如何查询每月第一天到最后一天的记录数

Question

I would like to get the count of every day records from my table. For example I have a table “Employee” with the following fields ID, EmpNo, DateHired. And I have the following records

ID  EmpNo       DateHired
1   000001      3/2/2013 12:00:00 AM
2   000002      3/14/2013 12:00:00 AM
3   000003      3/14/2013 12:00:00 AM
4   000004      3/21/2013 12:00:00 AM
5   000005      4/2/2013 12:00:00 AM
6   000006      4/3/2013 12:00:00 AM
7   000007      4/3/2013 12:00:00 AM
8   000008      4/3/2013 12:00:00 AM
9   000009      4/3/2013 12:00:00 AM
10  000010      4/4/2013 12:00:00 AM
11  000011      4/5/2013 12:00:00 AM
12  000012      5/1/2013 12:00:00 AM

And the current month is april, how can I get this value:

Count   Day
0   4/1/2013 12:00:00 AM
1   4/2/2013 12:00:00 AM
4   4/3/2013 12:00:00 AM
1   4/4/2013 12:00:00 AM
1   4/5/2013 12:00:00 AM
0   4/6/2013 12:00:00 AM
0   4/7/2013 12:00:00 AM
0   4/8/2013 12:00:00 AM
Up to
0   4/30/2013 12:00:00 AM

Answer 1

You need to create a calendar for the whole month of April in order to get the whole dates of the month. With the aid of using Common Table Expression , you can get what you want.

After creating a calendar, join it with table Employee using LEFT JOIN so dates will have no matches on table Employee will still be included on the result.

WITH April_Calendar
AS
(
  SELECT CAST('20130401' as datetime) AS [date]
  UNION ALL
  SELECT DATEADD(dd, 1, [date])
  FROM   April_Calendar
  WHERE  DATEADD(dd, 1, [date]) <= '20130430'
)
SELECT a.date, COUNT(b.DateHired) totalCount
FROM   April_Calendar a
       LEFT JOIN Employee b
          ON a.date = b.DateHired
GROUP  BY a.date
ORDER  BY a.date

• SQLFiddle Demo

Answer 2

Try

SELECT   COUNT(*) as 'Count', DateHired as 'Day'
FROM     Employee
WHERE    DateHired BEWTEEN %date1 AND %date2
GROUP BY DateHired

Untested, should work though.

Answer 3

This could be the query...

SELECT COUNT(ID) as Count, DateHired FROM Employee GROUP BY DateHired

Following can be helpful in the case...

http://www.sqlite.org/lang_datefunc.html

Hope it helps..