VARIABLE SCOPE,BIND VARIABLES.SQL

------------------------VARIABLE SCOPE--------------------------
begin <<outer>>
DECLARE
  --v_outer VARCHAR2(50) := 'Outer Variable!';
  v_text  VARCHAR2(20) := 'Out-text';
BEGIN 
  DECLARE
    v_text  VARCHAR2(20) := 'In-text';
    v_inner VARCHAR2(30) := 'Inner Variable';
  BEGIN
    --dbms_output.put_line('inside -> ' || v_outer);
    --dbms_output.put_line('inside -> ' || v_inner);
      dbms_output.put_line('inner -> ' || v_text);
      dbms_output.put_line('outer -> ' || outer.v_text);
  END;
  --dbms_output.put_line('inside -> ' || v_inner);
  --dbms_output.put_line(v_outer);
  dbms_output.put_line(v_text);
END;
END outer;
----------------------------------------------------------------
--------------------------BIND VARIABLES--------------------------
set serveroutput on;
set autoprint on;
/
variable var_text varchar2(30);
/
variable var_number NUMBER;
/
variable var_date DATE;
/
declare
v_text varchar2(30);
begin
:var_text := 'Hello SQL';
:var_number := 20;
v_text := :var_text;
--dbms_output.put_line(v_text);
--dbms_output.put_line(:var_text);
end;
/
print var_text;
/
variable var_sql number;
/
begin 
  :var_sql := 100;
end;
/
select * from employees where employee_id = :var_sql;
/*------------------------BIND VARIABLES--------------------------
NOTE: When you run a bind variable creation and SELECT statement 
together, SQL Developer may return an error but when you execute 
them separately, there will be no problem.
----------------------------------------------------------------*/