仅当计数大于3时，才从表中删除重复记录

Question

我有一张表格如下：

A | B | C

1 | 2 | 3

1 | 2 | 3

1 | 2 | 3

1 | 2 | 3

1 | 2 | 3

4 | 5 | 6

4 | 5 | 6

4 | 5 | 6

4 | 5 | 6

7 | 8 | 9

7 | 8 | 9

7 | 8 | 9

我想删除重复内容，只保留一个值超过3次的记录值。应该是这样的：

A | B | C

1 | 2 | 3

4 | 5 | 6

7 | 8 | 9

7 | 8 | 9

7 | 8 | 9

我有以下代码：

DELETE FROM test5 X
WHERE x.ROWID > ANY
  (SELECT Y.ROWID
    FROM test5 Y
    WHERE
      X.A = Y.A
     AND
      X.B = Y.B
    AND
      X.C = Y.C
    ); 

如何只保留前两个元组（123和456）的一个副本并保留第三元组的所有副本？

Answer 1

如果我清楚地理解您的问题，为什么不使用子查询将删除限制为具有所需值的行。像这样：

null

这应该只删除前两个元组的重复项。

Answer 2

以下语句删除表中发生三次以上的所有行（最旧的行除外）。

delete test5 where rowid in (
  with data as(
  select a,b,c, min(rowid) keep_rowid
  from test5 
  group by a,b,c
  having count(*) > 3)
  select t.rowid from test5 t, data d
  where t.a = d.a
  and t.b = d.b
  and t.c = d.c
  and t.rowid <> d.keep_rowid);

Answer 3

你可以试试这个：

delete test5
 where rowid not in (select rowss
                       from (select A, count(*) counts, min(rowid) rowss
                               from test5
                              group by A
                             having count(*) > 3))--keep one row which's count bigger then 3 (like 1|2|3,4|5|6)
   and A not in(select A from test5 group by A having count(*) <= 3)--keep rows which's counts smaller and equal then 3 (like 7|8|9)

表和列名称应该是抱歉的。