SQL查询同一用户的最后日期

Question

I have a table with following data. ID, date and type are all primary key. ID is person, type is for work type.

id     date     Type
--------------------------
6   |  2011   |  2
6   |  2012   |  2
6   |  2012   |  3
6   |  2012   |  5
7   |  2013   |  1
7   |  2016   |  1
etc..

I want to create a query that would show both id 6 that have difference type, and take the last date if there is tow row for same ID with same type. The result should show same as that.

id     date     Type
--------------------------
6   |  2012   |  2
6   |  2012   |  3
6   |  2012   |  5
7   |  2016   |  1
etc..

Answer 1

You can do this with a correlated subquery:

select t.*
from t
where t.date = (select max(t2.date) from t t2 where t2.id = t.id and t2.type = t.type);

Answer 2

Another way to do it :

select a.id, b.date, a.type
 from 
(
    select distinct id, type 
    From Test1 
) a
INNER JOIN 
(
    select distinct id, max(date) date
    From Test1 
    group by id
) b 
on a.id = b.id