Select only the last record for multiple values

Question

I have a table called "sessions" with say 4 columns like below

id  name s_time f_time
01  abc  10.15  10.45
02  abc  11.05  11.55
03  abc  12.18  13.46
04  abc  15.12  16.53
05  def  10.01  12.58
06  def  14.06  16.51
07  def  17.43  18.54
08  xyz  09.45  12.36
09  xyz  14.51  15.57
10  xyz  16.23  18.01

How can I get the last f_time for each name?

What I need is:

name f_time
abc  16.53
def  18.54
xyz  18.01

What am trying is this:

select name,f_time 
from sessions 
where name in ('abc','def','xyz') 
order by id DESC LIMIT 1;

but am only getting the finish time for the first name.

MariaDB 10.1.37

Answer 1

give your example data this should do it.

SELECT name, max(f_time) AS f_time
FROM sessions 
WHERE name IN ('abc','def','xyz') 
GROUP BY name 
ORDER BY name;

If you need to pick the f_time according to some other column it gets messy.

In Postgresql you can use the distinct on SQL extension.

SELECT DISTNICT ON (name)
    name, f_time
FROM sessions 
WHERE name IN ('abc','def','xyz') 
ORDER BY name, id desc;

i think there's also a way using window functions