issue in a date range creation - sql-server

Question

I have been creating a date range, but in some cases a have a problem:
This is what I have: TABLE_1
date customer_id status total
---- ------------- -------- -------
20120201 1 a 10
20120202 1 a 20
20120203 1 b 20
20120204 1 b 20
20120205 1 a 20
20120206 1 a 20
20120201 2 d 30
20120202 2 e 40
After the execution of my procedure, I have this: TABLE_2
customer_id status start_date end_date
------------- -------- ----------- ---------
1 a 20120201 NULL
1 b 20120203 20120131
2 d 20120201 20120201
2 e 20120202 NULL
But this is what i want, a table with date ranges based on customer_id and status (end_date represents register with most recent date): TABLE_3
customer_id status start_date end_date
------------- -------- ----------- ---------
1 a 20120201 20120202
1 b 20120203 20120204
1 a 20120205 NULL
2 d 20120201 20120201
2 e 20120202 NULL
My store procedure look like this:
;WITH TEMP AS (
SELECT
Date
customer_id
status
FROM table_1
GROUP BY
date,
customer_id,
status
)
,TEMP2 AS (
SELECT
ID = ROW_NUMBER() OVER(PARTITION BY customer_id ORDER BY MAX(date) DESC),
start_date = MIN(date),
end_date = MAX(date),
[customer_id],
[status]
FROM TEMP
GROUP BY
[customer_id],
[status]
)
SELECT
A.customer_id,
A.status,
A.start_date,
end_date = DATEADD(DAY,-1,B.start_date)
FROM TEMP2 A
LEFT JOIN TEMP2 B
ON A.customer_id = B.customer_id
AND A.ID = B.ID + 1
I know my error is in the creation of CTE TEMP2, because this code can´t discriminate for a customer_id with a status with two occurrences in different ranges of time, based on the 'group by' sentence
I can´t figure out how to do that...

Answer 1

Try this. Hope it works now.
DECLARE #table_1 TABLE (
date DATETIME,
customer_id INT,
status CHAR(1),
total INT
)
INSERT #table_1 (date, customer_id, status, total)
VALUES
('20120201', 1, 'a', 10),
('20120202', 1, 'a', 20),
('20120203', 1, 'b', 20),
('20120204', 1, 'b', 20),
('20120205', 1, 'a', 20),
('20120206', 1, 'a', 20),
('20120201', 2, 'd', 30),
('20120202', 2, 'e', 40)
;WITH CTE_1 AS (
SELECT
customer_id,
status,
date,
ROW_NUMBER() OVER(PARTITION BY customer_id ORDER BY date ASC) AS seq
FROM #table_1
),
CTE_2 AS (
SELECT
customer_id,
status,
date,
seq,
1 AS flg,
1 AS seq2
FROM CTE_1
WHERE
seq = 1
UNION ALL
SELECT
CTE_1.customer_id,
CTE_1.status,
CTE_1.date,
CTE_1.seq,
CASE WHEN CTE_2.status = CTE_1.status THEN 0 ELSE 1 END,
CASE WHEN CTE_2.status = CTE_1.status THEN CTE_2.seq2 ELSE CTE_2.seq2 + 1 END
FROM CTE_1
INNER JOIN CTE_2
ON CTE_1.customer_id = CTE_2.customer_id
AND CTE_1.seq = CTE_2.seq + 1
)
SELECT
st.customer_id,
st.status,
st.date AS start_date,
DATEADD(DAY, -1, en.date) AS end_date
FROM CTE_2 AS st
LEFT JOIN CTE_2 AS en
ON st.customer_id = en.customer_id
AND st.seq2 = en.seq2 - 1
AND en.flg = 1
WHERE
st.flg = 1
ORDER BY
st.customer_id,
st.seq2