Oracle中case语句

-- 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