删除重复数据只保存一条--ms sql及oracle实现方法

ms sql方法：

declare @sss table (ID int, Name varchar(10), address varchar(10))

insert into @sss select 1,'小王','重庆'

insert into @sss select 2,'小张','北京'

insert into @sss select 3,'小明','上海'

insert into @sss select 4,'小红','重庆'

insert into @sss select 5,'小李','重庆'

insert into @sss select 6,'小白','北京'

insert into @sss select 7,'小红','上海'

insert into @sss select 8,'小红','重庆'

delete from @sss where id not in(select min(id) from @sss group by name,address)

------------------------------------------------------------------------------------------------------------

oracle方法：

SQL> CREATE TABLE test_delete(

2 name varchar(10),

3 value INT

4 );

表已创建。

SQL> INSERT INTO test_delete

2 SELECT '张三', 100 FROM dual

3 UNION ALL SELECT '张三', 100 FROM dual

4 UNION ALL SELECT '李四', 80 FROM dual

5 UNION ALL SELECT '王五', 80 FROM dual

6 UNION ALL SELECT '王五', 80 FROM dual

7 UNION ALL SELECT '赵六', 90 FROM dual

8 UNION ALL SELECT '赵六', 70 FROM dual;

已创建7行。

SQL> SELECT

2 ROWID,

3 name,

4 value

5 FROM

6 test_delete;

ROWID NAME VALUE

------------------ ---------- ----------

AAAM2mAAGAAAAOXAAA 张三 100

AAAM2mAAGAAAAOXAAB 张三 100

AAAM2mAAGAAAAOXAAC 李四 80

AAAM2mAAGAAAAOXAAD 王五 80

AAAM2mAAGAAAAOXAAE 王五 80

AAAM2mAAGAAAAOXAAF 赵六 90

AAAM2mAAGAAAAOXAAG 赵六 70

已选择7行。

SQL> DELETE test_delete

WHERE (name, value) IN (SELECT name, value FROM test_delete GROUP BY name, value HAVING COUNT(1) > 1)

AND rowid NOT IN (SELECT MIN(rowid) FROM test_delete GROUP BY name, value HAVING COUNT(1) > 1);

已删除2行。

SQL> SELECT

2 ROWID,

3 name,

4 value

5 FROM

6 test_delete;

ROWID NAME VALUE

------------------ ---------- ----------

AAAM2mAAGAAAAOXAAA 张三 100

AAAM2mAAGAAAAOXAAC 李四 80

AAAM2mAAGAAAAOXAAD 王五 80

AAAM2mAAGAAAAOXAAF 赵六 90

AAAM2mAAGAAAAOXAAG 赵六 70