Mysql Select distinct records from latest dates only

Question

This is my table structure -

TABLE : COURSE_LOG

-----------------------------------------------------
|   ID   |   USERNAME   |  COURSE_ID   |    LDATE   |         


        

Answer 1

You can use MAX:

SELECT  COURSE_ID
    , MAX(LDATE) AS LDATE
    FROM COURSE_LOG
    WHERE USERNAME = 'user1'
    GROUP BY COURSE_ID;

Answer 2

Try this query

If you want only for user1 then use this query:

select username, course_id, max(ldate) as date
from tbl 
where username='user1'
group by username, course_id

SQL FIDDLE

| USERNAME | COURSE_ID |       DATE |
-------------------------------------
|    user1 |        22 | 2013-06-03 |
|    user1 |        54 | 2013-06-03 |

If you want to find the latest date for all users then use this query

select username, course_id, max(ldate) as date
from tbl 
group by username, course_id

In this query data of user2 will also be included

| USERNAME | COURSE_ID |       DATE |
-------------------------------------
|    user1 |        22 | 2013-06-03 |
|    user1 |        54 | 2013-06-03 |
|    user2 |        71 | 2013-06-04 |