Код

Create procedure _1sp_GetNextPeriod(@BaseDate DATETIME, @Period CHAR(1), @NewDate DATETIME OUTPUT) AS

SET NOCOUNT ON
SET DATEFIRST 1
DECLARE @BeginOfPeriod datetime
DECLARE @day integer

IF @Period='M' BEGIN
    SELECT @NewDate = DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BaseDate), '1753-02-01')
    RETURN
END


EXECUTE _1sp_GetBeginOfPeriod @BaseDate, @Period, @BeginOfPeriod OUTPUT
IF @Period='D'
    SELECT @NewDate=DATEADD(dd, 1,  @BeginOfPeriod)
ELSE IF @Period='W'
    SELECT @NewDate=DATEADD(wk, 1,  @BeginOfPeriod)
ELSE IF @Period='M'
    SELECT @NewDate=DATEADD(mm, 1,  @BeginOfPeriod)
ELSE IF @Period='Q'
    SELECT @NewDate=DATEADD(qq, 1,  @BeginOfPeriod)
ELSE IF @Period='Y'
    SELECT @NewDate=DATEADD(yy, 1,  @BeginOfPeriod)
ELSE IF @Period='T' BEGIN
    SELECT @day=DATEPART(dd, @BeginOfPeriod)
    IF @day>15 SELECT @NewDate=DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BeginOfPeriod), '1753-02-01')
    ELSE	 SELECT @NewDate=DATEADD(dd, 15, @BeginOfPeriod)
END
ELSE IF @Period='C' BEGIN
    SELECT @day=DATEPART(dd, @BeginOfPeriod)
    IF @day>20 SELECT @NewDate=DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BeginOfPeriod), '1753-02-01')
    ELSE	 SELECT @NewDate=DATEADD(dd, 10, @BeginOfPeriod)
END
ELSE IF @Period='F' BEGIN
    SELECT @day=DATEPART(dd, @BeginOfPeriod)
    IF @day>25 SELECT @NewDate=DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BeginOfPeriod), '1753-02-01')
    ELSE	 SELECT @NewDate=DATEADD(dd, 5,  @BeginOfPeriod)
END
ELSE SELECT @NewDate=CONVERT(datetime, '1753-01-01')
GO


Create procedure _1sp_GetBeginOfPeriod(@BaseDate DATETIME, @Period CHAR(1), @NewDate DATETIME OUTPUT) AS

SET NOCOUNT ON
SET DATEFIRST 1
DECLARE @Day int
IF @Period='M'
    SELECT @NewDate=DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BaseDate), '1753-01-01')
ELSE  IF @Period='D'
    SELECT @NewDate=@BaseDate
ELSE IF @Period='W'
    SELECT @NewDate=DATEADD(dd, -DATEPART(dw, @BaseDate)+1, @BaseDate)
ELSE IF @Period='Q'
    SELECT @NewDate=DATEADD(qq, DATEDIFF(qq, '1753-01-01', @BaseDate), '1753-01-01')
ELSE IF @Period='Y'
    SELECT @NewDate=DATEADD(yy, DATEDIFF(yy, '1753-01-01', @BaseDate), '1753-01-01')
ELSE IF @Period='T'
    BEGIN
	    SELECT @Day=DATEPART(dd, @BaseDate )
	    IF @Day>15 SELECT @Day=15
	    ELSE	 SELECT @Day=0
	    SELECT @NewDate=DATEADD(dd, @Day, DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BaseDate), '1753-01-01'))
    END
ELSE IF @Period='C'
    BEGIN
	    SELECT @Day=DATEPART(dd, @BaseDate )
	    IF	@Day>20  SELECT @Day=20
	    ELSE IF @Day>10  SELECT @Day=10
		ELSE		 SELECT @Day=0
	  SELECT @NewDate=DATEADD(dd, @Day, DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BaseDate), '1753-01-01'))
    END
ELSE IF @Period='F'
    BEGIN
	  SELECT @Day=DATEPART(dd, @BaseDate )
	  IF	@Day>25 SELECT @Day=25
	  ELSE IF @Day>20 SELECT @Day=20
	  ELSE IF @Day>15 SELECT @Day=15
	  ELSE IF @Day>10 SELECT @Day=10
	  ELSE IF @Day>5  SELECT @Day=5
	  ELSE		SELECT @Day=0
	  SELECT @NewDate=DATEADD(dd, @Day, DATEADD(mm, DATEDIFF(mm, '1753-01-01', @BaseDate), '1753-01-01'))
    END
ELSE SELECT @NewDate=CONVERT(datetime, '1753-01-01')
GO