（102）Examine the structure of the TRANSACTIONS table:

name Null Type

TRANS_ID NOT NULL NUMBER(3)

CUST_NAME VARCHAR2(30)

TRANS_DATE TIMESTAMP

TRANS_AMT NUMBER(10,2)

You want to display the date, time, and transaction amount of transactions that where done before 12 noon.

The value zero should be displayed for transactions where the transaction amount has not been entered.

Which query gives the required result?

A.

SELECT TO_CHAR(trans_date,'dd-mon-yyyy hh24:mi:ss'), TO_CHAR(trans_amt,'$99999999D99')

FROM transactions

WHERE TO_NUMBER(TO_DATE(trans_date,'hh24')) < 12 AND COALESCE(trans_amt, NULL)<>NULL;

B.

SELECT TO_CHAR(trans_date,'dd-mon-yyyy hh24:mi:ss'), NVL(TO_CHAR(trans_amt,'$99999999D99'),0)

FROM transactions

WHERE TO_CHAR(trans_date,'hh24') < 12;

C.

SELECT TO_CHAR(trans_date,'dd-mon-yyyy hh24:mi:ss'), COALESCE(TO_NUMBER(trans_amt,'$99999999.99'),0)

FROM transactions

WHERE TO_DATE(trans_date,'hh24') < 12;

D.

SELECT TO_DATE (trans_date,'dd-mon-yyyy hh24:mi:ss'), NVL2(trans_amt,TO_NUMBER(trans_amt,'$99999999.99'), 0)

FROM transactions

WHERE TO_DATE(trans_date,'hh24') < 12;

答案：（B）

解析：

A（X），<>NULL就错了

C（X），D（X），不应该调用TO_NUMBER()函数

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OCP 1Z0-051-102