SQL Case When Slowing Down Query - sql

Question

What I'm looking to do is quantify the total value of purchases and the number of months in which a purchase was made within three different timeframes by account. I only want to look at accounts who made a purchase between 1-1-2020 and 4-1-2021.
I'm wondering if there is a more streamlined way to pull in the fields I'm creating using CASE WHEN below (maybe through a series of queries to create the calculations and the left joining?). This query is taking extremely long to pull back, so I'd like to enhance this code where I can. All of my code and desired output is listed below. Thank you!
Creating a temporary table to pull account numbers:
DROP TABLE IF EXISTS #accounts
SELECT DISTINCT s.account_no, c.code, c.code_desc
INTO #accounts
FROM sales AS s
LEFT JOIN customer AS c ON s.account_no = c.account_no
WHERE s.tran_date BETWEEN '2020-01-01' AND '2021-04-01'
GROUP BY s.account_no, c.code, c.code_desc;
Confirming row counts:
SELECT COUNT (*)
FROM #accounts
ORDER BY account_no;
Creating Sales and Sales period count columns for three timeframes:
SELECT
s.account_no, c.code, c.code_desc
SUM(CASE
WHEN s.tran_date BETWEEN '2020-01-01' AND '2021-04-01'
THEN VALUE_USD
END) AS Total_Spend_Pre,
SUM(CASE
WHEN s.tran_date BETWEEN '2021-04-01' AND '2022-03-31'
THEN VALUE_USD
END) Total_Spend_During,
SUM(CASE
WHEN s.tran_date > '2022-04-01'
THEN VALUE_USD
END) Total_Spend_Post,
COUNT(DISTINCT CASE WHEN s.tran_date BETWEEN '2020-01-01' AND '2021-04-01' THEN CONCAT(s.bk_month, s.bk_year) END) Pre_Periods,
COUNT(DISTINCT CASE WHEN s.tran_date BETWEEN '2021-04-01' AND '2022-03-31' THEN CONCAT(s.bk_month, s.bk_year) END) During_Periods,
COUNT(DISTINCT CASE WHEN s.tran_date > '2022-04-01' THEN CONCAT(s.bk_month, s.bk_year) END) Post_Periods
FROM
sales AS s
LEFT JOIN
customer AS c ON s.account_no = c.account_no
WHERE
c.account_no IN (SELECT DISTINCT account_no
FROM #accounts)
GROUP BY
s.account_no, c.code, c.code_desc;
Desired output:
account_no
code
code_desc
Total_Spend_Pre
Total_Spend_During
Total_Spend_Post
Pre_Periods
During_Periods
Post_Periods
25
1234
OTHER
1000
2005
500
2
14
5
11
5678
PC
500
100
2220
5
11
2

Answer 1

You may use your date ranges to join with dataset, and 'Tag' your result like below, this will result in 3 rows, for each group. If you need them in a single row, have PIVOTE over it
;With DateRanges AS (
SELECT CAST('2020-01-01' AS DATE) StartDate, CAST('2021-04-01' AS DATE) EndDate, 'Pre' Tag UNION
SELECT '2021-04-01', '2022-03-31', 'During' UNION
SELECT '2022-04-01', Null, 'Post'
)
SELECT s.account_no, c.code, c.code_desc, d.Tag,
SUM(VALUE_USD) AS Total_Spend,
COUNT(DISTINCT CONCAT(s.bk_month, s.bk_year)) RecordCount
FROM sales as s
LEFT JOIN customer as c
INNER JOIN DateRanges D ON s.tran_date BETWEEN D.StartDate AND ISNULL(D.EndDate,s.tran_date)
ON s.account_no = c.account_no
WHERE c.account_no IN (SELECT DISTINCT account_no FROM #accounts)
GROUP BY s.account_no, c.code, c.code_desc;

Answer 2

with [cte_accountActivityPeriods] as (
select [PeriodOrdinal] = 1, [PeriodName] = 'Total Spend Pre', [PeriodStart] = convert(date,'2020-01-01',23) , [PeriodFinish] = convert(date,'2021-03-31',23) union
select [PeriodOrdinal] = 2, [PeriodName] = 'Total Spend During', [PeriodStart] = convert(date,'2021-04-01',23) , [PeriodFinish] = convert(date,'2022-03-31',23) union
select [PeriodOrdinal] = 3, [PeriodName] = 'Total Spend Post', [PeriodStart] = convert(date,'2022-04-01',23) , [PeriodFinish] = convert(date,'9999-12-31',23)
)
, [cte_allsalesForActivityPeriod]
SELECT s.account_no, bk_month, bk_year, [PeriodOrdinal], s.tran_date, s.value_usd
FROM sales as s
cross join [cte_accountActivityPeriods]
on s.[tran_date] between [cte_ActivityPeriods].[PeriodStart] and [cte_ActivityPeriods].[PeriodFinish]
)
, [cte_uniqueAccounts] as ( /*Unique and qualifying Accounts*/
select distinct account_no from [cte_allsalesForActivityPeriod]
inner join #accounts accs on accs.[account_no] = [cte_allsalesForActivityPeriod].[account_no]
)
, [cte_AllSalesAggregatedByPeriod] as (
select account_no, [PeriodOrdinal], bk_month, bk_year, [PeriodTotalSpend] = sum([value_usd])
from [cte_allsalesForActivityPeriod]
group by s.account_no, [PeriodOrdinal], bk_month, bk_year
)
, [cte_PeriodAnalysis] as (
select account_no, [PeriodOrdinal], [ActivePeriods] = count(distinct concat(bk_month, bk_year))
from [cte_AllSalesAggregatedByPeriod]
group by s.account_no, [PeriodOrdinal]
)
, [cte_pivot_clumsily] as (
/* Aggregations already done - so simple pivot */
select [cte_uniqueAccounts].[account_no]
, [Total_Spend_Pre] = case when [SaleVal].[PeriodOrdinal] in (1) then [SaleVal].[PeriodTotalSpend] else 0 end
, [Total_Spend_During] = case when [SaleVal].[PeriodOrdinal] in (2) then [SaleVal].[PeriodTotalSpend] else 0 end
, [Total_Spend_Post] = case when [SaleVal].[PeriodOrdinal] in (3) then [SaleVal].[PeriodTotalSpend] else 0 end
, [Pre_Periods] = case when [SalePrd].[PeriodOrdinal] in (1) then [SalePrd].[ActivePeriods] else 0 end
, [During_Periods] = case when [SalePrd].[PeriodOrdinal] in (2) then [SalePrd].[ActivePeriods] else 0 end
, [Post_Periods] = case when [SalePrd].[PeriodOrdinal] in (3) then [SalePrd].[ActivePeriods] else 0 end
from [cte_uniqueAccounts]
left join [cte_AllSalesAggregatedByPeriod] [SaleVal] on [SaleVal].[account_no] = [cte_uniqueAccounts].[account_no]
left join [cte_PeriodAnalysis] [SalePrd] on [SalePrd].[account_no] = [cte_uniqueAccounts].[account_no]
)
select c.code, c.code_desc, [cte_pivot_clumsily].*
from [cte_pivot_clumsily]
LEFT JOIN customer as c
ON [cte_pivot_clumsily].account_no = c.account_no