情景：每天收集到很多意思相近的新聞，按照時間，取每天的第一條

1.group by 按照時間分組
select distinct substring(pubTime,1,10) pubTime,max(title_ch) from news
where title_ch != ’ ’
group by substring(pubTime,1,10)
order by substring(pubTime,1,10)

2.rank_over 為每組按照制定順序打標簽(排序)，最終取每組前N
select * from (
select pubTime,title_ch,rank() over(partition by pubTime order by title_ch desc,pubTime asc) as rank_over from
(
select distinct substring(pubTime,1,10) pubTime,title_ch from news where title_ch != ’ ’ and category = ‘belt_and_road’ and media = ‘news18.com’ order by pubTime asc
)a
)b
where rank_over <= N

總結

以上是生活随笔為你收集整理的分组取每组的第一条或前N条的全部內容，希望文章能夠幫你解決所遇到的問題。

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