在sqlplus互動環境下測試儲存過程

sqlplus手冊中說得比較清楚

Use the following commands to create and display bind variables.
PRI[NT] [variable ...]
Displays the current values of bind variables, or lists all bind variables.
VAR[IABLE] [variable {NUMBER | CHAR | CHAR (n [CHAR | BYTE]) | NCHAR
| NCHAR (n) | VARCHAR2 (n [CHAR | BYTE]) | NVARCHAR2(n) | CLOB | NCLOB |
REFCURSOR | BINARY_FLOAT | BINARY_DOUBLE}]
Declares a bind variable that can be referenced in PL/SQL, or lists the
current display characteristics for a single variable or all variables.

SQL> create or replace procedure p_test(b_mem_id in char,b_return out number)
  2  is
  3  test number;
  4  begin
  5  b_return:=3;
  6  end;
  7  /

Procedure created.
SQL> var n_return number

SQL>  exec p_test('dfasfd',:n_return);

PL/SQL procedure successfully completed.
SQL> print n_return

  N_RETURN
----------
         3