PL/SQL 程序块

DECLARE BARCODE VARCHAR(50);BEGIN  BARCODE := 'A';  IF BARCODE<>'A' then    SELECT 1 FROM sam_users;  ELSE    SELECT 2 FROM sam_users;  END IF;END;DECLARE ENAME VARCHAR(50);BEGIN  ENAME := 'SMITH';  IF ENAME<>'A' then    SELECT 1 Into ENAME  FROM dual;    DBMS_OUTPUT.PUT_LINE(ENAME);  ELSE    SELECT 2 Into ENAME FROM dual;     DBMS_OUTPUT.PUT_LINE(ENAME);  END IF;END;DECLARE ENAME VARCHAR(50);BEGIN  ENAME := 'SMITH';  IF ENAME<>'A' then    execute immediate 'SELECT 1   FROM dual';  ELSE      execute immediate 'SELECT 2  FROM dual';  END IF;END;