MySQL Select rows on first occurrence of each unique value
You could use a filtering join:
select *
from (
select cid
, min(time) as min_time
from YourTable
group by
cid
) filter
join YourTable yt
on filter.cid = yt.cid
and filter.min_time = yt.time
Try this one,
SELECT *
FROM tableName a
INNER JOIN (
SELECT cid, MIN(`time`) AS MinTime
FROM tableName
GROUP BY cid
) b
ON a.CID = B.cid AND a.time = b.MinTime
In MySQL 8, you would use window functions for this
SELECT cid, pid, rid, clink, time, snippet
FROM (
SELECT t.*, ROW_NUMBER() OVER (PARTITION BY cid ORDER BY time) rn
FROM t
) t
WHERE rn = 1
mysql has a "cheat" for this:
select *
from mytable
group by cid;
That's all you need, because in mysql it allows you to not aggregate the non-grouped-by columns (other databases would throw a syntax error), in which case it outputs only the first occurrence of each group-by value(s). Note though that this won't guarantee the way in which the "first" occurrence is determined (it will be just how the rows are read in)
If you want a particular first occurrence, sort first, then apply the group-by cheat:
select *
from (
-- order by the "time" column descending to get the "most recent" row
select * from mytable order by time desc
) x
group by cid