select table1.*,table2.*,table3.*,table4.* from table1
inner join table2
inner join table3
inner join table4
correct, it is cartesian product, not cross product. thank you, varmadba :)
True, the cardinality is just the total product of the cardinalities of all involved tables. But this might be ok to him. So he would learn how to figure out the essential rows manually doing true handiwork.