通过一道051的考题看这两个默认参数的用法:
91.View the Exhibit and examine the structure of the PROMOTIONS table. Which two SQL statements would execute successfully?
A.UPDATE promotions SET promo_cost = promo_cost+ 100 WHERE TO_CHAR(promo_end_date, 'yyyy') > '2000';
B.SELECT promo_begin_date FROM promotions WHERE TO_CHAR(promo_begin_date,'mon dd yy')='jul 01 98';
C.UPDATE promotions SET promo_cost = promo_cost+ 100 WHERE promo_end_date > TO_DATE(SUBSTR('01-JAN-2000',8));
D.SELECT TO_CHAR(promo_begin_date,'dd/month') FROM promotions WHERE promo_begin_date IN (TO_DATE('JUN 01 98'), TO_DATE('JUL 01 98'));
答案:AB
A:正确
B:正确
C:错误
D:错误
C和D的错误都是因为没有指定转换的格式,而默认的格式是通过
NLS_DATE_LANGUAGEE和NLS_DATE_FORMAT决定的,因此他们都存在问题,可以进行如下修改
SQL> select TO_DATE(SUBSTR('01-JAN-2000',8)) from dual; select TO_DATE(SUBSTR('01-JAN-2000',8)) from dual ORA-01861: 文字与格式字符串不匹配 SQL> alter session set NLS_DATE_FORMAT='yyyy'; Session altered SQL> select TO_DATE(SUBSTR('01-JAN-2000',8)) from dual; TO_DATE(SUBSTR('01-JAN-2000',8 ------------------------------ 2000/12/1 SQL> select TO_DATE('JUN 01 98') from dual; select TO_DATE('JUN 01 98') from dual ORA-01841: (完整) 年份值必须介于 -4713 和 +9999 之间, 且不为 0 SQL> alter session set NLS_DATE_FORMAT='MON DD RR'; Session altered SQL> alter SESSION SET NLS_DATE_LANGUAGE='AMERICAN'; Session altered SQL> select TO_DATE('JUN 01 98') from dual; TO_DATE('JUN0198') ------------------ 1998/6/1
免责声明:本站发布的内容(图片、视频和文字)以原创、转载和分享为主,文章观点不代表本网站立场,如果涉及侵权请联系站长邮箱:is@yisu.com进行举报,并提供相关证据,一经查实,将立刻删除涉嫌侵权内容。