【单选题】假定student表及对应字段都存在,阅读下面SQL代码: DECLARE s_grade FLOAT; DECLARE s_gender CHAR(2); SELECT grade, gender INTO s_grade, s_gender FROM student WHERE name = 'rose'; 关于上述代码的描述中,正确的是
【单选题】关于下面代码,描述错误的是: from collections import Iterable from collections import Iterator r = range(10) print(isinstance(r, Iterable)) print(isinstance(r, Iterator)) l = list(r) print(l) t = tuple(r) print(t)