>>And query:
>>Select * from Table1 ;
>>where Table1.Key1+Table1.Key2+Table1.Key3 NOT IN ;
>>(Select Table2.Key1+Table2.Key2+Table2.Key3 From Table2)
>>is notsatisfactory for me.
>>Do you understand me?
>
>Not exactly. It doesn't matter how many fields constitute primary key. And it doesn't matter how identical tables are. The only thing you should care is primary key which allow you to bring missing (or all minus missing, etc) records form one of the table. Maybe, you could give an example what records you really expect to retrieve.

Main thing is that there isn't one field as primary key, there is three!