How to group data with conditions? - sql

Question

I'm trying to turn my current table using sql
customer.id sale_date
15 1/12/2017
15 2/12/2017
15 7/12/2017
12 6/09/2017
12 12/09/2017
16 8/14/2017
13 6/01/2017
13 7/01/2017
into something like this.
sale_date1 is the first order date.
sale_date2 is any order date one month after sale_date1.
sale_date3 is any order date five months after sale_date1.
customer.id sale_date1 sale_date2 sale_date3(at least 5 months after sale_date1)
15 1/12/2017 2/12/2017 7/12/2017
12 6/07/2017 NULL 12/09/2017
16 8/14/2017 NULL NULL
13 6/01/2017 7/01/2017 NULL

Answer 1

One option here would be to use correlated sub-queries to populate each of the three columns:
WITH cte AS (
SELECT [customer.id], MIN(sale_date) AS min_sale_date
FROM yourTable
GROUP BY [customer.id]
)
SELECT
[customer.id],
min_sale_date AS sale_date1,
(SELECT MIN(t2.sale_date) FROM yourTable t2
WHERE t1.[customer.id] = t2.[customer.id] AND
t2.sale_date >= DATEADD(month, 1, t1.min_sale_date) AND
t2.sale_date < DATEADD(month, 5, t1.min_sale_date)) AS sale_date2,
(SELECT MIN(t2.sale_date) FROM yourTable t2
WHERE t1.[customer.id] = t2.[customer.id] AND
t2.sale_date >= DATEADD(month, 5, t1.min_sale_date)) AS sale_date3
FROM cte t1
ORDER BY [customer.id];
Demo

Answer 2

Try below using row_number() and conditional aggregation
select customerid,max(case when seq=1 then sale_date end) as date1,
max(case when seq=2 then sale_date end) as date2,
max(case when seq=3 then sale_date end) as date3
from
(
select *, row_number() over(partition by customerid order by sale_date) as seq
from tablename
)X
group by customerid

Answer 3

I THINK THIS IS WHAT YOU WANT
SELECT A.customer.id, SALES1.sale_date , SALES2.sale_date ,SALES3.sale_date , SALES4.sale_date,SALES5.sale_date from
(SELECT distinct customer.id ,
From yourTable)A
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=1)SALES1
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=2)SALES2
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=3)SALES3
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=2)SALES2
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=4)SALES4
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=2)SALES2
A.customer.id = SALES1.customer.id
LEFT JOIN
(SELECT * from
(SELECT customer.id, sale_date
ROW_NUMBER() OVER(ORDER BY sale_date ASC)
AS R1,
name, recovery_model_desc
FROM yourTable)S1 where R1=5)SALES5
A.customer.id = SALES1.customer.id

Answer 4

try this:
with mindate as (
select id, min(sale_date) MinDate,
DATEADD(month, 1, min(sale_date)) MinDatePlus1Month,
DATEADD(month, 5, min(sale_date)) MinDatePlus2Month
from yourtable
group by id
)
select f1.id, f1.MinDate sale_date1, f2.sale_date sale_date2, f3.sale_date sale_date3
from mindate f1
left outer join yourtable f2 on f1.id=f2.id and f1.MinDatePlus1Month=f2.sale_date
left outer join yourtable f3 on f1.id=f3.id and f1.MinDatePlus2Month=f3.sale_date