Question

我有一个包含这些列的表：

tel_number,date,time

单个tel_number可能有多条记录。对于每个tel_number，我想删除除表中最近日期的记录以外的所有记录，并且在最近日期有多个记录的情况下，将选择具有最近时间的记录，并且所有其余记录将被选中应该从表中删除。

例如来自这些记录：

1 2223333,14/01/28,08:30
2 2223333,14/01/27,08:30
3 2223333,14/01/28,16:30
4 2225555,14/01/27,10:34
5 2225555,13/12/29,10:34

除了这两个以外的所有记录都应删除：

3 2223333,14/01/28,16:30
4 2225555,14/01/27,10:34

编辑：

到目前为止，我已尝试过此操作，但它不会删除具有相同日期但时间不同的记录：

delete from table where (tel_number,date) not in 
(select tel_number,max(date) from table group by tel_number);

Answer 1

根据Deleting Duplicate Rows In Oracle：

1。使用 MIN（rowid）：删除重复行的最常用方法。

DELETE FROM Table1
      WHERE ROWID NOT IN (SELECT   MIN (ROWID)
                              FROM Table1
                          GROUP BY tel_number, Date, Time);

2。使用 MIN（rowid）＆amp;加入：或多或少与第一个相同

DELETE FROM Table1 t
      WHERE t.ROWID NOT IN (SELECT MIN (b.ROWID)
                              FROM Table1 b
                             WHERE b.tel_number = t.tel_number
                               AND b.Date = t.Date 
                               AND b.Time = t.Time);

3. 使用分析功能

DELETE FROM Table1 
      WHERE ROWID IN (
               SELECT rid
                 FROM (SELECT ROWID rid,
                              ROW_NUMBER () OVER (PARTITION BY tel_number,Date, Time ORDER BY ROWID) rn
                         FROM Table1 )
                WHERE rn <> 1);

Answer 2

我用这个查询解决了这个问题：

 delete from table a where (a.tel_number,a.DATE,a.TIME) not in 
    (
        select tel_number,date,max(time) 
        from table group by tel_number,date 
        having date in 
        (
            select max(date) from table group by tel_number
        )
    );

从表中删除按两列排序的记录

2 个答案: