A、 select sex,count(*) from student group by sex
B、 select sex,sum(*) from student group by sex
C、 select sex,sum(sex) from student group by sex
D、 select sex,count(sex) from student order by sex
答案:A
A、 select sex,count(*) from student group by sex
B、 select sex,sum(*) from student group by sex
C、 select sex,sum(sex) from student group by sex
D、 select sex,count(sex) from student order by sex
答案:A
A. Union
B. Substract
C. Map
D. FlatMap
A. 产品经理
B. 客户经理
C. 数据分析师
D. 业务人员
A. def
B. class
C. return
D. function
A. RTRIM(str)
B. LTRIM(str)
C. TRIM(str)
D. 以上都可以
A. 三一二
B. 三二一
C. 一二三
D. 一三二
A. 缓冲层
B. 中间层
C. 应用层
D. 基础层
A. np.prod
B. np.var
C. np.mean
D. np.std