Retrieving the data from the table using the PL/SQL

问题

I want to retrieve all the information about each department from the DEPARTMENT table and display the information on the screen.

Column name      Data type     Constraints

DEPARTMENT_ID    NUMBER(5)     PK

DEPARTMENT_NAME  VARCHAR2(25)  NOT NULL

LOCATION_ID      VARCHAR2(15)

Sample Output:

Department Details are :
1000, ADMIN, HQ-101

1010, DEVELOPMENT, CBE-103

1020, TESTING, CHN-102

I have a code which is as follows-

set serveroutput on;
declare
v_dno department.department_id%type;
v_dname department.department_name%type;
v_loc department.location_id%type;
begin
dbms_output.put_line('Department Details are :');
loop
dbms_output.put_line(v_dno || ', ' || v_dname || ', ' || v_loc);
end loop;
commit;
end;
/

But this isn't producing any output, please help. Thanks in advance!

回答1:

Yes, a simple way to do that is to use a loop. But, you're looping through nothing (never fetch anything into those variables) and never exit the loop. Besides, what exactly are you committing?

Here's how you might have done it (based on Scott's DEPT table which is similar to yours):

SQL> set serveroutput on
SQL> begin
  2    for cur_r in (select deptno, dname, loc from dept) loop
  3      dbms_output.put_line(cur_r.deptno ||' '|| cur_r.dname ||' '|| cur_r.loc);
  4    end loop;
  5  end;
  6  /
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON

PL/SQL procedure successfully completed.

SQL>

来源：https://stackoverflow.com/questions/64451246/retrieving-the-data-from-the-table-using-the-pl-sql