How to select values from two different tables in SQL

Question

I have two tables in my SQL Server database. The first is Test1 and second is Test2. There is a column RegNo in both tables.

Now I

Answer 1

select
    Test1.SurName,
    Test2.Class,
    Test2.Medium
from Test1
inner join Test2
on Test1.RegNo = Test2.RegNo

And if you want to select your data for a particular RegNo, just add a WHERE clause to the end, like so:

select
    Test1.SurName,
    Test2.Class,
    Test2.Medium
from Test1
inner join Test2
on Test1.RegNo = Test2.RegNo
where Test1.RegNo = 123456   -- or whatever value/datatype your RegNo is