asked on # Fix Code to Accept Negative Input for AddBusinessDays to date?

Hi Experts,

Can anyone tweak this code, below, to work with a negative date input to subtract business days from a given date?

Thanks,

Steve

Can anyone tweak this code, below, to work with a negative date input to subtract business days from a given date?

Thanks,

Steve

```
ALTER function [dbo].[DateAddWorkDay]
(@days int,@FromDate Date)
returns Date
as
begin
declare @result date
set @result = (
select b
from
(
SELECT
b,
(DATEDIFF(dd, a, b))
-(DATEDIFF(wk, a, b) * 2)
-(CASE WHEN DATENAME(dw, a) = 'Sunday' THEN 1 ELSE 0 END)
-(CASE WHEN DATENAME(dw, b) = 'Saturday' THEN 1 ELSE 0 END)
-COUNT(o.Holiday)
as workday
from
(
select
@FromDate as a,
dateadd(DAY,num +@days,@FromDate) as b
from (select row_number() over (order by (select NULL)) as num
from Information_Schema.columns
) t
where num <= 100
) dt
left join Holiday o on o.Holiday between a and b and DATENAME(dw, o.Holiday) not in('Saturday','Sunday')
where DATENAME(dw, b) not in('Saturday','Sunday')
and b not in (select Holiday from Holiday where Holiday between a and b)
group by a,b
) du
where workday =@days
)
return @result
end
```

DatabasesMicrosoft SQL ServerMicrosoft SQL Server 2008SQL

For negative @Days input, if I interpret your function correctly, you might need to change the code in 2 places:

1. Go back to the dates instead of checking forward

2. and the below WHERE condition in 2 places

where condition from

If possible, kindly provide the table structure of holidays table so that I can check it out once whether this will work fine or not..

1. Go back to the dates instead of checking forward

```
dateadd(DAY,-num +@days,@FromDate)
```

to```
dateadd(DAY,case when num > 0 then num +@days else -num+@days end,@FromDate)
```

2. and the below WHERE condition in 2 places

where condition from

```
o.Holiday between a and b
```

to ```
((@days > 0 AND o.Holiday BETWEEN a and b) OR (@days < 0 and o.Holiday between b and a))
```

to get the records fetched out..If possible, kindly provide the table structure of holidays table so that I can check it out once whether this will work fine or not..

Thanks guys for the input. I tried your suggestion, Raja, and I'm getting a null output in both + and - days cases.

Here's the Holiday table, below, with the code with your suggested edits.

Here's the Holiday table, below, with the code with your suggested edits.

```
ALTER function [dbo].[DateAddWorkDay]
(@days int,@FromDate Date)
returns Date
as
begin
declare @result date
set @result = (
select b
from
(
SELECT
b,
(DATEDIFF(dd, a, b))
-(DATEDIFF(wk, a, b) * 2)
-(CASE WHEN DATENAME(dw, a) = 'Sunday' THEN 1 ELSE 0 END)
-(CASE WHEN DATENAME(dw, b) = 'Saturday' THEN 1 ELSE 0 END)
-COUNT(o.Holiday)
as workday
from
(
select
@FromDate as a,
dateadd(DAY,case when num > 0 then num +@days else -num+@days end,@FromDate) as b
from (select row_number() over (order by (select NULL)) as num
from Information_Schema.columns
) t
where num <= 100
) dt
left join Holiday o on
((@days > 0 AND o.Holiday BETWEEN a and b) OR (@days < 0 and o.Holiday between b and a))
AND DATENAME(dw, o.Holiday) not in('Saturday','Sunday')
where DATENAME(dw, b) not in('Saturday','Sunday')
and b not in (select Holiday from Holiday where Holiday between a and b)
group by a,b
) du
where workday =@days
)
return @result
end
```

```
CREATE TABLE [dbo].[Holiday](
[Holiday] [date] NULL
) ON [PRIMARY]
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-01-01' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-01-01' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-09-03' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-11-22' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-11-23' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-12-25' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-12-26' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-12-27' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-12-28' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2018-12-31' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-01-01' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-05-27' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-07-04' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-09-02' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-11-28' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-11-29' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-12-25' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-12-26' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-12-27' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-12-30' AS Date))
GO
INSERT [dbo].[Holiday] ([Holiday]) VALUES (CAST(N'2019-12-31' AS Date))
GO
```

Experts Exchange has (a) saved my job multiple times, (b) saved me hours, days, and even weeks of work, and often (c) makes me look like a superhero! This place is MAGIC!

Walt Forbes

Log in or sign up to see answer

Become an EE member today7-DAY FREE TRIAL

Members can start a 7-Day Free trial then enjoy unlimited access to the platform

or

Learn why we charge membership fees

We get it - no one likes a content blocker. Take one extra minute and find out why we block content.

Not exactly the question you had in mind?

Sign up for an EE membership and get your own personalized solution. With an EE membership, you can ask unlimited troubleshooting, research, or opinion questions.

ask a question
Thanks very much,gentlemen, in particular Raja!

All the Best,

Steve

All the Best,

Steve

Welcome, Steve!!

you already have this:

Open in new window

it should worked if @days is negative too