从 table 中删除用户记录很少的行

Question

有这个table:

 id    |    lat     |    lon     | timestamp  
---------+------------+------------+------------
 5590761 | 41.0106651 | -8.4618407 | 1491071642
 5590761 | 41.0088282 | -8.4613129 | 1491071670
 5590761 | 41.0081011 | -8.4626845 | 1491071763
 5590761 |  41.008415 | -8.4621233 | 1491071767
 5590761 | 41.0084717 |   -8.46211 | 1491071768
 5590761 |  41.008525 | -8.4620333 | 1491071769
 5590761 |   41.00859 | -8.4619783 | 1491071770
 5590761 |  41.008635 |  -8.461875 | 1491071771
 5590761 | 41.0087083 | -8.4616717 | 149107177

有些记录的实例很少。我想删除唯一 id 计数小于 10 的所有记录。

Answer 1

您可以在 delete 中使用子查询：

delete from t
    where t.id in (select t2.id
                   from t t2
                   group by t2.id
                   having count(*) < 10
                  );

如果只想删除 select 查询中的行，可以使用 window 函数：

select t.*
from (select t.*, count(*) over (partition by id) as cnt
      from t
     ) t
where cnt < 10

从 table 中删除用户记录很少的行

Delete rows from table with few user records

sql

postgresql

dml