What is wrong with this PL/SQL? Bind Variable * is NOT DECLARED

Question

Here is:

declare
  v_str1   varchar2(80);
begin
  v_str1 := \'test\';
  print :v_str1;
end

When I run it using SQLDeveloper just in a sql w

Answer 1

Try

declare
  v_str1   varchar2(80);
begin
  v_str1 := 'test';
  print v_str1;
end

Answer 2

Got it:

set serveroutput on

declare
  v_str1   varchar2(80);    
begin
 v_str1 := 'test';
 dbms_output.put_line(v_str1);
end;

More info here.

Answer 3

The bind variables syntax of the form :VARNAME are used primarily in SQL* Plus (except for bind variables for dynamic SQL, I think). For SQL* Developer, PL/SQL Developer, or other apps, there is the "&" for variable substitution:

declare
  v_str1   varchar2(80);
begin
  v_str1 := &v_str;
  print v_str1;
end

EDIT: My bad, the code for Oracle SQL*Developer should have been:

set serveroutput on;
declare
  v_str1   varchar2(80);
begin
  v_str1 := '&v_str';
  dbms_output.put_line(v_str1);
end;

You have to select everything and execute it. The result will appear in the "Script Output" panel.

Answer 4

print is not a PLSQL function. If you want to get an output, you can use dbms_output.put_line(v_str1);

set serveroutput on;    
declare v_str1 varchar2(80);
begin
    v_str1 := 'test'; 
    dbms_output.put_line(v_str1);
end;

:v_str1 is a bind variable but you must declare not in a plsql. When you declare it you must use VARIABLE keyword.