Question

There are two tables which have a relation via a distinct so called PK.

Email     Gender  
[e-mail]    12345  
[e-mail]    12365

PK     String    
12345  MALE  
12365  FEMALE

What would a query look like to get E-Mail and the String of the gender?

 select 
  user.Email,
  users.Gender
from
  users,
values

Answer 1

You will want to JOIN the two tables. My suggestion would be to use ANSI JOIN syntax like INNER JOIN or LEFT JOIN instead of using a comma between the tables, similar to this:

select u.Email, v.String
from users u
inner join value v
   on u.Gender = v.PK

See SQL Fiddle with Demo

If you are confused about JOIN syntax, here is a great visual explanation of joins