Pls Explain the join mechanism on these two tables

select * from tbl_singlecolA

Result Set:

id
1
1
1
1

select * from tbl_singlecolB

Result Set:

id
1
1
1
1
1
1
1

select * from tbl_singlecolA A
join tbl_singlecolB B
on A.id=B.id

Result is showing as cartesian product of two tables ., 28 rows. I have expected 4 rows. Please explain the reason?