SQL Start Date and End Date Matching - sql

Question

I have one table that contains customer id and start date and one table that contains customer id and end date.
table A
customer_id
start_date
1
2022-01-01
1
2022-04-01
1
2022-07-01
2
2022-01-15
2
2022-03-25
3
2022-04-01
3
2022-08-01
4
2022-09-01
table B
customer_id
end_date
1
2022-01-25
1
2022-05-03
2
2022-03-24
2
2022-03-29
3
2022-04-15
Is there a way that I can get an output that looks like below?
desired output
customer_id
start_date
end_date
1
2022-01-01
2022-01-25
1
2022-04-01
2022-05-03
1
2022-07-01
2
2022-01-15
2022-03-24
2
2022-03-25
2022-03-29
3
2022-04-01
2022-04-15
3
2022-08-01
4
2022-09-01

Answer 1

As per your desire result please check the below query you can change it as per your table name and requirements.
DECLARE #table1 TABLE(
[customer_id] INT,
[start_date] DATE
)
DECLARE #table2 TABLE(
[customer_id] INT,
[end_date] DATE
)
INSERT INTO #table1 VALUES
(1,'2022-01-01'),
(1,'2022-04-01'),
(1,'2022-07-01'),
(2,'2022-01-15'),
(2,'2022-03-25'),
(3,'2022-04-01'),
(3,'2022-08-01'),
(4,'2022-09-01')
INSERT INTO #table2 VALUES
(1,'2022-01-25'),
(1,'2022-05-03'),
(2,'2022-03-24'),
(2,'2022-03-29'),
(3,'2022-04-15')
SELECT [Table1].[customer_id],[Table1].[start_date],[Table2].[end_date] FROM (
SELECT *, ROW_NUMBER() OVER (ORDER BY [start_date]) row_num FROM #table1
) AS [Table1]
LEFT JOIN (
SELECT t2.*, ROW_NUMBER() OVER (ORDER BY [end_date] ) row_num FROM #table2 t2
) AS [Table2]
ON [Table2].[customer_id] = [Table1].[customer_id]
AND [Table1].[row_num] = [Table2].[row_num]
ORDER BY [Table1].[customer_id]
Output

Answer 2

This hint is using TSQL in SQL Server.
select A.customer_id, A.start_date, B.end_date
from
(select X.costumer_id, X.start_date, ROW_NUMBER() over (order by X.start_date) as ORDEM from TableA X) A
left outer join (select X.customer_id, X.end_date, ROW_NUMBER() over (order by X.end_date ) as ORDEM from TableB X) B on A.customer_id = B.customer_id and A.ORDEM = B.ORDEM
order by A.customer_id, A.start_date
Hope it helps.

Answer 3

Here is how it's done in Vertica 12 - now that we have INTERPOLATE NEXT VALUE for the event series join :
\pset null (null)
WITH
tba(customer_id,start_date) AS (
SELECT 1,DATE '2022-01-01'
UNION ALL SELECT 1,DATE '2022-04-01'
UNION ALL SELECT 1,DATE '2022-07-01'
UNION ALL SELECT 2,DATE '2022-01-15'
UNION ALL SELECT 2,DATE '2022-03-25'
UNION ALL SELECT 3,DATE '2022-04-01'
UNION ALL SELECT 3,DATE '2022-08-01'
UNION ALL SELECT 4,DATE '2022-09-01'
)
,
tbb(customer_id,end_date) AS (
SELECT 1,DATE '2022-01-25'
UNION ALL SELECT 1,DATE '2022-05-03'
UNION ALL SELECT 2,DATE '2022-03-24'
UNION ALL SELECT 2,DATE '2022-03-29'
UNION ALL SELECT 3,DATE '2022-04-15'
)
SELECT
tba.customer_id
, start_date
, end_date
FROM tba
LEFT JOIN tbb
ON tba.customer_id = tbb.customer_id
AND end_date INTERPOLATE NEXT VALUE start_date
ORDER BY 1,2
;
-- out Null display is "(null)".
-- out customer_id | start_date | end_date
-- out -------------+------------+------------
-- out 1 | 2022-01-01 | 2022-01-25
-- out 1 | 2022-04-01 | 2022-05-03
-- out 1 | 2022-07-01 | (null)
-- out 2 | 2022-01-15 | 2022-03-24
-- out 2 | 2022-03-25 | 2022-03-29
-- out 3 | 2022-04-01 | 2022-04-15
-- out 3 | 2022-08-01 | (null)
-- out 4 | 2022-09-01 | (null)