Query Question about 4 tables

[JOM]

I have 4 tables,
tbl1 has fieldX, filedY and fieldZ
tbl2 has fieldA and fieldB
tbl3 has fieldC
tbl4 has fieldD

What I want to archieve is as follows
tbl1.fieldX + tbl2.fieldY - tbl3.fieldZ
+tbl2.sum(fieldA)+tbl3.sum(fieldc)=tbl4.fieldD

part2:
tbl3.fieldC=Avg(tbl4.fieldD)
Please help!

 

[Ofer]

How do you link the tables?
Or mybe there is only one record in each table, except of the table where
you sum the values?
Do you sum all the records in the table, or there is a filter?

We need more details.

 

[JOM]

These are different fields obvously there is a link that will link all the
tables and that would be EmplID I only grabbed a few fields from each of the
table. What am trying to find out is how I can grab a few fields that can be
calculated and paste the infor in a different table..