How can i filter data in block which built on table?
I want to show those data which fulfil statement from
the parent table (there is join condition between tables, but not blocks)

EX.
I have 2 tables: TAB1(A-primary key,B-foreign key,C)
TAB2(B-primary key,D,E)
That means that TAB2 is parent table

I built 2 blocks in Forms :TAB1,:TAB2 (but not joined them)
First i go to block :TAB1 and want to show all records
where D is null (D is a column of TAB2)