Oracle資料庫隨機取某條記錄的一個欄位值

思路：

先將取出的值隨機排序，然後在隨機排序的每次取第一條的結果

舉例如下：

select * from(select t.code fromTBIZOPS_PROVINCE  t ORDER BY DBMS_RANDOM.RANDOM())where rownum < 2;
select * from (select t.code from TBIZOPS_CITY t wheret.province_id = '13' ORDER BY DBMS_RANDOM.RANDOM()) where rownum< 2 ;
select * from (select t.code from TBIZOPS_County t wheret.province_id = '13' and t.city_id = '1304'ORDER BYDBMS_RANDOM.RANDOM()) where rownum < 2 ;