SQL Server - Calculating target vs actual values per week for sales overview - sql

Question

I am new to SQL. I am trying to create an over view using these 2 tables
Actual sale
Week_Year
Unit 34_2020 35_2020 36_2020 37_2020
Unit 1 10 12 15 19
Unit 2 10 12 15 19
Unit 3 10 12 15 19
Target sale
Unit Total to be sold Start Date End Date
Unit 1 50 24-08-20 24-09-20
Unit 2 1000 18-01-20 01-01-21
Unit 3 1000 05-02-20 01-10-20
To combine into this resulting view with Targets and Actuals:
Unit 1 Unit 2 Unit 3
Week Target Actual Week Target Actual Week Target Actual
34_2020 11 10 3_2020 20 10 6_2020 20 10
35_2020 24 12 4_2020 40 12 7_2020 40 12
36_2020 36 15 5_2020 60 15 8_2020 60 15
37_2020 50 19 6_2020 80 19 9_2020 80 19
. 100 . . 100 .
36_2020 120 95 36_2020 700 650
37_2020 140 100 37_2020 800 700
. . 38_2020 .
. . 39_2020 .
. . 40_2020 1000
1_2021 1000
where column Target is 'Total to be sold' spread linearly between the available weeks.
How can I achieve this using SQL Server? Any inputs much appreciated. Thanks.

Answer 1

In order to make the week numbers (34, 35, 36, 37) correspond to system weeks the variable #start_wk_no sets the starting point. The actual sales needs to be unpivoted to join with projected sales. The query uses a tally (or numbers) function to generate the rows.
Data
drop table if exists dbo.test_actuals;
go
create table dbo.test_actuals(
Unit varchar(100) not null,
[34_2020] int not null,
[35_2020] int not null,
[36_2020] int not null,
[37_2020] int not null);
--select * from dbo.test_actuals
insert dbo.test_actuals values
('Unit 1', 10, 12, 15, 19),
('Unit 2', 10, 12, 15, 19),
('Unit 3', 10, 12, 15, 19);
drop table if exists dbo.test_target;
go
create table dbo.test_target(
Unit varchar(100) not null,
TotalToSell int not null,
StartDate date not null,
EndDate date not null)
insert dbo.test_target values
('Unit 1', 50, '08-24-2020', '09-24-2020'),
('Unit 2', 1000, '01-18-2020', '01-01-2021'),
('Unit 3', 1000, '02-05-2020', '10-01-20');
Query
/* based on system weeks, what is the start point */
declare
#start_wk_no int=6250;
;with unpvt_actuals_cte as (
select a.Unit, v.*
from
dbo.test_actuals a
cross apply
(values (34, [34_2020]), (35, [35_2020]), (36, [36_2020]), (36, [36_2020]), (37, [37_2020])) v([Week], act_sales))
select
t.Unit,
wd.wk_proj [Week],
isnull(act.act_sales, 0) [Actual],
TotalToSell/(wk_diff.wk_diff*1.0) [Target],
sum(TotalToSell/(wk_diff.wk_diff*1.0)) over (partition by t.Unit order by wd.wk_proj) Cum_Target
from
dbo.test_target t
cross apply
(select datediff(wk, t.StartDate, t.EndDate) wk_diff) wk_diff
cross apply
dbo.fnTally(0, wk_diff.wk_diff-1) f
cross apply
(select dateadd(wk, f.n, t.StartDate) wk_dt) wk
cross apply
(select datediff(week, 0, wk.wk_dt)-#start_wk_no wk_proj) wd
left join
unpvt_actuals_cte act on t.Unit=act.Unit
and wd.wk_proj=act.[Week];