数据集团数据库初试笔试题目 资源介绍： 1)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; 2)description of the students table: sid_id number start datedate 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) 3)for which two constraints does the oracle server implicitly create a unique index？_o a.not null b.primary c.foreign key d.check e.unique
数据集团数据库初试笔试题目 资源介绍： 1)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; 2)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) 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;
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一 a.“+”b.“%26amp;”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？
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______. a. “+” b. “%26amp;” 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？