--关于递归累计求和
-->>TravyLee生成测试数据
if OBJECT_ID('test')is not null
drop table test
go
create table test(
id int identity(1,1),
deptid char(3),
empid char(4),
salary int
)
go
insert test(deptid,empid,salary)
select '101','1001',3500 union all
select '101','1002',2200 union all
select '102','1003',1900 union all
select '102','1004',5600 union all
select '102','1005',8000 union all
select '101','1006',2400 union all
select '101','1007',2300 union all
select '103','1008',3200 union all
select '103','1009',7800 union all
select '104','1010',4500 union all
select '101','1011',6500 union all
select '104','1012',3500 union all
select '104','1013',1900 union all
select '103','1014',2700 union all
select '102','1015',3100 union all
select '104','1016',2600
go
--problem 1：求出所有员工的工资的累计（从工资的最高到最低累计）
;with t
as(
select
px=ROW_NUMBER()over(order by salary desc),
deptid,empid,salary
from test
),
m as(
select px,deptid,empid,salary,salary as total
from t where px=1
union all
select
a.px,a.deptid,a.empid,a.salary,b.total+a.salary
from t a
join m b on a.px=b.px+1
)
select deptid,empid,salary,total from m
go
/*
deptid empid salary total
------------------------------
1 102 1005 8000 8000
2 103 1009 7800 15800
3 101 1011 6500 22300
4 102 1004 5600 27900
5 104 1010 4500 32400
6 101 1001 3500 35900
7 104 1012 3500 39400
8 103 1008 3200 42600
9 102 1015 3100 45700
10 103 1014 2700 48400
11 104 1016 2600 51000
12 101 1006 2400 53400
13 101 1007 2300 55700
14 101 1002 2200 57900
15 102 1003 1900 59800
16 104 1013 1900 61700
*/
--problem 2:分部门统计，并求出各部门在总工资中所占的百分比
;with t
as(
select
px=ROW_NUMBER()over(partition by deptid order by salary desc),
deptid,empid,salary
from test
),
m as(
select px,deptid,empid,salary,salary as total
from t where px=1
union all
select
a.px,a.deptid,a.empid,a.salary,b.total+a.salary
from t a
join m b on a.px=b.px+1 and a.deptid=b.deptid
)
select
deptid,empid,salary,total
from
m
order by
deptid,px
/*
deptid empid salary total
------------------------------
101 1011 6500 6500
101 1001 3500 10000
101 1006 2400 12400
101 1007 2300 14700
101 1002 2200 16900
102 1005 8000 8000
102 1004 5600 13600
102 1015 3100 16700
102 1003 1900 18600
103 1009 7800 7800
103 1008 3200 11000
103 1014 2700 13700
104 1010 4500 4500
104 1012 3500 8000
104 1016 2600 10600
104 1013 1900 12500
*/
