MySQL Select Distinct Question

I want to return all columns from a table, but only for the 'unique' or 'distinct' users.

I want to grab all the distinct users from a table, but return all columns.

I will be sorting the table by a timestamp, so as to grab the 'first' entry of each distinct user开发者_StackOverflow社区.

Any Ideas?

---

You should post the table definition but more or less it should be possible using a GROUP BY.

SELECT col1, col2, col3, MIN(timestamp)
FROM   users
GROUP BY
       col1, col2, col3

If any of your other columns also contains variable data (as they actually should in a normalized table), you have to make a choice on what aggregrate function you wish to use on them.

SELECT col1, col2, col3, MAX(var1), AVG(var2), ..., MIN(timestamp)
FROM   users
GROUP BY
       col1, col2, col3

---

select * from table group by userid order by time;

Don't forget to rename userid and time to match your column names

---

Have you tried using GROUP BY, i.e.

SELECT * FROM users GROUP BY id ORDER BY ...

Generally it should work, but you haven't mentioned any structure..

---

You don't really need to group. What you want is select every record in your table that doesn't have another record for the same user with a lesser (or greater) timestamp

select * from my_table t1
where not exists (select 1 from my_table t2
                   where t1.user = t2.user
                     and t1.time < t2.time)

Be sure to have indexes on user and time columns

---

select * 
from table a,
(select min(timestampfield) as ts, userid as userid
from table
group by userid) b
where a.userid = b.userid and a.ts = b.ts