Working days from a given date - sql

Question

User will select a date in frontend and flexibledays, say for example if they have selected '2014-07-17' as date and flexibledays as 2, then we need to display both 2 previous and next 2 working days as like below,
2014-07-15
2014-07-16
2014-07-17
2014-07-20
2014-07-21
excluding weekends (friday and saturday), for use weekends is friday and saturday.
I have used the below query
DECLARE #MinDate DATE, #MaxDate DATE;
SELECT #MinDate = DATEADD(Day, -#inyDays ,#dtDate), #MaxDate = DATEADD(Day,#inyDays ,#dtDate)
DECLARE #DayExclusionValue VARCHAR(20)
SELECT #DayExclusionValue = dbo.UDF_GetConfigSettingValue('DaysToExclude')
DECLARE #NumOfWeekends INT
SELECT #NumOfWeekends= (DATEDIFF(wk, #MinDate, #MaxDate) * 2) +(CASE WHEN DATENAME(dw, #MinDate) = 'Friday' THEN 1 ELSE 0 END) +(CASE WHEN DATENAME(dw, #MaxDate) = 'Saturday' THEN 1 ELSE 0 END)
SET #MaxDate = DATEADD(Day,#inyDays + #NumOfWeekends ,#dtDate)
;WITH CalculatedDates AS
(
SELECT dates = #MinDate
UNION ALL
SELECT DATEADD(day, 1, dates)
FROM CalculatedDates
WHERE DATEADD(day, 1, dates) <= #MaxDate
)
SELECT dates FROM CalculatedDates
WHERE dates >= CAST(GETDATE() AS DATE)
AND DATENAME(DW, dates) NOT IN (SELECT Value FROM UDF_GetTableFromString(#DayExclusionValue))
OPTION (MAXRECURSION 0);
but the above query is not working properly.
Can you pls suggest me any other solution.

Answer 1

This example will work for Oracle, you did not say what DB you were using. If you have a list of vacations you need to join that in as indicated. It would need to be a outerjoin, and you need to add a case or something so that the vacation tables 'exclude' days override the generated days.
Also I chose a multiplier on random. When only dealing with weekend 8 was more than enough, but if your vacation table includes a lot of consecutive vacation days it might no longer be.
select d from(
select rownum nn, d, sysdate - d, first_value (rownum) over (order by abs(sysdate-d)) zero_valu
from (
select sysdate+n d, to_char(sysdate+n,'DAY'), CASE to_char(sysdate+n,'D') WHEN '6' THEN 'exclude' WHEN '7' THEN 'exclude' ELSE 'include' END e_or_i from
(SELECT ROWNUM-9 n -- 9=flexibleday*8/2 +1
FROM ( SELECT 1 just_a_column
FROM dual
CONNECT BY LEVEL <= 16 -- 8=flexibleday * 8
)
)
) where e_or_i = 'include' -- in this step you need to join in a table of holidays or such if you need that.
) where abs(nn-7) <= 2 -- 2=flexiday
order by d

Answer 2

DECLARE #StartDate DATE = '2014-07-17';
SELECT *
FROM
(
--Show Closest Previous 2 Days Not In Friday or Saturday
SELECT TOP 2
DATEADD(DAY, -nr, #StartDate) CheckDate,
DATENAME(DW, DATEADD(DAY, -nr, #StartDate)) CheckName,
-nr CheckCount
FROM (VALUES(1),(2),(3),(4)) AS Numbers(nr)
WHERE DATENAME(DW, DATEADD(DAY, -nr, #StartDate)) NOT IN ('Friday','Saturday')
UNION ALL
--Show Todays Date If Not Friday or Saturday
SELECT TOP 1
DATEADD(DAY, +nr, #StartDate) CheckDate,
DATENAME(DW, DATEADD(DAY, +nr, #StartDate)) CheckName,
nr CheckCount
FROM (VALUES(0)) AS Numbers(nr)
WHERE DATENAME(DW, DATEADD(DAY, +nr, #StartDate)) NOT IN ('Friday','Saturday')
UNION ALL
--Show Closest Next 2 Days Not In Friday or Saturday
SELECT TOP 2
DATEADD(DAY, +nr, #StartDate) CheckDate,
DATENAME(DW, DATEADD(DAY, +nr, #StartDate)) CheckName,
nr CheckCount
FROM (VALUES(1),(2),(3),(4)) AS Numbers(nr)
WHERE DATENAME(DW, DATEADD(DAY, +nr, #StartDate)) NOT IN ('Friday','Saturday')
) d
ORDER BY d.CheckDate
I break it into 3 parts, previous 2 days, today (if applicable) and next 2 days
Here is the output:
CheckDate CheckName CheckCount
2014-07-15 Tuesday -2
2014-07-16 Wednesday -1
2014-07-17 Thursday 0
2014-07-20 Sunday 3
2014-07-21 Monday 4
I use the datename since not sure what ##datefirst your server is set to. the values() section is just a numbers table (you should create a numbers table as big as the amount of records you want to return plus any weekends you are crossing over) and then the TOP 2 in the first and last sections would be replaced with the number of days you wanted to return before and after.
**** Update with generic numbers table functionality added:
Here we declare the starting date and the number of previous and next days we would like to pull:
DECLARE #StartDate DATE = '2014-07-20';
DECLARE #MaxBusDays INT = 5
This next section creates a numbers table (can be easily found via google)
DECLARE #number_of_numbers INT = 100000;
;WITH
a AS (SELECT 1 AS i UNION ALL SELECT 1),
b AS (SELECT 1 AS i FROM a AS x, a AS y),
c AS (SELECT 1 AS i FROM b AS x, b AS y),
d AS (SELECT 1 AS i FROM c AS x, c AS y),
e AS (SELECT 1 AS i FROM d AS x, d AS y),
f AS (SELECT 1 AS i FROM e AS x, e AS y),
numbers AS
(
SELECT TOP(#number_of_numbers)
ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS number
FROM f
)
Now we use the numbers table and a row_number setting to pull only the number of rows before and after (plus the date of, if it's not fri/sat as wanted) that are working days (not fri/sat)
SELECT *
FROM
(
--Show Closest Previous x Working Days (Not Friday or Saturday)
SELECT * FROM
(
SELECT
DATEADD(DAY, -number, #StartDate) CheckDate,
DATENAME(DW, DATEADD(DAY, -number, #StartDate)) CheckName,
-number CheckCount,
ROW_NUMBER() OVER (ORDER BY number ASC) AS RowCounter
FROM Numbers
WHERE DATENAME(DW, DATEADD(DAY, -number, #StartDate)) NOT IN ('Friday','Saturday')
) a
WHERE a.RowCounter <= #MaxBusDays
UNION ALL
--Show Todays Date If Working Day (Not Friday or Saturday)
SELECT TOP 1
#StartDate CheckDate,
DATENAME(DW, #StartDate) CheckName,
0 CheckCount,
0 RowCounter
WHERE DATENAME(DW, #StartDate) NOT IN ('Friday','Saturday')
UNION ALL
--Show Closest Next x Working Days (Not Friday or Saturday)
SELECT * FROM
(
SELECT
DATEADD(DAY, +number, #StartDate) CheckDate,
DATENAME(DW, DATEADD(DAY, +number, #StartDate)) CheckName,
number CheckCount,
ROW_NUMBER() OVER (ORDER BY number ASC) AS RowCounter
FROM Numbers
WHERE DATENAME(DW, DATEADD(DAY, +number, #StartDate)) NOT IN ('Friday','Saturday')
) b
WHERE b.RowCounter <= #MaxBusDays
) c
ORDER BY c.CheckDate
Here is the output: (2014-07-20 is the middle row)
CheckDate CheckName CheckCount RowCounter
2014-07-13 Sunday -7 5
2014-07-14 Monday -6 4
2014-07-15 Tuesday -5 3
2014-07-16 Wednesday -4 2
2014-07-17 Thursday -3 1
2014-07-20 Sunday 0 0
2014-07-21 Monday 1 1
2014-07-22 Tuesday 2 2
2014-07-23 Wednesday 3 3
2014-07-24 Thursday 4 4
2014-07-27 Sunday 7 5