USE [Vertragsverwaltung_20160404]
GO
/****** Object:  UserDefinedFunction [dbo].[Get_Dateperiode]    Script Date: 02.12.2016 09:08:53 ******/
DROP FUNCTION [dbo].[Get_Dateperiode]
GO
/****** Object:  UserDefinedFunction [dbo].[Get_Dateperiode]    Script Date: 02.12.2016 09:08:55 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

-- =============================================
-- Author:		<Author,,Name>
-- Create date: <Create Date, ,>
-- Description:	<Description, ,>
-- =============================================
Create FUNCTION [dbo].[Get_Dateperiode] 
(
   @type varchar(255),
   @startperiode int
)
Returns datetime
AS
BEGIN
   declare @dt datetime
   declare @offset int
   if @type='ActWeek' begin
      if @startperiode=1 begin
         set @dt=DATEADD(wk, DATEDIFF(wk, 6, getdate()), 6)
         set @dt=dateadd(dd,1,@dt)
      end   
      if @startperiode=0 begin 
         set @dt=DATEADD(wk, DATEDIFF(wk, 5, getdate()), 5)
         set @dt=dateadd(dd,2,@dt)
         set @dt=dateadd(ms,-3,@dt)
      end   
      return @dt   
   end   
   if @type='ActMonth' begin
      if @startperiode=1 set @dt=DATEADD(mm, DATEDIFF(mm,0,getdate()), 0)
      if @startperiode=0 set @dt=Dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,getdate()  )+1, 0))
      return @dt
   end   
   if @type='ActQuarter' begin
      if @startperiode=1 set @dt= DATEADD(qq, DATEDIFF(qq,0,getdate()), 0)
      if @startperiode=0 begin
         set @dt= dateadd(qq,datediff(qq,-1,getdate()),-1)
         set @dt=dateadd(dd,1,@dt)
         set @dt=dateadd(ms,-3,@dt)
      end   
      return @dt
   end   
   if @type='ActYear' begin
      if @startperiode=1 set @dt = DATEADD(yy, DATEDIFF(yy,0,getdate()), 0)
      if @startperiode=0 set @dt = dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()  )+1, 0))
      return @dt
   end

   declare @calcdate datetime
   if @type='LastWeek' begin
      set @calcdate=dateadd(wk,-1,getdate())
      if @startperiode=1 begin
         set @dt=DATEADD(wk, DATEDIFF(wk, 6, @calcdate), 6)
         set @dt=dateadd(dd,1,@dt)
      end   
      if @startperiode=0 begin 
         set @dt=DATEADD(wk, DATEDIFF(wk, 5, @calcdate), 5)
         set @dt=dateadd(dd,2,@dt)
         set @dt=dateadd(ms,-3,@dt)
      end   
      return @dt   
   end   
   if @type='LastMonth' begin
      set @calcdate=dateadd(mm,-1,getdate())
      if @startperiode=1 set @dt=DATEADD(mm, DATEDIFF(mm,0,@calcdate), 0)
      if @startperiode=0 set @dt=Dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,@calcdate  )+1, 0))
      return @dt
   end   
   if @type='LastQuarter' begin
      set @calcdate=dateadd(qq,-1,getdate())
      if @startperiode=1 set @dt= DATEADD(qq, DATEDIFF(qq,0,@calcdate), 0)
      if @startperiode=0 begin
         set @dt= dateadd(qq,datediff(qq,-1,@calcdate),-1)
         set @dt=dateadd(dd,1,@dt)
         set @dt=dateadd(ms,-3,@dt)
      end   
      return @dt
   end   
   if @type='LastYear' begin
      set @calcdate=dateadd(yy,-1,getdate())
      if @startperiode=1 set @dt = DATEADD(yy, DATEDIFF(yy,0,@calcdate), 0)
      if @startperiode=0 set @dt = dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,@calcdate  )+1, 0))
      return @dt
   end


   return @dt
END
GO