‎If A and B are m × n matrices then have the same rank, then the rank of AB must equal the rank of BA.‌‎‌

a是一个数组变量，以下（ ）返回数组的元素个数。 A: a.Rank B: a.Long C: a.Count D: a.Length

以下语句错误的是() A: LECT rank, AVG(salary) FROM people HAVING AVG(salary) > 1000 GROUP BY rank; B: SELECT rank, AVG(salary) FROM people GROUP BY rank HAVING AVG(salary) > 1000 C: SELECT rank, AVG(salary) FROM people HAVING AVG(salary) > 1000 GROUP BY rank; D: SELECT AVG(salary) FROM people GROUP BY rank HAVING AVG(salary) > 1000; E: SELECT rank, AVG(salary) FROM people GROUP BY rank WHERE AVG(salary) > 1000;

Let A be an m×n matrix, then ( ). A: AAT =ATA. B: if rank(A) = m, then AT A is invertible. C: if rank(A) = n, then AAT is invertible. D: if rank(A) = n, then AT A is invertible.

The lowest naval officer rank is ______ , while the lowest army officer rank is ______ .(全部小写)

rank函数最常用的是求某一个数值在某一区域内的排名。rank函数语法形式:rank(number,ref,[order])，ref表示（

如果要获得一维数组A中元素的个数，则不能使用( )。 A: A.Length B: A.Rank C: A.GetLength(0) D: A.longLength

在ORACLE中，rank()函数和dense_rank()函数的差别是（选一项） A: rank函数和dense_rank函数都没有跳跃 B: rank函数和dense_rank函数都有跳跃 C: rank函数有跳跃 dense_rank函数没有跳跃 D: rank函数没有跳跃 dense_rank函数有跳跃

This is important to know because the person of lesser rank or authority should always be introduced to the person of higher rank or authority.

In the rank sum test of ordinal variables, the average rank of each category is the lower bound of the corresponding range of rank.