sqlite 相当于 row_number() over ( partition by ...? [英] sqlite equivalent of row_number() over ( partition by ...?

问题描述

我想知道是否可以使用单个 sqlite 语句执行以下操作:

I'd like to know if it's possible to do the following using a single sqlite statement:

我的桌子看起来像这样:

My table looks something like this:

|AnId|UserId|SomeDate|SomeData|
|123 |A     |1/1/2010|aadsljvs|
| 87 |A     |2/9/2010|asda fas|
|193 |A     |2/4/2010|aadsljvs|
|927 |A     |7/3/2010|aadsasdf|
|816 |B     |1/1/2010|aa32973v|
|109 |B     |7/5/2010|aaasfd10|
| 39 |B     |1/3/2010|66699327|
...

每一行都有一个唯一的 ID、一个用户 ID、一个日期时间值和一些其他数据.

Each row has a unique id, a user id, a datetime value, and some other data.

我想删除记录，以便根据 SomeDate每个用户保留最新的 10 条记录.

I'd like to delete records so I keep the latest 10 records per user, based on SomeDate.

在 sql server 中我会使用这样的东西:

In sql server I'd use something like this:

delete d
from data d
inner join (
    select UserId
        ,  AnId
        ,  row_number() over ( partition by UserId order by SomeDate desc ) 
              as RowNum
    from data 
) ranked on d.AnId = ranked.AnId
where ranked.RowNum > 10

有没有办法在 sqlite 中做到这一点?有多个记录具有相同 SomeDate 的边缘情况并不是特别担心，例如如果我保留所有这些记录就好了.

Is there a way to do this in sqlite? The edge case where there are several records with the same SomeDate isn't a particular worry, e.g. if I keep all those records that'd be fine.

推荐答案

我知道这个问题很老了，但是下面的 SQLite 语句将执行 Rory 最初在一个语句中要求的操作 - 删除给定 UserId 的所有记录不是该 UserId 的 10 条最新记录(基于 SomeDate).

I know this question is old, but the following SQLite statement will do what Rory was originally asking for in one statement - Delete all records for a given UserId that are not the 10 most recent records for that UserId (based on SomeDate).

DELETE FROM data
WHERE AnId IN (SELECT AnId
               FROM data AS d
               WHERE d.UserId = data.UserId
               ORDER BY SomeDate DESC
               LIMIT -1 OFFSET 10)

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