generate days from date range

Question

I would like to run a query like

select ... as days where `date` is between \'2010-01-20\' and \'2010-01-24\'

And return data like:

Answer 1

Generate dates between two date fields

If you are aware with SQL CTE query, then this solution will helps you to solve your question

Here is example

We have dates in one table

Table Name: “testdate”

STARTDATE   ENDDATE
10/24/2012  10/24/2012
10/27/2012  10/29/2012
10/30/2012  10/30/2012

Require Result:

STARTDATE
10/24/2012
10/27/2012
10/28/2012
10/29/2012
10/30/2012

Solution:

WITH CTE AS
  (SELECT DISTINCT convert(varchar(10),StartTime, 101) AS StartTime,
                   datediff(dd,StartTime, endTime) AS diff
   FROM dbo.testdate
   UNION ALL SELECT StartTime,
                    diff - 1 AS diff
   FROM CTE
   WHERE diff<> 0)
SELECT DISTINCT DateAdd(dd,diff, StartTime) AS StartTime
FROM CTE

Explanation: CTE Recursive query explanation

• First part of query:
  
  SELECT DISTINCT convert(varchar(10), StartTime, 101) AS StartTime, datediff(dd, StartTime, endTime) AS diff FROM dbo.testdate
  
  Explanation: firstcolumn is “startdate”, second column is difference of start and end date in days and it will be consider as “diff” column

• Second part of query:
  
  UNION ALL SELECT StartTime, diff-1 AS diff FROM CTE WHERE diff<>0
  
  Explanation: Union all will inherit result of above query until result goes null, So “StartTime” result is inherit from generated CTE query, and from diff, decrease - 1, so its looks like 3, 2, and 1 until 0

For example

STARTDATE   DIFF
10/24/2012  0
10/27/2012  0
10/27/2012  1
10/27/2012  2
10/30/2012  0

Result Specification

STARTDATE       Specification
10/24/2012  --> From Record 1
10/27/2012  --> From Record 2
10/27/2012  --> From Record 2
10/27/2012  --> From Record 2
10/30/2012  --> From Record 3

• 3rd Part of Query
  
  

  SELECT DISTINCT DateAdd(dd,diff, StartTime) AS StartTime FROM CTE
  
  It will add day “diff” in “startdate” so result should be as below

Result

STARTDATE
10/24/2012
10/27/2012
10/28/2012
10/29/2012
10/30/2012