group By 分组对查询出来的信息取第一条？

[愿你活成你喜欢的模样]

[RINK_1]

SELECT * FROM SKILL A
WHERE NOT EXISTS (SELECT 1 FROM SKILL WHERE USERID=A.USERID AND ID<A.ID)

[吉普赛的歌]

select * from (
	select 
		row_number() over(partition by userId order by skillName) as rid
		,*
	from skill
) as tt
where tt.rid=1

[二月十六]

SELECT skill.*
FROM skill
    JOIN
    (SELECT userid, MIN(id) id FROM skill GROUP BY userid) t
        ON t.id = skill.id