数据库面试题.net

1.ADO.net中常用的对象

connection, command, sqladapter, dataset, dataview.

2.net中读写数据库要用到哪些类

DataSet数据存储 DataCommand 执行语句 DataAdapter数据集合

3.写出一条SQL语句取出表A中第31到40的记录
        
select row name from(select row_number() over(order by id)as row,name from A) as AWithRowNumber where row >=31 and row<=40

4什么叫做SQL注入，如何防止？请举例说明。

答：利用sql关键字对网站进行攻击。过滤关键字'等

5：怎么把这样一个表儿
year month amount
1991   1     1.1
1991   2     1.2
1991   3     1.3
1991   4     1.4
1992   1     2.1
1992   2     2.2
1992   3     2.3
1992   4     2.4
查成这样一个结果
year m1 m2 m3 m4
1991 1.1 1.2 1.3 1.4
1992 2.1 2.2 2.3 2.4

答案一、
select year,
(select amount from aaa m where month=1 and m.year=aaa.year) as m1,
(select amount from aaa m where month=2 and m.year=aaa.year) as m2,
(select amount from aaa m where month=3 and m.year=aaa.year) as m3,
(select amount from aaa m where month=4 and m.year=aaa.year) as m4
from aaa group by year

这个是ORACLE 中做的：
select * from (select name, year b1, lead(year) over
(partition by name order by year) b2, lead(m,2) over(partition by name order by year) b3,rank()over(
partition by name order by year) rk from t) where rk=1;