BEGIN
    FOR c IN ( SELECT COLUMN_NAME cn FROM all_tab_columns WHERE table_name = '表名' )
    loop
BEGIN
    execute IMMEDIATE 'alter table 表名 rename column "' || c.cn || '" to ' || c.cn;
EXCEPTION 
    WHEN others THEN
    dbms_output.put_line ( '表名' || '.' || c.cn || '已经存在' );

END;

END loop;
END;