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Employee active status for all Mondays in the year.

Interested in determining the active status of all of my employees for every Monday over a running two year (two years back from today) period.

I currently have the two code snippets:
(1) Direct selection of employees:
SELECT	employee_nbr,
		date_hire,
		term_date 
FROM	lawson_temp

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(2) CTE determining all Mondays for a quarter within a year:
;WITH Tally AS 
(SELECT TOP 366 n = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1 FROM sys.columns)
SELECT Mondays = AllDays
FROM Tally
	CROSS APPLY (SELECT DATEADD(day, n, 2013)) x(AllDays)
WHERE	(DATEPART(Quarter, AllDays) = 1) AND 
		(DATENAME(Weekday, AllDays) = 'Monday') AND 
		(DATEPART(YEAR, AllDays) = 2013)

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My question is how could I get a structure that would tell me each employee's active status in a 1 or 0 bit for each Monday over the last two years looking something like:

EmployeeNo, Date, bitStatus
70123,2013-01-07 00:00:00.000, 0
70123,2013-01-14 00:00:00.000, 1
70123,2013-01-21 00:00:00.000, 1
71230,2013-01-07 00:00:00.000, 1
71230,2013-01-14 00:00:00.000, 1
71230,2013-01-21 00:00:00.000, 0
72301,2013-01-07 00:00:00.000, 1
72301,2013-01-14 00:00:00.000, 0
72301,2013-01-21 00:00:00.000, 0

THANK YOU so much for any and all help you're able to lend!!
0
Levi Martin
Asked:
Levi Martin
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3 Solutions
 
Scott PletcherSenior DBACommented:
You really only have to calculate the first Monday date -- other Mondays can be calc'd by adding 7 day mutliples to that date.

For example:


IF OBJECT_ID(N'tempdb..#lawson_temp') IS NOT NULL
    DROP TABLE #lawson_temp
CREATE TABLE #lawson_temp (
    employee_nbr int,
      date_hire datetime,
      term_date datetime,
    )
INSERT INTO #lawson_temp
SELECT 70123, '20110112', '20130511'
UNION ALL
SELECT 72301, '20120416', '20130118'
/*
70123,2013-01-07 00:00:00.000, 0
70123,2013-01-14 00:00:00.000, 1
70123,2013-01-21 00:00:00.000, 1
71230,2013-01-07 00:00:00.000, 1
71230,2013-01-14 00:00:00.000, 1
71230,2013-01-21 00:00:00.000, 0
72301,2013-01-07 00:00:00.000, 1
72301,2013-01-14 00:00:00.000, 0
72301,2013-01-21 00:00:00.000, 0
*/            

DECLARE @start_date datetime
DECLARE @end_date datetime

SET @end_date = DATEADD(DAY, DATEDIFF(DAY, 0, GETDATE()), 0)
SET @start_date = DATEADD(DAY, 1, DATEADD(YEAR, -2, @end_date))
            
;WITH cte_First_Monday AS (
    SELECT DATEADD(DAY, DATEDIFF(DAY, 0, DATEADD(DAY, 6, @start_date)) / 7 * 7, 0) AS first_monday
),
cte_Digits AS (
    SELECT 0 AS digit UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL
    SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL
    SELECT 8 UNION ALL SELECT 9
),
cte_Tally AS (
    SELECT ones.digit + tens.digit * 10 + hundreds.digit * 100 AS tally
    FROM cte_Digits ones
    CROSS JOIN cte_Digits tens
    INNER JOIN cte_Digits hundreds ON
        hundreds.digit <= (DATEDIFF(DAY, @start_date, @end_date) + 1) / 7
    WHERE
        ones.digit + tens.digit * 10 + hundreds.digit * 100 BETWEEN 0 AND (DATEDIFF(DAY, @start_date, @end_date) + 1) / 7
)
SELECT
    lt.Employee_Nbr,
    DATEADD(DAY, ct.tally * 7, cfm.first_monday) AS Monday_Date,
    CASE WHEN lt.date_hire <= DATEADD(DAY, ct.tally * 7, cfm.first_monday)
          AND (lt.term_date IS NULL OR lt.term_date >= DATEADD(DAY, ct.tally * 7, cfm.first_monday))
         THEN 1 ELSE 0 END AS BitStatus,
    lt.date_hire, --for testing, to verify BitStatus, remove later
    lt.term_date --for testing, to verify BitStatus, remove later
FROM cte_Tally ct
CROSS JOIN cte_First_Monday cfm
LEFT OUTER JOIN #lawson_temp lt ON
    lt.date_hire <= @end_date
--SELECT      employee_nbr,            date_hire,            term_date FROM      lawson_temp
ORDER BY
    lt.employee_nbr, ct.tally
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DOSLoverCommented:
I will just use what you have already done, for getting Mondays. Then combine that with Lawson_Temp table. I also assume date_hire and term_date are in datetime format. Also please note that I am using 731 days for counting two years back from today, and removed condtions for quarter=1 and year=2013. Some of these will have to be tweaked based on your requirement. For example, Do you want to consider Term_Date as 'Active' date? Date comparison will have to be tweaked in that case.
Select a.Employee_Nbr ,a.Date_Hire, a.Term_Date , AllDays
          ,CASE WHEN AllDays >= a.Date_Hire and ALLDays <= a.Term_Date Then 1
  	   ELSE 0 
          END as isActive
  from Lawson_Temp a,
      (SELECT AllDays
         FROM (SELECT TOP 731 n = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1 FROM sys.columns) as Tally
              CROSS APPLY (SELECT DATEADD(day, -n, GETDATE() )) x(AllDays)
        WHERE  (DATENAME(Weekday, AllDays) = 'Monday')
      ) MyDays

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PortletPaulCommented:
By building a CTE backwards from the most recent Monday, of only Monday dates, for the past 2 years, then count these per employee where the Monday is after or equal to date_hire and a Monday is before term_date (or term_date is null)

if term_date itself is considered active, include <= in line 27 below
-- set number of years
declare @numYears as int
set @numYears = 2

-- next get recent Monday
declare @BeginsAt as datetime

-- truncate time from getdate()
set @BeginsAt = dateadd(day, datediff(day,0, getdate() ), 0)

-- get Monday using modulus
set @BeginsAt = dateadd(day,(-datediff(day,0,@BeginsAt) % 7),@BeginsAt) 

;with Ranger (id, StartAt)
as (
    /* recursively build CTE of Mondays */
    select 1 as id, @BeginsAt
    union all
    select (id + 1) , dateadd(day,-7,StartAt)
    from Ranger
    where dateadd(day,-7,StartAt) >= dateadd(year,-@numYears,@BeginsAt)
    )
select
    employee_nbr
    /* count number of Mondays over span date_hire ... term_date */
  , count( case
             when startat >= date_hire and startat < term_date then startat 
             when startat >= date_hire and term_date is null   then startat
           end 
          ) as active_mondays
  , min(date_hire) as date_hire
  , max(term_date) as term_date
from Ranger
cross join lawson_temp
group by
    employee_nbr

OPTION ( MAXRECURSION 110 ) --  >= (@Numyears * 55)

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available to try at http://sqlfiddle.com/#!3/f6859/2
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PortletPaulCommented:
Having posted the above I realize you didn't want a summary (sorry, bad assumption)
So here's the table of details using the same basic structure
-- set number of years
declare @numYears as int
set @numYears = 2


-- next get recent Monday
declare @BeginsAt as datetime

-- truncate time from getdate()
set @BeginsAt = dateadd(day, datediff(day,0, getdate() ), 0)

-- get Monday using modulus
set @BeginsAt = dateadd(day,(-datediff(day,0,@BeginsAt) % 7),@BeginsAt) 


;with Ranger (id, StartAt)
as (
    /* recursively build CTE of Mondays */
    select 1 as id, @BeginsAt
    union all
    select (id + 1) , dateadd(day,-7,StartAt)
    from Ranger
    where dateadd(day,-7,StartAt) >= dateadd(year,-@numYears,@BeginsAt)
    )
select
    employee_nbr
  , startat as [Date]
  , case
        when startat >= date_hire and startat < term_date then 1 
        when startat >= date_hire and term_date is null   then 1
        else 0
     end 
     as bitStatus
from Ranger
cross join lawson_temp
-- order by bitStatus, employee_nbr -- as required

OPTION ( MAXRECURSION 110 ) --  >= (@Numyears * 55)

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this variant http://sqlfiddle.com/#!3/f6859/4
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DOSLoverCommented:
After looking at previous post, I realize we need to account for Term_date that can be NULL. I am using <= for comparing against ter_date, because, an employee is technically 'Active', though partly, on the day of term_date. Here is the modified code:
Select a.Employee_Nbr ,a.Date_Hire, a.Term_Date , AllDays
          ,CASE WHEN AllDays >= a.Date_Hire and (ALLDays is NULL OR ALLDays <= a.Term_Date) Then 1
  	   ELSE 0 
          END as isActive
  from Lawson_Temp a,
      (SELECT AllDays
         FROM (SELECT TOP 731 n = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1 FROM sys.columns) as Tally
              CROSS APPLY (SELECT DATEADD(day, -n, GETDATE() )) x(AllDays)
        WHERE  (DATENAME(Weekday, AllDays) = 'Monday')
      ) MyDays 

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Levi MartinSenior Data AnalystAuthor Commented:
Thank you to all three of you for your quick feedback and shared expertise! It was very, very helpful to see the two options and to educate myself from there...will defintiely make me a better T-SQL developer! THANK YOU!!

The CTEs are a great idea that work very well but more code than I was hoping to implement into my current query structures; the solution provided by DOSLover was concise. Modified the date comparison and opened query to count rolling decade as such:

SELECT      a.employee_nbr,
            a.date_hire,
            a.term_date,
            AllDays,
            (CASE WHEN AllDays >= a.Date_Hire OR AllDays <= a.term_date THEN 1 ELSE 0 END) AS isActive
FROM      lawson_temp a,
            (SELECT AllDays
         FROM (SELECT TOP 3651 n = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1 FROM sys.columns) As Tally
              CROSS APPLY (SELECT DATEADD(day, -n, GETDATE() )) x(AllDays)
             WHERE  (DATENAME(Weekday, AllDays) = 'Monday')) MyDays  
ORDER BY      a.employee_nbr
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PortletPaulCommented:
don't you need to cater for a NULL term_date?

most HR systems I've worked with have that field as NULL (until a termination occurs)
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Levi MartinSenior Data AnalystAuthor Commented:
Yes, I added that back after my  point award post this morning as such:

SELECT      TOP (100) PERCENT lawson_temp.employee_nbr AS EmployeeNo,
            (CASE WHEN lawson_temp.adjusted_service_date IS NULL THEN lawson_temp.date_hire ELSE lawson_temp.adjusted_service_date END) AS HireDate,
            lawson_temp.term_date AS TermDate,
            AllDays AS MondayDate,
            (CASE WHEN AllDays >= lawson_temp.date_hire AND (lawson_temp.term_date IS NULL OR AllDays <= lawson_temp.term_date) THEN 1 ELSE 0 END) AS ActiveStatus

FROM      lawson_temp,
            (SELECT AllDays
         FROM (SELECT TOP 3651 n = ROW_NUMBER() OVER (ORDER BY (SELECT NULL))-1 FROM sys.columns) AS Tally
              CROSS APPLY (SELECT DATEADD(DAY, -n, GETDATE() )) x(AllDays)
             WHERE  (DATENAME(Weekday, AllDays) = 'Monday')) MyDays  

ORDER BY      lawson_temp.employee_nbr

Great catch!
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Scott PletcherSenior DBACommented:
I had the NULL check for term_date in my initial query.

CTE disqualification kind of ironic, since I'm not a big fan of CTEs ... I used them only because you used one in your initial post :-) .
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Levi MartinSenior Data AnalystAuthor Commented:
Great post too; very appreciative! Perhaps I could have provided a better distro of awarded points?

Taking out the CTE wasn't an initial thought of mine but the latest post from DOSLover provided me something I hadn't thought of which placed easier into my reporting. I've had many developers lean me away from CTEs and the solution was great...every post helped me learn which I have much to do.
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PortletPaulCommented:
there is another factor to consider:
CROSS APPLY (SELECT DATEADD(DAY, -n, GETDATE() )) x(AllDays)

that does not strip time back to 00:00:00 from getdate() which may produce unwanted results
you could add to that logic by:
CROSS APPLY (SELECT DATEADD(DAY, -n, dateadd(day, datediff(day,0, GETDATE() ), 0)  )) x(AllDays)

for the heck of it: an alternative without CTE, using master.dbo.spt_values which returns just Mondays for the past 2 years
SELECT TOP (100) PERCENT -- I am dubious about the use of TOP 100 PERCENT
      lawson_temp.employee_nbr AS EmployeeNo
    , (
        CASE 
            WHEN lawson_temp.adjusted_service_date IS NULL
                THEN lawson_temp.date_hire
            ELSE lawson_temp.adjusted_service_date
            END
        ) AS HireDate
    , lawson_temp.term_date AS TermDate
    , MDays.MondayDate
    , (
        CASE WHEN MDays.MondayDate >= lawson_temp.date_hire
                AND (
                    lawson_temp.term_date IS NULL
                    OR MDays.MondayDate <= lawson_temp.term_date
                    ) THEN 1 ELSE 0 END
        ) AS ActiveStatus
FROM lawson_temp
CROSS JOIN (
            SELECT
              number
            , dateadd(DAY, datediff(DAY,-7, getdate() ) - (number*7) - (datediff(DAY,0, getdate() ) % 7), 0) as MondayDate
            FROM master.dbo.spt_values
            WHERE  TYPE = 'P'
            AND number BETWEEN 1 AND datediff(DAY,dateadd(YEAR,-2,getdate()),getdate()) / 7
           ) as Mdays
ORDER BY lawson_temp.employee_nbr, MDays.MondayDate

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http://sqlfiddle.com/#!3/1fa93/7846
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