Appending Unique Records into a Table

I'm trying to append LastLogin_Date table with only unique records based on LastLogin_Date field.

If I run following query, it returns 'Record is deleted'.

INSERT INTO LastLogIn_SnapShots ( Name, Surname, Forename, LastLogin_Date )

SELECT dbo_Site.Name, dbo_AppUser.Surname, dbo_AppUser.Forename, dbo_AppUser.LastLogin_Date

FROM dbo_AppUser LEFT JOIN dbo_Site ON dbo_AppUser.Employee_Site_ID = dbo_Site.ID

WHERE ((dbo_AppUser.LastLogin_Date Not In (SELECT LastLogin_Date FROM LastLogIn_SnapShots WHERE LastLogin_Date is not null)) AND (dbo_AppUser.Employment_End) Is Null);

Obviously, problem lies in WHERE clause, but if I turn it in simple SELECT query it pulls correct data.

SELECT LastLogin_Date
FROM dbo_AppUser
WHERE ((LastLogin_Date Not In (SELECT LastLogin_Date FROM LastLogIn_SnapShots WHERE LastLogin_Date is not null)) AND (dbo_AppUser.Employment_End) Is Null);

Please help to identify the problem.

'Record is deleted' doesn't seem to be a sql server error.

You have 2 conditions in your where clause. Try running the query with one condition at a time to see which condition is not returning the expected results.

No, it isn't SQL server error, it is Access.

Both conditions seems to work fine, see the SELECT query.

First condition doesn't work in the append query, but if I make select query (second) out of it, it works perfectly well. Any ideas why this is happening?

So the only difference between your Insert query and the Select statement is the LEFT JOIN. Take another look at that and the data in that table.

It pulls site name from another table based on its ID. Why would this be a problem?

Any ideas, please?