Mysql两个表，获取没有相同值的数据

I have two table in my DB as table tbl_a and tbl_b which are having following data.

tbl_a

 tbl_a_id  u_id  a_name
     1      1      Joe
     2      1      Joel
     3      1      Joele
     4      1      Joelle
     5      3      Joeee

tbl_b

 tbl_b_id  u_id  a_name
     1      1      Joe
     2      1      Joel
     3      1      Joele
     4      1      Joelle
     5      3      Joeee
     5      1      Joeees
     5      1      Joeeess

How can I get the tbl_b.a_name values which are not present in the tbl_a table as a_name.

My desire output should be like,

Joeees

Joeeess

Right now I am having the following code.

 $qqq = $this->db->query("
    SELECT 
        tbl_b.a_name
    FROM tbl_b
    WHERE tbl.u_id='1'
 ");

  foreach($qqq->result() as $ggg)
  {
     echo $ggg->a_name;
  }

Thank in advance.

The simplest way is to use not exists:

select a.*
from tbl_a a
where not exists (select 1 from tbl_b b where b.b_name = a.a_name);

Try this

SELECT 
       DISTINCT tbl_b.a_name
    FROM tbl_b where tbl_b.a_name NOT IN (SELECT DISTINCT tbl_a.a_name from tbl_a) 

I got the solution thanks for the help anyways..

 SELECT 
    tbl_b.a_name
 FROM tbl_b
 WHERE tbl_b.u_id='1'
 AND NOT EXISTS (SELECT * FROM tbl_a WHERE tbl_a.u_id='1' AND tbl_b.a_name = tbl_a.a_name)

You can try not in same as follow:

SELECT * FROM `tbl_b`
where a_name not in (select DISTINCT a_name from tbl_a)

select a.*,b.*
from tbl_a a left join tbl_b b on a.u_id = b.u_id
where b.b_name != a.a_name

You can try this it may be useful and execute fast then other query.