神州数码电子通信类笔试题和面试题答案

更新时间:2023-07-14 16:33:26文/高考志愿库

  1)description of the students table:

  sid_id number

  start_date date

  end_date date

  which two function are valid on the start_date column?_________。

  a. sum(start_date)

  b. avg(start_date)

  c. count(start_date)

  d. avg(start_date,end_date)

  e. min(start_date)

  f. maximum(start_date)

  2)which statement shows the maximum salary paid in each job category of each department?_______

  a. select dept_id, job_cat,max(salary) from employees where salary > max(salary);

  b. select dept_id, job_cat,max(salary) from employees group by dept_id,job_cat;

  c. select dept_id, job_cat,max(salary) from employees;

  d. select dept_id, job_cat,max(salary) from employees group by dept_id;

  e. select dept_id, job_cat,max(salary) from employees group by dept_id,job_cat,salary;

  3)for which two constraints does the oracle server implicitly create a unique index?______。

  a. not null

  b. primary

  c. foreign key

  d. check

  e. unique

  4)in a select statement that includes a where clause,where is the group by clause placed in the select statement?______。

  a. immediately after the select clause

  b. before the where clause

  c. before the from clause

  d. after the order by clause

  e. after the where clause

  5)in a select statement that includes a where clause,where is the order by clause placed in the select statement?______.

  a.immediately after the select clause

  b.before the where clause

  c.after all clause

  d.after the where clause

  e.before the from clause

  6)evaluate there two sql statements______.

  select last_name,salary from employees order by salary;

  select last_name,salary from employees order by 2 asc;

  a.the same result b.different result c.the second statement returns a syntax error

  7) you would like to display the system date in the format“20051110 14:44:17”。which select statement should you use?______。

  a. select to_date(sydate,’yearmmdd hh:mm:ss’)from dual;

  b. select to_char(sydate,’yearmonthday hh:mi:ss’)from dual;

  c. select to_date(sydate,’yyyymmdd hh24:mi:ss’)from dual;

  d. select to_char(sydate,’yyyymmdd hh24:mi:ss’)from dual;

  e. select to_char(sydate,’yy-mm-dd hh24:mi:ss’)from dual;

  8)which select statement will the result ‘ello world’from the string‘hello world’?______.

  a. select substr(‘hello world’,1)from dual;

  b. select substr(trim(‘hello world’,1,1))from dual;

  c. select lower(substr(‘hello world’,1))from dual;

  d. select lower(trim(‘h’from‘hello world’))from dual;

  9)which are dml statements(choose all that apply)______.

  a.commit b.merge c.update d.delete e.creat f.drop

  10)select 语句中用来连接字符串的符号是___c___.

  a. “+” b. “&” c.“||” d.“|”

  问答题: 什么是聚集索引,什么是非聚集索引,什么又是主键?

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