OCP-1Z0-051-V9.02-14题

14. Using the CUSTOMERS table, you need to generate a report that shows 50% of each credit

amount in each income level. The report should NOT show any repeated credit amounts in each income

level. --each income level中没有重复的credit amounts

Which query would give the required result?

A.

SELECT cust_income_level, DISTINCT cust_credit_limit * 0.50

AS "50% Credit Limit"

FROM customers;

[sql] view
plaincopyprint?

sh@TESTDB> SELECT cust_income_level, DISTINCT cust_credit_limit * 0.50

2 AS "50% Credit Limit"

3 FROM customers;

SELECT cust_income_level, DISTINCT cust_credit_limit * 0.50

*

ERROR at line 1:

ORA-00936: missing expression

语法错误，DISTINCT不应该放在第二列，应该放在第一列中

[sql] view
plaincopyprint?

sh@TESTDB> SELECT DISTINCT cust_income_level,cust_credit_limit * 0.50

2 AS "50% Credit Limit"

3 FROM customers where rownum<6;

CUST_INCOME_LEVEL 50% Credit Limit

------------------------------ ----------------

G: 130,000 - 149,999 5500

G: 130,000 - 149,999 4500

G: 130,000 - 149,999 3500

G: 130,000 - 149,999 750

B.

SELECT DISTINCT cust_income_level, DISTINCT cust_credit_limit * 0.50

AS "50% Credit Limit"

FROM customers;

同A，语法错误，DISTINCT不应该放在第二个

[sql] view
plaincopyprint?

SELECT DISTINCT cust_income_level, DISTINCT cust_credit_limit * 0.50

2 AS "50% Credit Limit"

3 FROM customers;

SELECT DISTINCT cust_income_level, DISTINCT cust_credit_limit * 0.50

*

ERROR at line 1:

ORA-00936: missing expression

C.

SELECT DISTINCT cust_income_level ' ' cust_credit_limit * 0.50

AS "50% Credit Limit"

FROM customers;

[sql] view
plaincopyprint?

sh@TESTDB> SELECT DISTINCT cust_income_level ' ' cust_credit_limit * 0.50

2 AS "50% Credit Limit"

3 FROM customers;

SELECT DISTINCT cust_income_level ' ' cust_credit_limit * 0.50

*

ERROR at line 1:

ORA-00923: FROM keyword not found where expected

这道题愿意为用' '连接两个列，可能用错，应为||来连接，不过DISTINCT的位置 对的

[sql] view
plaincopyprint?

sh@TESTDB> SELECT DISTINCT cust_income_level || cust_credit_limit * 0.50

2 AS "50% Credit Limit"

3 FROM customers where rownum<6;

50% Credit Limit

----------------------------------------------------------------------

G: 130,000 - 149,999750

G: 130,000 - 149,9994500

G: 130,000 - 149,9993500

G: 130,000 - 149,9995500

D.

SELECT cust_income_level ' ' cust_credit_limit * 0.50 AS "50% Credit Limit"

FROM customers

D没有满足NOT show any repeated的条件。

此题答案C