how to have a double while loop in sql server 2008

Question

I'm developing an appointment calendar application. Still newbie here.

I need help in this area.

I need to have a double looping in columns (`calendarID, Slot, AppointmentDate').

The 'slot' column will have a value of 1,2,3,4,5,6,7,8 upto 28 repeatedly while the calendarID will continuously loop to 868 value. The Appointment date will have the value from 1 Aug2013 to 31 Aug 2013 (actually I'm planning to do this for 1 whole year)

expected result

calendarID | Slot       |  AppointmentDate      
----------------------------------------------  
    1          | 1         | 1 Aug 2013  
    2          | 2         | 1 Aug 2013    
    3          | 3         | 1 Aug 2013   
    4          | 4         | 1 Aug 2013   
    5          | 5         | 1 Aug 2013   
    6          | 6         | 1 Aug 2013    
    7          | 7         | 1 Aug 2013   
    8          |..until 28 | 1 Aug 2013 
    9          | 1         | 2 Aug 2013    
    10         | 2         | 2 Aug 2013
    11         | 3         | 2 Aug 2013  
    ...until   
    868        | n         | n Month 2013  

Here is my code that I try seems I'm very far from my desired output. I edited the code provided by Astrand

DECLARE @tblCalendar TABLE(CalendarEntryID INT,
    Slot INT,  ADate Varchar(50))

DECLARE @x int, @y int , @d INT

SET @X = 1 SET @y = 1 SET @d = 1

WHILE @X <= 868
BEGIN 

    WHILE  @Y <=28 AND @d <=31 AND @X <= 868 --LOOP FOR SLOT COLUMN
        BEGIN

        INSERT INTO @tblCalendar (CalendarEntryID,Slot, ADate)
        Values (@x, @y,@d +'/Aug/2013')
                SET @y = @y + 1
                SET @x = @x + 1
        SET @d = @d + 1 
           END
    SET @y = 1  
END

SELECT  *
FROM    @tblCalendar

sorry for the trouble of asking and editing my original post.

Answer 1

OK, this will get you the desired result, but it is questionable. I will try and improve it a bit after that.

DECLARE @tblCalendar TABLE(
        CalendarEntryID INT,
        Slot INT
)

DECLARE
@x int, @y int

SET @X = 1 SET @y = 1

WHILE @X <= 100
BEGIN 

    WHILE @Y <=8 AND @X <= 100--LOOP FOR SLOT COLUMN
            BEGIN
            INSERT INTO @tblCalendar (CalendarEntryID,Slot)
            Values (@x, @y)

                SET @y = @y + 1
                SET @x = @x + 1
            end

    SET @y = 1
END


SELECT  *
FROM    @tblCalendar

Another approach would be to make use of an IDENTITY COLUMN

Something like

DECLARE @tblCalendar TABLE(
        CalendarEntryID INT IDENTITY(1,1),
        Slot INT
)

DECLARE
@x int, @y int

SET @X = 1 SET @y = 1

WHILE @X <= 100
BEGIN 

    WHILE @Y <=8 AND @X <= 100--LOOP FOR SLOT COLUMN
            BEGIN
            INSERT INTO @tblCalendar (Slot)
            Values (@y)

                SET @y = @y + 1
                SET @x = @x + 1
            end

    SET @y = 1
END


SELECT  *
FROM    @tblCalendar

But personally I would have gone for

DECLARE @Max INT = 100,
        @MaxGroup INT = 8

    ;WITH Val AS (
            SELECT  1 CalendarEntryID
            UNION ALL
            SELECT  CalendarEntryID + 1
            FROM    Val
            WHERE   CalendarEntryID + 1 <= @Max
    )
    SELECT  CalendarEntryID,
            ((CalendarEntryID - 1) % @MaxGroup) + 1 Slot
    FROM    Val
    OPTION (MAXRECURSION 0)

Answer 2

well since it's SQL I don't think you have to do loop. You can generate this data with recursive CTE easily:

with cte as (
    select 1 as calendarID
    union all
    select calendarID + 1
    from cte1
    where calendarID < 100
)
select
    CalendarID, (CalendarID - 1) % 8 + 1
from cte
order by CalendarID

sql fiddle demo