-- Create table
create table HKB_TEST3
(
USER_ID NUMBER(4),
AGE NUMBER(4),
USER_NUMBER NUMBER(4)
)
SQL> select * from hkb_test3;
USER_ID AGE USER_NUMBER
------- ----- -----------
1 12
2 14
3 16
4 11
例子：
update hkb_test3
set user_number = (select b.user_number
from (select a.user_id,
case
when a.age = 12 then
'6'
when a.age = 14 then
'7'
when a.age = 16 then
'8'
else
'9'
end user_number
from hkb_test3 a) b
where b.user_id = hkb_test3.user_id);
SQL> commit;
Commit complete
SQL> select * from hkb_test3;
USER_ID AGE USER_NUMBER
------- ----- -----------
1 12 6
2 14 7
3 16 9
4 11 9
