The better way I suggest you is to create a separate table let say with three fields called EmployeeLeaves, and the three fileds are Employee Id (Foreign key), Month(Int data type), LeaveCount(int data type) and than get a sence to have the no. of days for particular month by the following script.
DECLARE @StartDate DATETIME
DECLARE @BreakDate DATETIME
DECLARE @EndDate DATETIME
DECLARE @Year INT
DECLARE @Month INT
SET @StartDate = '2013-01-25'
SET @EndDate = '2013-02-03'
IF MONTH(@StartDate) <> MONTH(@EndDate)
BEGIN
SET @Month = MONTH(@StartDate) + 1
SET @Year = YEAR(@StartDate)
IF @Month = 12
BEGIN
SET @Year = @Year + 1
END
SET @BreakDate = CONVERT(VARCHAR(100),@Year) + '-' + CONVERT(VARCHAR(100),@Month) + '-01'
SELECT DATEDIFF(DAY,@StartDate,@BreakDate)
SELECT DATEDIFF(DAY,@BreakDate,@EndDate) + 1
END
You needs to save data accordingly.