8.1.5
没发现有什么问题,仔细检查一下吧15:42:02 SQL> select * from s; SNO SN SE AGE
--------- ---------- -- ---------
1 xm001 m 11
2 xm002 f 12
3 xm003 f 13
4实际:70
15:42:08 SQL> select * from s where sn is null; SNO SN SE AGE
--------- ---------- -- ---------
4实际:100
15:42:23 SQL> update s set sn='xm004' where sn is null;已更新 1 行。实际:240
15:42:56 SQL> select * from s; SNO SN SE AGE
--------- ---------- -- ---------
1 xm001 m 11
2 xm002 f 12
3 xm003 f 13
4 xm004实际:70
15:43:18 SQL> select * from s where sex is null and age is null; SNO SN SE AGE
--------- ---------- -- ---------
4 xm004实际:50
15:43:28 SQL>
没发现有什么问题,仔细检查一下吧15:42:02 SQL> select * from s; SNO SN SE AGE
--------- ---------- -- ---------
1 xm001 m 11
2 xm002 f 12
3 xm003 f 13
4实际:70
15:42:08 SQL> select * from s where sn is null; SNO SN SE AGE
--------- ---------- -- ---------
4实际:100
15:42:23 SQL> update s set sn='xm004' where sn is null;已更新 1 行。实际:240
15:42:56 SQL> select * from s; SNO SN SE AGE
--------- ---------- -- ---------
1 xm001 m 11
2 xm002 f 12
3 xm003 f 13
4 xm004实际:70
15:43:18 SQL> select * from s where sex is null and age is null; SNO SN SE AGE
--------- ---------- -- ---------
4 xm004实际:50
15:43:28 SQL>
谢谢各位。给分