Question

in postresql function we can list table by FOR i IN (SELECT …)

CREATE OR REPLACE FUNCTION f()
  RETURNS trigger AS
$BODY$
DECLARE
table_to_row RECORD;
BEGIN
<<for_loop>>
FOR table_to_row IN SELECT id FROM table1
LOOP
    //do something
END LOOP for_loop;
RETURN NULL;
END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;

How can we do such thing in Oracle 11g?
I need this part

FOR table_to_row IN SELECT id FROM table1
LOOP
   //do something
END LOOP;

Answer 1

In Oracle you do not have to explicitly declare a cursor loop variable. It implicitly will be of table_name%rowtype data type.

Here is an example:

For i in (select col_1, .., col_n
            from your_table)
loop
  -- do something
end loop;

Demonstration:

create table test_1(col1 varchar2(11));

Table created

SQL> insert into test_1(col1) values('data_1');

1 row inserted

SQL> insert into test_1(col1) values('data_2');

1 row inserted

SQL> insert into test_1(col1) values('data_3');

1 row inserted

SQL> commit;

Commit complete

SQL> set serveroutput on;

SQL>begin
  2    for i in (select col1 from test_1)
  3    loop
  4      dbms_output.put_line(i.col1);
  5    end loop;
  6  end;
  7  /

data_1
data_2
data_3

PL/SQL procedure successfully completed