ocp 11g考试题库详解：1Z0-051-101题

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ocp 11g考试题库详解：1Z0-051-101题，完整题库请点击这里联系老师咨询了解

101. Examine the data in the PROMO_BEGIN_DATE column of the PROMOTIONS table:

PROMO_BEGIN _DATE

04-jan-00

10-jan-00

15-dec-99

18-oct-98

22-aug-99

You want to display the number of promotions started in 1999 and 2000.

Which query gives the correct output?

A. SELECT SUM(DECODE(SUBSTR(promo_begin_date,8),'00',1,0)) "2000",

SUM(DECODE(SUBSTR(promo_begin_date,8),'99',1,0)) "1999"

FROM promotions;

B. SELECT SUM(CASE TO_CHAR(promo_begin_date,'yyyy') WHEN '99' THEN 1

ELSE 0 END) "1999",SUM(CASE TO_CHAR(promo_begin_date,'yyyy') WHEN '00' THEN 1

ELSE 0 END) "2000"

FROM promotions;

C. SELECT COUNT(CASE TO_CHAR(promo_begin_date,'yyyy') WHEN '99' THEN 1

ELSE 0 END) "1999",COUNT(CASE TO_CHAR(promo_begin_date,'yyyy') WHEN '00' THEN 1

ELSE 0 END) "2000"

FROM promotions;

D. SELECT COUNT(DECODE(SUBSTR(TO_CHAR(promo_begin_date,'yyyy'), 8), '1999', 1, 0)) "1999",

COUNT(DECODE(SUBSTR(TO_CHAR(promo_begin_date,'yyyy'), 8),'2000', 1,

0)) "2000"

FROM promotions;

Answer: A

试题解析：

分析A答案

SUBSTR(promo_begin_date,8)，即是取日期的最后两个值。

(DECODE(SUBSTR(promo_begin_date,8),'00',1,0)如果最后两个值是00，则值为1，否则为0

(DECODE(SUBSTR(promo_begin_date,8),'99',1,0)如果最后两个值是99，则值为1，否则为0

SUM(DECODE(SUBSTR(promo_begin_date,8),'00',1,0)) 加起来有多少个1，即有多少个2000年的

SUM(DECODE(SUBSTR(promo_begin_date,8),'99',1,0))加起来有多少个1，即有多少个1999年的

B，条件不对，应该 TO_CHAR(promo_begin_date,'yyyy') 改成 TO_CHAR(promo_begin_date,'yy')

C,与B同样错误

D,截取不对，SUBSTR(TO_CHAR(promo_begin_date,'yyyy'), 8)改成SUBSTR(TO_CHAR(promo_begin_date,'yyyy'), 1)