How to build this sql query - sql

Question

i want to find the records in sql
from say 25-08-2012 to 01-09-2012
and i want to group by date
here is my query
SELECT CONVERT(VARCHAR(10), date, 105) AS dt,
COUNT(id) AS cnt
FROM tablename
WHERE date BETWEEN CONVERT(DATETIME, '21-08-2012 00:00:00:000',103)
AND CONVERT(DATETIME, '01-09-2012 23:59:00:000' ,103)
GROUP BY CONVERT(VARCHAR(10), date, 105)
i am getting result as
dt cnt
01-09-2012 48
27-08-2012 1
28-08-2012 3
29-08-2012 11
30-08-2012 3
but expect it as
dt cnt
25-08-2012 0
26-08-2012 0
01-09-2012 48
27-08-2012 1
28-08-2012 3
29-08-2012 11
30-08-2012 3
How i can modify above query
i also tried with CASE but no luck
Many Thanks..

Answer 1

The reason you are missing these dates in result is that there's no data for them in your table, however, the following would insure you are getting all of the dates in specified range:
CREATE TABLE #tmp_dates ([date] datetime)
DECLARE #dt_start datetime, #dt_end datetime, #dt_dif int
SET #dt_start = CONVERT(DATETIME, '21-08-2012 00:00:00:000',103)
SET #dt_end = CONVERT(DATETIME, '01-09-2012 23:59:00:000' ,103)
SET #dt_dif = datediff(day,#dt_start,#dt_end)
WHILE #dt_dif >= 0 BEGIN
INSERT INTO #tmp_dates
SELECT dateadd(day,#dt_dif,#dt_start)
SET #dt_dif = #dt_dif - 1
END
SELECT CONVERT(VARCHAR(10), t2.[date], 101) AS dt, COUNT(t1.id) AS cnt
INTO #tmp_result
FROM tablename t1
RIGHT OUTER JOIN #tmp_dates t2
ON CONVERT(VARCHAR(10), t1.[date], 101) = CONVERT(VARCHAR(10), t2.[date], 101)
GROUP BY CONVERT(VARCHAR(10), t2.[date], 101)
ORDER BY CONVERT(DATETIME,CONVERT(VARCHAR(10), t2.[date], 101)) ASC /* DESC */
SELECT convert(VARCHAR(10),CONVERT(DATETIME,dt),105) as dt,cnt FROM #tmp_result
DROP TABLE #tmp_dates
DROP TABLE #tmp_result

Answer 2

Your query cannot be directly modified to return the data you want. To count the dates in question, there must be records in the target table actually having those dates; in your case, however, the dates are merely parameters in the query. As a result, there is no way to incorporate them into your result set.
You must create a secondary table that includes all the dates for which you want data, and then recharacterize your query as a left outer join from that date table to your target table. This will, in turn, give you the zero counts for the dates present in the "date" table, but absent from the target table.

Answer 3

How about using IsNull()? Let me know if this works.
SELECT CONVERT(VARCHAR(10), date, 105) AS dt,
ISNULL(COUNT(id),0) AS cnt
FROM tablename
WHERE date BETWEEN CONVERT(DATETIME, '21-08-2012 00:00:00:000',103)
AND CONVERT(DATETIME, '01-09-2012 23:59:00:000' ,103)
GROUP BY CONVERT(VARCHAR(10), date, 105)