Question

I have two tables:

Holiday and EmpLog

I need to select only the dates that are not present in Emplog (those days are WEEKDAYS and NOT equal to Holidays ONLY)

For example, I haven’t logged this day: Dec 18, 2012.

So the output will be dec 18,2012

Answer 1

From the question, I assume the following:

1. You have an EmpLog table, that has the datestamp of all the dates the Employee was present.
2. You have a Holiday table that has a list of dates that were either Weekends or Holidays
3. You need to find out all the dates that were working days, but a given employee was not logged

If these assumptions are correct, then this code will work:

--Declare variables to hold date values 
DECLARE @MyDate    DATETIME, 
        @FirstDate DATETIME, 
        @LastDate  DATETIME 

SELECT @MyDate = Getdate() -- OR Pass whatever date you want 

--Populate variable with values of first date and last date of the given month 
SELECT @FirstDate = CONVERT(VARCHAR(25), Dateadd(dd, -( Day(@mydate) - 1 ), 
                                         @mydate), 
                           101), 
       @LastDate = CONVERT(VARCHAR(25), Dateadd(dd, -( Day( 
                                        Dateadd(mm, 1, @mydate)) ), 
                                                    Dateadd(mm, 1, @mydate)), 
                   101) 

--Declare table variable to hold date values for the entire month 
DECLARE @AllDates TABLE 
  ( 
     datevalue DATETIME 
  ) 
DECLARE @Lastday INT 

SET @Lastday = Datepart(d, @LastDate) 

DECLARE @Days INT 

SET @Days = 1 

-- Populate table variable with all days of the month 
WHILE @Days <= @Lastday 
  BEGIN 
      INSERT INTO @AllDates 
      SELECT @FirstDate 

      SET @FirstDate = Dateadd(d, 1, @FirstDate) 
      SET @Days = @Days + 1 
  END 

--Query joining the EmpLog table and Holiday Table, using Left Outer Join  
SELECT AD.datevalue 
FROM   @AllDates AD 
       LEFT OUTER JOIN emplog EL 
                    ON AD.datevalue = EL.datevalue 
       LEFT OUTER JOIN holiday H 
                    ON AD.datevalue = H.datevalue 
-- Where clause to return only dates that do not appear in EmpLog or Holiday tables 
WHERE  EL.datevalue IS NULL 
       AND H.datevalue IS NULL  

Hope this helps.

Rajan