Create procedure with if in oracle sql - oracle

Question

I need to create a procedure that search an email in a table, and if it doesn´t exists the procedure creates a new record with this email.
Something like this:
CREATE PROCEDURE check_email (in #email varchar2(99)) AS
BEGIN
IF SELECT email FROM user u WHERE u.email:=email
dbms_output.put_line('This email exists');
ELSE
BEGIN
INSERT INTO user (id, name, surname, city, address, age, email) VALUES (id_user.nextval,'David','Alcatraz','Sevilla', 'Avd miguel de unamuno', 23, email || '#gmail.com')
END

Answer 1

Take this in consideration:
A variable to store the counter of email from the table.
You must close each statement with semicolon.
An input variable is defined with its type without length.
It would look like
CREATE PROCEDURE check_email (p_email in varchar2 ) AS
v_counter pls_integer;
BEGIN
SELECT count(*) into v_counter FROM user WHERE upper(email) = upper(p_email);
if v_counter = 1
then
dbms_output.put_line('This email exists');
ELSE
INSERT INTO user (id, name, surname, city, address, age, email) VALUES
(id_user.nextval,'David','Alcatraz','Sevilla', 'Avd miguel de unamuno', 23, p_email ||
'#gmail.com');
commit;
END IF;
exception when others then raise;
END;

Answer 2

Why bother? Let the database handle that.
Here's how: as e-mail addresses have to be unique, create a unique key constraint on that column:
SQL> create table t_user
2 (id number constraint pk_user primary key,
3 name varchar2(20) not null,
4 e_mail varchar2(30) not null,
5 --
6 constraint uk_user_mail unique (e_mail)
7 );
Table created.
Sequence will be used for the ID column values.
SQL> create sequence tseq;
Sequence created.
Procedure: if there's unique key violation, simply don't do anything. Other errors, if any, will be automatically raised by Oracle. You can handle them, if you want.
SQL> create or replace procedure p_user
2 (par_name in t_user.name%type,
3 par_email in t_user.e_mail%type)
4 is
5 begin
6 insert into t_user (id, name, e_mail)
7 values (tseq.nextval, par_name, par_email);
8 exception
9 when dup_val_on_index then null;
10 end;
11 /
Procedure created.
Testing:
SQL> exec p_user('Little', 'lf#mail.com');
PL/SQL procedure successfully completed.
SQL> exec p_user('Foot' , 'lf#mail.com');
PL/SQL procedure successfully completed.
SQL> exec p_user('Victor', 'victor#mail.com');
PL/SQL procedure successfully completed.
SQL> select * From t_user;
ID NAME E_MAIL
---------- -------------------- ------------------------------
1 Little lf#mail.com
3 Victor victor#mail.com
SQL>
As you can see, Foot never entered the table as its e-mail address already exists in the table.