If you want a count of all the combinations, just multiply the count of distinct table 1 values times the count of distinct table 2 values.

declare @table1 table (value1 char(1))

declare @table2 table (value2 char(1))

insert into @table1

values ('A'),('A'),('B'),('C'),('D'),('D'),('A'),('A') -- 4 distinct values

insert into @table2

values ('X'),('Y'),('Y'),('Y'),('Z'),('1'),('2'),('3') -- 6 distinct values

select (select count(distinct value1) total1 from @table1) *

(select count(distinct value2) as total2 from @table2) as Combinations

edit: simplified final query