Date Query NOT WORKING Right

[maurices5000]

The following query is supposed to select the EmployeeID and Hiredate along with number of years hired, year(now)-year(hiredate) as Years where the hire date is exactly 6 months ago or the current month. (The second part of the where clause appears to work. It simply says that years hired should be greater than 10)

Six months ago would be November. The current month of course is May.

However, this query identifies dates that appear on 12/1 which is an error.

I'm assuming this is precision error. But I don't know.

SELECT EmployeeID, HireDate, year(now)-year(hiredate) as Years
FROM Employee
WHERE (Month(Now-HireDate)=6 Or Month(Now)=Month(HireDate)) And (year(now)-year(hiredate)>10);

Query Results:

EmployeeID  HireDate	Years
1	    11/9/1994	12
10	    11/20/1991	15
21	    11/16/1989	17
88	    5/16/1989	17
124	    12/1/1994	12
133	    5/16/1991	15

[DKenny]

Change

WHERE (Month(Now-HireDate)=6 Or Month(Now)=Month(HireDate))

to

WHERE ((Month(Now) -Month (HireDate)) IN (6,-6) Or Month(Now)=Month(HireDate))

[maurices5000]

Thanks! I'll give it a try! Why is there a difference? What went wrong?

The above code that i used came from microsoft's website.

Thanks again!

[maurices5000]

That worked! Thanks!

I'm still wondering why there was a difference. This is such an easily overlooked issued that it could cause problems if not thoroughly checked.

[DKenny]

Month(Now-HireDate) is going to evaluate as follows

1/ Determine the number of days between Now and HireDate. (giving an integer value of days)
2/ Probably convert that integer value to a date, based on the 1st date in the system calendar
3/ Determine the Month of that date.

This is clearly goign to give wrong answers. My solution was to convert both dates to months and then subtract the resulting month numers.
The resaon for the IN (6,-6) is that Jan (1) and July (7) are six months apart but would evalute to -6.

[maurices5000]

Thanks very much!

Great explanation.