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047-070

原创 Linux操作系统 作者:jbymy2000 时间:2012-03-18 10:17:08 0 删除 编辑
70. Which two statements are true about the GROUPING function? (Choose two.)
A. It is used to find the groups forming the subtotal in a row.
B. It is used to identify the NULL value in the aggregate functions.
C. It is used to form. the group sets involved in generating the totals and
subtotals.
D. It can only be used with ROLLUP and CUBE operators specified in the GROUP
BY clause.
Answer: AD
The GROUPING function identifies superaggregate or aggregate rows
produced by a ROLLUP or CUBE operation in a SELECT . . . GROUP BY statement.
It returns a value of the NUMBER datatype, and its value is either a one (1)
or a zero (0).The GROUPING function is only valid in a SELECT statement that
uses a GROUP BY clause. While GROUPING may be used in a GROUP BY that doesn’t
include the ROLLUP or CUBE operation, it doesn’t produce anything meaningful
without those operators—it will always return a zero if ROLLUP and CUBE are
absent from the statement.

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