• 2022-06-07
    统计每个部门中的人数的语句是【】。
    A: SELECT SUM(ID) FROM examp GROUP BY DE_NUM
    B: SELECT COUNT(ID) FROM examp ORDER BY DE_NUM
    C: SELECT COUNT(ID) FROM examp GROUP BY DE_NUM
    D: SELECT SUM(ID) FROM examp ORDER BY DE_NUM
  • C

    内容

    • 0

      假定用户表user有多列,其中字段id中没有null值,字段username中存在null值。下面选项中,不能获得user表的总记录数的SQL语句是( ) A: select count(*) from user; B: select count(id) from user; C: select count(username) from user; D: select count(id) from user where1=1;

    • 1

      已知用户表 user 有多列,其中字段 id 没有 NULL 值,字段username有NULL值,选项中,不能获得 user 表的总记录数量的 SQL 语句是 A: SELECT COUNT (*) FROM user ; B: SELECT COUNT ( id ) FROM user ; C: SELECT COUNT ( username ) FROM user ; D: SELECT COUNT ( id ) FROM user WHERE 1=1;

    • 2

      统计各系男生人数,最准确的SQL语句是(<br/>)。 A: SELECT<br/>COUNT(*) FROM stduents GROUP BY d_no WHERE sex='男' B: SELECT<br/>COUNT(*) FROM students WHERE sex='男'<br/>GROUP BY d_no C: SELECT<br/>COUNT(*) FROM students WHERE sex='男'<br/>ORDER BY d_no D: SELECT<br/>COUNT(*) FROM students HAVING sex='男'<br/>GROUP BY d_no

    • 3

      把查询语句的各个子句按执行的先后顺序排列,正确的是( ) A: FROM→WHERE→GROUP BY→SELECT→ORDER BY B: SELECT→FROM→WHERE→GROUP BY→ORDER BY C: WHERE→FROM→SELECT→GROUP BY→ORDER BY D: FROM→WHERE→SELECT→ORDER BY→GROUP BY

    • 4

      按课程号分类,统计相应的选课人数() A: select cid, count(distinct sid) from sc group by cid B: select cid, count(*) from student group by cid C: select cid, count(distinct cid) from sc group by cid D: select cid, count(distinct sid) from student group by cid