ORACLE中动态SQL语句过长

CREATE OR REPLACE PROCEDURE demo(REF_A  OUT sys_refcursor)
 AS
 s_sql varchar2(50);
BEGIN
  s_sql:=‘select sysdate from dual‘;--初始化动态sql
  open REF_A for s_sql; ---返回游标
END;

CREATE OR REPLACE PROCEDURE demo(REF_A  OUT sys_refcursor)
 AS
  s_sql clob;--将动态sq语句定义为clob类型
BEGIN
  s_sql:=‘select sysdate from dual‘;--初始化动态sql
  open REF_A for to_char(s_sql); ---将sql转为字符串后执行,返回游标
END;