sql面试的
1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断
select * from people
where peopleId in (select peopleId from people group by peopleId having count
(peopleId) > 1)
2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录
delete from people
where peopleId in (select peopleId from people group by peopleId having count
(peopleId) > 1)
and rowid not in (select min(rowid) from people group by peopleId having count(peopleId
)>1)
3、查找表中多余的重复记录（多个字段）
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having
count(*) > 1)
4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录
delete from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having
count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)
5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录
select * from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having
count(*) > 1)
and rowid not in (select min(rowid) from vitae group by peopleId,seq having count(*)>1)
相关文档：
第一种：
SELECT
CASE
WHEN
price IS NULL THEN
'Not yet priced'
WHEN
price < 10 THEN
'Very Reasonable Title'
WHEN
price >= 10 AND
price < 20 THEN
'Coffee Table Title'
EL ......
1. 程序如下：
string str = "Create Database " + "DBname";
string con = "Data Source=10.0.0.249\\sql2005;Initial Catalog=master;Persist Security Info=True;User ID=sa;Password=sa";
&n ......
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient; //引用命名空间
namespace DAL
{
/*******************************************************************************
&n ......
SQL高级使用
SELECT高级查询
错误处理
事务处理
数据的锁定
游标
1.SELECT高级查询
前面已经介绍了SELECT语句的用法，本节主要介绍数据汇总、联接查询、子查询和关键词UNION的使用。
(1)数据汇总
为决策支持系统生成聚合事务的汇总报表是一项复杂并且相当消耗资源的工作。SQL Server 2000提供两个灵活且强大的组件 ......
sql统计－关于学生成绩(答案)
http://blog.sina.com.cn/s/blog_61380b320100ej9p.html
答案：
1. 计算每个人的总成绩并排名
select name,sum(score) as allscore from stuscore group by name order by allscore
2. &nbs ......
