Cannot SUM the value of a sales amount field - various criteria, sales rep id and date ranges

Question

I wonder if someone can help me with this SQL Server 2016 query.

I have two tables with following data

TblSalesRep

This is the table holding the history of the territories that the sales rep looked after and the date range that they looked after it.

TerritoryId	SalesRep	FromDate	ToDate
15	Anne	2020-01-01	2020-06-02
15	Dave	2020-06-03	2020-06-16
15	Anne	2020-06-17	2020-06-22
18	Anne	2020-06-23	2999-12-31

tblSales

This is the table that holds the sales made by territory

TerritoryId	TransactionId	TransactionDate	ProductCode	Amount
15	1	2020-04-15	Bags	50
15	1	2020-04-15	Bags	50
15	2	2020-06-02	Bag	25
15	3	2020-06-03	Shoes	60
15	4	2020-06-07	Shoes	10
15	5	2020-06-17	Bags	15
15	6	2020-06-18	Bags	25
15	7	2020-06-25	Coat	100
18	8	2020-06-27	Bags	20

I’m trying to produce a report that displays the SalesRep and the total sold between two dates for a given SalesRep.

For example, if I provided a SalesRep = ‘Anne’ and a date range of ‘1 Jun 2020’ to ‘30 Jun 2020’ I would expect a result back of :

SalesRep    Sum
Anne        185

This is because it should exclude any transactions made between 03 Jun 2020 and 16 Jun 2020 as the territory was looked after by Dave for a couple of weeks and he conducted that business between those dates.

I’ve tried using the SUM() function whilst joining to TblSalesRep but the figures are not what I’m expecting.

Answer 1

There are more compact ways to write this, but this illustrates a way to do it.

First select the territories and periods that Anne was looking after that territory.

Then pull all the sales where the transaction date falls in one of the periods when Anne was covering the territory where the sale was made.

Then sum up the sales.

WITH
 territory_periods AS (
SELECT SalesRep, TerritoryID, FromDate, ToDate
  FROM tblSalesRep 
 WHERE SalesRep = 'Anne'
)
,sales AS (
SELECT p.SalesRep, s.Amount
  FROM tblSales s
  JOIN territory_periods p
    ON s.TerritoryID = p.TerritoryID 
   AND s.TransactionDate BETWEEN p.FromDate AND p.ToDate
)
SELECT SalesRep, Sum(Amount)
  FROM sales 
GROUP
    BY SalesRep
;

Answer 2

To answer your question, I did the following (see the fiddle here):

Create and populate tables - you could do this yourself for future questions - it's really helpful, removes duplication of effort and also eliminates copy and paste errors.

I've slightly changed the table definitions more or less in line with the SQL Style Guide - this is my personal preference - my advice is to pick a style and stick to it!

CREATE TABLE sales
(
  territory_id INT NOT NULL,
  transaction_id INT NOT NULL,
  transaction_date DATE NOT NULL,
  product_code VARCHAR (25) NOT NULL,
  amount INT NOT NULL
);

and

CREATE TABLE sales_rep
(
  territory_id INT NOT NULL,
  the_rep VARCHAR (10) NOT NULL,
  from_date DATE NOT NULL,
  to_date   DATE NOT NULL
);

data:

INSERT INTO sales VALUES
(15,           1,              '2020-04-15',      'Bags',            50),
(15,           1,              '2020-04-15',      'Bags',            50),
(15,           2,              '2020-06-02',      'Bags',             25),
(15,           3,              '2020-06-03',      'Shoes',           60),
(15,           4,              '2020-06-07',      'Shoes',           10),
(15,           5,              '2020-06-17',      'Bags',            15),
(15,           6,              '2020-06-18',      'Bags',            25),
(15,           7,              '2020-06-25',      'Coat',            100),
(18,           8,              '2020-06-27',      'Bags',            20);

and:

INSERT INTO sales_rep VALUES
(15,          'Anne',        '2020-01-01',  '2020-06-02'),
(15,          'Dave',        '2020-06-03',  '2020-06-16'),
(15,          'Anne' ,       '2020-06-17',  '2020-06-22'),
(18,          'Anne',        '2020-06-23',  '2999-12-31');

Then I ran the following query:

SELECT 
  sr.the_rep AS "Rep name", SUM(s.amount) AS "Total sales"
FROM sales s
JOIN sales_rep sr
  ON  s.transaction_date >= sr.from_date
  AND s.transaction_date <= sr.to_date
WHERE s.transaction_date >= '2020-06-01' AND s.transaction_date <= '2020-06-02'
OR    s.transaction_date >= '2020-06-17' AND s.transaction_date <= '2020-06-30'
GROUP BY sr.the_rep;

Result:

Rep name    Total sales
    Anne            185

I then used SET SHOWPLAN_TEXT ON (see the fiddle) to look at the two proposed (this one and @StephenK's) answers' performance - there is a slight difference in the plans, but I'm not a SQL Server man so I don't know which might be better. In any case, the tables are so small that the optimiser may or may not be using indexes that it might use with a large dataset!

I've run the SQL on different versions using the fiddle and the plans for the different queries remain the same!

I would urge you to test both solutions with a realistic dataset and go from there - reporting back here would be good!