-- 'u', 'U' - 返回全是大寫的字串

-- 'l', 'L' - 返回全是小寫的字串

-- 'a', 'A' - 返回大小寫結合的字串

-- 'x', 'X' - 返回全是大寫和數字的字串

-- 'p', 'P' - 返回鍵盤上出現字元的隨機組合

create table test_table as    
SELECT rownum as col_1,
       DBMS_RANDOM.string('~', 5) as col_2,
       DBMS_RANDOM.string('L', 5) as col_3,
       DBMS_RANDOM.string('A', 5) as col_4,
       DBMS_RANDOM.string('U', 5) as col_5,
       DBMS_RANDOM.string('X', 5) as col_6,
       DBMS_RANDOM.string('P', 5) as col_7
  from (SELECT level, ROWNUM rn FROM DUAL CONNECT BY ROWNUM <= 123456)