问题
I'm trying to change the inputted domain name to a new domain name, for example, "hotmail.com" becomes "outlook.com". I believe I'm on the right track, just my substring is off.
CREATE OR REPLACE PROCEDURE PR_ChangeDomain
(P_Email_Address varchar2)
IS
Cursor C_Email IS
Select Email_Address, Broker_Number
From Customer
Where Email_Address = P_Email_Address;
V_Email varchar2(50);
BEGIN
Open C_Email;
Fetch C_Email into V_Email;
While C_Email%FOUND LOOP
Update Customer
Set Email_Address = SUBSTR((Email_Address), V_Email)
Where Email_Address = P_Email_Address;
Fetch C_Email into V_Email;
End Loop;
Close C_Email;
End PR_ChangeDomain;
/
回答1:
Code you wrote doesn't make much sense; too much fetching which won't work (two columns into a single variable?).
Here's an example: a test table:
SQL> create table test (email varchar2(30));
Table created.
SQL> insert into test
2 select 'lf@hotmail.com' from dual union all
3 select 'bigfoot@net.hr' from dual union all
4 select 'stack@gmail.com' from dual union all
5 select 'overflow@gmail.com' from dual;
4 rows created.
How to split domain part from it (2nd column of the following SELECT) and update e-mail addresses to a new domain (3rd column):
SQL> select email,
2 substr(email, instr(email, '@') + 1) domain,
3 replace(email,
4 substr(email, instr(email, '@') + 1),
5 'new_domain.com'
6 ) result
7 from test;
EMAIL DOMAIN RESULT
------------------------- --------------- -------------------------
lf@hotmail.com hotmail.com lf@new_domain.com
bigfoot@net.hr net.hr bigfoot@new_domain.com
stack@gmail.com gmail.com stack@new_domain.com
overflow@gmail.com gmail.com overflow@new_domain.com
SQL>
Let's update only Gmail e-mail addresses to a new domain:
SQL> update test set
2 email = replace(email,
3 substr(email, instr(email, '@') + 1),
4 'new_domain.com'
5 )
6 where substr(email, instr(email, '@') + 1) = 'gmail.com';
2 rows updated.
SQL> select * From test;
EMAIL
-------------------------
lf@hotmail.com
bigfoot@net.hr
stack@new_domain.com
overflow@new_domain.com
SQL>
If you want to convert it to a procedure, no problem:
SQL> rollback;
Rollback complete.
SQL> create or replace procedure p_change_domain
2 (par_old_domain in varchar2,
3 par_new_domain in varchar2)
4 is
5 begin
6 update test set
7 email = replace(email,
8 substr(email, instr(email, '@') + 1),
9 par_new_domain
10 )
11 where substr(email, instr(email, '@') + 1) = par_old_domain;
12 end;
13 /
Procedure created.
SQL> exec p_change_domain('gmail.com', 'new_domain_2.com');
PL/SQL procedure successfully completed.
SQL> select * From test;
EMAIL
-------------------------
lf@hotmail.com
bigfoot@net.hr
stack@new_domain_2.com
overflow@new_domain_2.com
SQL>
If you desperately want to use cursors (I don't know why would you want to do that; it'll be probably the most inefficient option), here you go:
SQL> rollback;
Rollback complete.
SQL> create or replace procedure p_change_domain
2 (par_old_domain in varchar2,
3 par_new_domain in varchar2)
4 is
5 begin
6 for cur_r in (select email from test
7 where substr(email, instr(email, '@') + 1) = par_old_domain
8 )
9 loop
10 update test set
11 email = replace(email,
12 substr(email, instr(email, '@') + 1),
13 par_new_domain
14 )
15 where email = cur_r.email;
16 end loop;
17 end;
18 /
Procedure created.
SQL> exec p_change_domain('gmail.com', 'new_domain_3.com');
PL/SQL procedure successfully completed.
SQL> select * From test;
EMAIL
-------------------------
lf@hotmail.com
bigfoot@net.hr
stack@new_domain_3.com
overflow@new_domain_3.com
SQL>
Cursor FOR loop is easier to maintain than your attempt (creating a cursor and a cursor variable, opening the cursor, fetching from it, taking care about exiting the loop, closing the cursor).
But, if you can't live without it, here you go:
SQL> rollback;
Rollback complete.
SQL> create or replace procedure p_change_domain
2 (par_old_domain in varchar2,
3 par_new_domain in varchar2)
4 is
5 cursor c1 is
6 select email from test
7 where substr(email, instr(email, '@') + 1) = par_old_domain;
8 c1r c1%rowtype;
9 begin
10 open c1;
11 loop
12 fetch c1 into c1r;
13 exit when c1%notfound;
14
15 update test set
16 email = replace(email,
17 substr(email, instr(email, '@') + 1),
18 par_new_domain
19 )
20 where email = c1r.email;
21 end loop;
22 close c1;
23 end;
24 /
Procedure created.
SQL> exec p_change_domain('gmail.com', 'new_domain_4.com');
PL/SQL procedure successfully completed.
SQL> select * From test;
EMAIL
-------------------------
lf@hotmail.com
bigfoot@net.hr
stack@new_domain_4.com
overflow@new_domain_4.com
SQL>
My suggestion? Use pure SQL, if possible. Or the first PL/SQL procedure. Don't use cursors for this purpose.
来源：https://stackoverflow.com/questions/52692823/replacing-email-domains