How many equal days are between two date ranges, SQL

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 procedur

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