How many equal days are between two date ranges, SQL - mysql

Question

I have table with date ranges, like this:
DATE DATE2
14.03.2013 17.03.2013
13.04.2013 02.05.2013
I have to create a procedure, that returns day count that is equal to two date ranges, one which is in the table and another one.
Forexample, I have date range in the table like this 14.03.2013 - 17.03.2013 and another one, which is declared in procedure like this 02.03.2013 - 16.03.2013, so in this case day count would be 3, because, both date ranges have dates between 14.03.2013 and 16.03.2013.

Answer 1

suppose your table is called daterange and you have parameters defined #param1 and param2 in your procedure then something on these lines should work:
set #param1 := cast('2013-03-14' as date);
set #param2 := cast('2013-03-16' as date);
select
datediff(least(date2,#param2),#param1)+1
from daterange where #param1 between date1 and date2
See example in sqlfiddle

Answer 2

You should be able to adapt this T-SQL function to MySQL
IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[fu_RPT_OverlappingDateRangesDays]') AND type in (N'FN', N'IF', N'TF', N'FS', N'FT'))
DROP FUNCTION [dbo].[fu_RPT_OverlappingDateRangesDays]
GO
-- ======================================================================================================================
-- Author: Stefan Steiger
-- ALTER date: 11.06.2015
-- Alter date: 11.06.2015
-- Description: Calculate the number of overlapping days in two date-ranges
-- http://stackoverflow.com/questions/20836429/how-to-gets-the-number-of-overlapping-days-between-2-ranges
-- ======================================================================================================================
-- DECLARE #firstStart datetime
-- DECLARE #firstEnd datetime
-- DECLARE #secondStart datetime
-- DECLARE #secondEnd datetime
-- SET #firstStart = '01.01.2015'
-- SET #firstEnd = '31.01.2015'
-- SET #secondStart = '15.01.2014'
-- SET #secondEnd = '15.02.2015'
-- SELECT dbo.fu_RPT_OverlappingDateRangesDays( #firstStart, #firstEnd, #secondStart, #secondEnd )
CREATE FUNCTION [dbo].[fu_RPT_OverlappingDateRangesDays]
(
#firstStart datetime
,#firstEnd datetime
,#secondStart datetime
,#secondEnd datetime
)
RETURNS integer
AS
BEGIN
DECLARE #maxStart datetime
DECLARE #minEnd datetime
DECLARE #interval int
IF #firstStart IS NULL OR #firstEnd IS NULL OR #secondStart IS NULL OR #secondEnd IS NULL
-- RETURN 0
RETURN NULL
IF #firstEnd < #firstStart
RETURN 0
IF #secondEnd < #secondStart
RETURN 0
SET #maxStart = #secondStart
SET #minEnd = #secondEnd
IF #firstStart > #secondStart
SET #maxStart = #firstStart
IF #firstEnd < #secondEnd
SET #minEnd = #firstEnd
-- PRINT #maxStart
-- PRINT #minEnd
--SET #interval = DATEDIFF(DAY, #maxStart, #minEnd) + 1
SET #interval = {fn timestampdiff(SQL_TSI_DAY, #maxStart, #minEnd)} + 1
IF #interval < 0
SET #interval = 0
-- PRINT #interval
RETURN #interval
END
GO