Normally, whether it is the sql statement or the application interface, you test for null - for example, like isnull...

There is an isnull function within sql server - download books online (the sql server reference for sql server), which you can use within your sql statement.

I realize this is months later, but for the benefit of anyone else scanning these forums...

Null fields in Access and SQL Server are normal. They represent a lack of data. Sophisticated development environments do *not* hide this fact. The reason you're having a problem is because you're not testing for the a null value. I would imagine you're doing something like

intval := Query1.FieldByName( 'field1' ).AsInteger;

or something similar. If it's possible that your field hasn't been populated yet, it could come back as a null value, in which case you may a conversion problem. What you're really seeing is the field value, which is a variant, attempting to convert a variant null to some other datatype. If you want to familiarize yourself with what's going on behind the scenes, look in the DB.PAS unit of your VCL.

In the meantime, if the value you're testing could contain a null, and that null could throw off your program, test for the null condition using the IsNull property of the TField class. In other words:

if ( not Query1.FieldByName( 'field1' ).IsNull ) then
....

Good luck.

:cool: