extra_price = 0 then pm.price end) as price,sum(case when pm.extra_price = -1 then pm.price end) as extra
from patients p left join
payments pm
on p.id = pm.patient_id
group by p.id,p.firstname || ' ' || p.lastname;