How to create a stand alone plpgsql proc

Dear Sir:
  In Oracle, I can create a stand-alone procedure like that:
    DECLARE
      A NUMBER;
      B NUMBER;
    BEGIN
      A := 1;
      B := 2;
      INSERT INTO TABLE1 VALUES (A, B);
    END;
    /
  Then I run it(a.sql) with the command in shell:
    sqlplus username/passwd @a.sql
  In postgresql, how do I write similar plpgsql procedure without
  using "CREATE FUNCTION" or "CREATE PROCEDURE" ..., and how to
  execute it?
                         Thank you
==================================================================
新浪網．免費 50MB 電子信箱  http://www.sinamail.com