在sql中可以将计算出的平均值作为新的一列插入变中

在sql中可以将计算出的平均值作为新的一列插入变中

不知道你要的是哪一种 看下面代码 应该有你要的
SQL> create table test1(id int,cnt int);

Table created.

SQL> insert into test1 values(1,10);

1 row created.

SQL> insert into test1 values(1,20);

1 row created.

SQL> insert into test1 values(1,30);

1 row created.

SQL> insert into test1 values(2,30);

1 row created.

SQL> insert into test1 values(2,50);

1 row created.

SQL> insert into test1 values(2,60);

1 row created.

SQL> commit;

Commit complete.

SQL> select * from test1;

ID CNT
---------- ----------
1 10
1 20
1 30
2 30
2 50
2 60

6 rows selected.

SQL> insert into test1 select id,avg(cnt) cnt from test1 group by id;

2 rows created.

SQL> commit;

Commit complete.

SQL> select * from test1;

ID CNT
---------- ----------
1 10
1 20
1 30
2 30
2 50
2 60
1 20
2 47

8 rows selected.

SQL> create table test2 as select * from test1;

Table created.

SQL> alter table test2 add (avgcnt int);

Table altered.

SQL> select * from test2;

ID CNT AVGCNT
---------- ---------- ----------
1 10
1 20
1 30
2 30
2 50
2 60
1 20
2 47

8 rows selected.

SQL> update test2 a set avgcnt=(select avg(cnt) from test2 b where a.id=b.id group by id);

8 rows updated.

SQL> commit;

Commit complete.

SQL> select * from test2;

ID CNT AVGCNT
---------- ---------- ----------
1 10 20
1 20 20
1 30 20
2 30 47
2 50 47
2 60 47
1 20 20
2 47 47

8 rows selected.

SQL>

首先往表里追加一列。 update XXXX set avg_col=avg(c1,c2,.......,cn)

通过子查询，或者自定义函数来实现就行