Substract one day form end date

Question

   
Hi All,
I have requirement where I need subtract one day from end_date if the start date of next row is the same and leaving the last row_id as it is and only if the customer id is the same.
Any suggestions
Current Values:
customer_id row_id start_date  end_date 
100         1      2014-04-01    2014-05-01
100         2      2014-05-01    2014-06-01
100         3      2014-06-01    2014-07-01     
Desired values:
customer_id row_id start_date  end_date 
100         1      2014-04-01    2014-04-30
100         2      2014-05-01    2014-06-30
100         3      2014-06-01    2014-07-01     
-kccrga http://dbatrend.blogspot.com.au/

Answer 1

Hi,
Not sure if the row_id is hard coded or a function, so went with a function. Try this code, it should give you what you need.
DECLARE @Test TABLE(customer_id INT,start_date DATETIME,end_date DATETIME)
INSERT INTO @Test
SELECT 100,'2014-04-01','2014-05-01' UNION
SELECT 100,'2014-05-01','2014-06-01' UNION
SELECT 100,'2014-06-01','2014-07-01' UNION
SELECT 200,'2014-04-01','2014-05-01' UNION
SELECT 200,'2014-05-01','2014-06-01' UNION
SELECT 200,'2014-06-01','2014-07-01'
SELECT customer_id,
start_date,
ROW_NUMBER() OVER (ORDER BY customer_id,start_date) RowNo,
ROW_NUMBER() OVER (PARTITION BY customer_id ORDER BY start_date) rowByCust,
end_date,
ISNULL((SELECT TOP 1 DATEADD(DAY,-1,start_date) FROM @Test NextDate WHERE NextDate.customer_id=TestData.customer_id AND NextDate.start_date>TestData.start_date ORDER BY start_date ASC)),end_date) new_end_date
FROM @Test TestData
customer_id
      start_date
RowNo
rowByCust
end_date
new_end_date
100
2014-04-01
1
1
2014-05-01
2014-04-30
100
2014-05-01
2
2
2014-06-01
2014-05-31
100
2014-06-01
3
3
2014-07-01
2014-07-01
200
2014-04-01
4
1
2014-05-01
2014-04-30
200
2014-05-01
5
2
2014-06-01
2014-05-31
200
2014-06-01
6
3
2014-07-01
2014-07-01
Gavin Clayton Claytabase Ltd www.claytabase.co.uk