begin
rollback transaction
end
else
begin
commit transaction
end
2隐式事务
3自动提交事务
单独的SQL语句视为一个事务，如果执行自动提交，否则会滚
------------------------------------------
索引
1：主键索引
唯一性 它允许快速访问数据库----定义一个主键将自动创建一个主键索引
2：聚集索引
按 a b c
3：非聚集索引--一个表只能创建一个聚集索引，但能有多个非聚集索引
比聚集索引查询慢
use stuDB--创建索引
go
if exists(select * from sysindexes where name='IX_stuMarks_writtenExam')
drop index IX_stuMarks_writtenExam
create [unique][clustered][noncluster] IX_stuMarks_writtenExam--cluster[klQstE]成群
on stuMarks(writtenExam)
go
查询
select * from stuMarks
(index=IX_stuMarks_writtenExam)
where writtenExam betwenn 60 and 90
---------------------------------------------
视图
if exists(select * from sysobjects where name='view_stuInfo_stuMarks')
drop view view_stuInfo_stuMarks
create view view_stuInfo_stuMarks
as
select ```````.....
go
select * from view_stuInfo_stuMarks
〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓
⑧存储过程
create proc sp_
@tmp varchar()
as
declare @tmp1
1.ASC表示升序排序，DESC表示降序排序
2.quotename print quotename('aabb','''')
把字符加上[]，还可以quotename('aabb','''')把[]变成''加引号
3.创建变量表，多行插入
declare @tmp table(id int primary key ,col decimal(10,2))
insert @tem select 1,25.21
union all select 2,26,23
3.表的复制语法
insert table1 from table2
insert table select.....
select * into table1 from table2
4.cross join
叫查表 两表交叉相乘
5.exec (string)执行拼出来的sql语句
6.创建临时表 只有临时表才能exec（）
create table #tmp()
7.union all union
9.DECLARE CURSOR 游标定义
10. distinct
==================================================
declare @sqlstr varchar(2000)
declare @i int
set @i=2
create table #tmp(tyear int,capital1 money,capital2 money,capital3 money,tdate datetime,tmonth int)
set @sqlstr ='insert #tmp select 2009,1,2,3,'+quotename('2009-12-12','''')+','+convert(varchar(10),1)
while @i<=12
begin
set @sqlstr=@sqlstr+' union all select 2009,1,2,3,'+quotename('2009-12-12','''')+','+convert(varchar(10),@i)
set @i=@i+1
end
print @sqlstr
exec(@sqlstr)
select * from #tmp
select student.stuid,t.* into teacher from student cross join #tmp as t
/**
insert @tmp select 2009,1,2,3,'2009-12-12',1
union all select 2009,1,2,3,'2009-12-12',2
union all select 2009,1,2,3,'2009-12-12',3
union all select 2009,1,2,3,'2009-12-12',4
union all select 2009,1,2,3,'2009-12-12',5
union all select 2009,1,2,3,'2009-12-12',6
union all select 2009,1,2,3,'2009-12-12',7
union all select 2009,1,2,3,'2009-12-12',8
union all select 2009,1,2,3,'2009-12-12',9
union all select 2009,1,2,3,'2009-12-12',10
union all select 2009,1,2,3,'2009-12-12',11
union all select 2009,1,2,3,'2009-12-12',12
drop table teacher
*/
//题目二
select s.stunum,sum(case when tmonth=1 then capital3 else 0 end) '一月',
sum(case when tmonth=2 then capital3 else 0 end) '二月',
sum(case when tmonth=3 then capital3 else 0 end) '三月',
sum(case when tmonth=4 then capital3 else 0 end) '四月',
sum(case when tmonth=5 then capital3 else 0 end) '五月',
sum(case when tmonth=6 then capital3 else 0 end) '六月',
sum(case when tmonth=7 then capital3 else 0 end) '七月',
sum(case when tmonth=8 then capital3 else 0 end)'八月',
sum(case when tmonth=9 then capital3 else 0 end) '九月',
sum(case when tmonth=10 then capital3 else 0 end) '十月',
sum(case when tmonth=11 then capital3 else 0 end) '十一月',
sum(case when tmonth=12 then capital3 else 0 end) '十二月'
from student as s inner join teacher as t on(s.stuid=t.stuid) group by stunum
/**
create table gb
(
gid int identity(1,1) primary key not null,
gname varchar(20) not null
)
insert gb select 'zzk'
union all select 'zzk'
union all select 'zz'
union all select 'zk'
union all select 'k'
union all select 'z'
select * from gb
select count(gname) from gb group by gname having count(gname)>1
select count(gname) from gb
drop table gb
*/
===============================================================================
select itemName from dbo.table1 union all select * from tests
create table a
(
id int null,
names varchar(10),
)
insert into a select 1,'qwe'
union all select 1,'qwe'
union all select 2,'qwe'
union all select 3,'qweasdaa'
drop from a
select * from a
delete from a
//=============
select * from T1
////======列模块
declare @s nvarchar(4000)
set @s=''
Select @s=@s+','+[column2]+'=max(case when [column2]='+quotename([column2],'''')+' then [value] else 0 end)'
from t1 group by[column2]
print @s
/**,电话=max(case when [column2]='电话' then [value] else 0 end),宽带=max(case when [column2]='宽带' then [value] else 0 end) -->*/
exec('select [column1] as 地名'+@s+' from t1 group by [column1]')
//总费用 sum要比group后执行
declare @s nvarchar(4000)
set @s=''
Select @s=@s+','+quotename([column2])+'=max(case when [column2]='+quotename([column2],'''')+' then [value] else 0 end)'
from t1 group by[column2]
exec('select [column1] as 地名'+@s+',[总费用]=sum([value]) from t1 group by [column1]')
//新建零时表 插入行模版
declare @s nvarchar(4000)
declare @tems nvarchar(2000)
set @s=''
Select @s=@s+','+quotename([column2])+'=max(case when [column2]='+quotename([column2],'''')+' then [value] else 0 end)'
from t1 group by[column2]
set @tems='select [column1] as 地名'+@s+',[总费用]=sum([value]) into t2 from t1 group by [column1]'
print @tems
exec('select [column1] as 地名'+@s+',[总费用]=sum([value]) into t2 from t1 group by [column1]')
select * from t2
drop table T2
declare @s1 int ;
declare @s2 int ;
select @s1=sum(isnull(电话,0)),@s2=sum(isnull(宽带,0)) from t2 group by 电话,宽带
print @s1
print @s2
insert into t2(t2.电话,t2.宽带) values(@s1,@s2)
select * from t2
=========================================================================
use MyWeight
select * from #tmp
create table #tmp(rq varchar(10),shengfu nchar(1))
insert into #tmp values('2005-05-09','胜')
insert into #tmp values('2005-05-09','胜')
insert into #tmp values('2005-05-09','负')
insert into #tmp values('2005-05-09','负')
insert into #tmp values('2005-05-10','胜')
insert into #tmp values('2005-05-10','负')
insert into #tmp values('2005-05-10','负')
1)select rq, sum(case when shengfu='胜' then 1 else 0 end)'胜',sum(case when shengfu='负' then 1 else 0 end)'负' from #tmp group by rq
select rq,sum(case when shengfu='胜' then 1 else 0 end)'胜',sum(case when shengfu='负' then 1 else 0 end)'负' from #tmp group by rq
2) select N.rq,N.勝,M.負 from (
select rq,勝=count(*) from #tmp where shengfu='胜'group by rq)N inner join
(select rq,負=count(*) from #tmp where shengfu='负'group by rq)M on N.rq=M.rq
3)select a.col001,a.a1 胜,b.b1 负 from
(select col001,count(col001) a1 from temp1 where col002='胜' group by col001) a,
(select col001,count(col001) b1 from temp1 where col002='负' group by col001) b
where a.col001=b.col001
2.请教一个面试中遇到的SQL语句的查询问题
表中有A B C三列,用SQL语句实现：当A列大于B列时选择A列否则选择B列，当B列大于C列时选择B列否则选择C列。
------------------------------------------
select (case when a>b then a else b end ),
(case when b>c then b esle c end)
from table_name
3.面试题：一个日期判断的sql语句？
请取出tb_send表中日期(SendTime字段)为当天的所有记录?(SendTime字段为datetime型，包含日期与时间)
------------------------------------------
select * from tb where datediff(dd,SendTime,getdate())=0
4.有一张表，里面有3个字段：语文，数学，英语。其中有3条记录分别表示语文70分，数学80分，英语58分，
请用一条sql语句查询出这三条记录并按以下条件显示出来（并写出您的思路）：
大于或等于80表示优秀，大于或等于60表示及格，小于60分表示不及格。
显示格式：
语文 数学 英语
及格 优秀 不及格
------------------------------------------
select
(case when 语文>=80 then '优秀'
when 语文>=60 then '及格'
else '不及格') as 语文,
(case when 数学>=80 then '优秀'
when 数学>=60 then '及格'
else '不及格') as 数学,
(case when 英语>=80 then '优秀'
when 英语>=60 then '及格'
else '不及格') as 英语,
from table
5.在sqlserver2000中请用sql创建一张用户临时表和系统临时表，里面包含两个字段ID和IDValues,类型都是int型，并解释下两者的区别?
------------------------------------------
用户临时表:create table #xx(ID int, IDValues int)
系统临时表:create table ##xx(ID int, IDValues int)
区别:
用户临时表只对创建这个表的用户的Session可见,对其他进程是不可见的.
当创建它的进程消失时这个临时表就自动删除.
全局临时表对整个SQL Server实例都可见,但是所有访问它的Session都消失的时候,它也自动删除.
6.sqlserver2000是一种大型数据库，他的存储容量只受存储介质的限制，请问它是通过什么方式实现这种无限容量机制的。
------------------------------------------
它的所有数据都存储在数据文件中(*.dbf),所以只要文件够大,SQL Server的存储容量是可以扩大的.
SQL Server 2000 数据库有三种类型的文件：
主要数据文件
主要数据文件是数据库的起点，指向数据库中文件的其它部分。每个数据库都有一个主要数据文件。主要数据文件的推荐文件扩展名是 .mdf。
次要数据文件
次要数据文件包含除主要数据文件外的所有数据文件。有些数据库可能没有次要数据文件，而有些数据库则有多个次要数据文件。次要数据文件的推荐文件扩展名是 .ndf。
日志文件
日志文件包含恢复数据库所需的所有日志信息。每个数据库必须至少有一个日志文件，但可以不止一个。日志文件的推荐文件扩展名是 .ldf。
7.请用一个sql语句得出结果
从table1,table2中取出如table3所列格式数据，注意提供的数据及结果不准确，只是作为一个格式向大家请教。
如使用存储过程也可以。
table1
月份mon 部门dep 业绩yj
-------------------------------
一月份 01 10
一月份 02 10
一月份 03 5
二月份 02 8
二月份 04 9
三月份 03 8
table2
部门dep 部门名称dname
--------------------------------
01 国内业务一部
02 国内业务二部
03 国内业务三部
04 国际业务部
table3 （result）
部门dep 一月份 二月份 三月份
--------------------------------------
01 10 null null
02 10 8 null
03 null 5 8
04 null null 9
------------------------------------------
1)
select a.部门名称dname,b.业绩yj as '一月份',c.业绩yj as '二月份',d.业绩yj as '三月份'
from table1 a,table2 b,table2 c,table2 d
where a.部门dep = b.部门dep and b.月份mon = '一月份' and
a.部门dep = c.部门dep and c.月份mon = '二月份' and
a.部门dep = d.部门dep and d.月份mon = '三月份' and
2)
select a.dep,
sum(case when b.mon=1 then b.yj else 0 end) as '一月份',
sum(case when b.mon=2 then b.yj else 0 end) as '二月份',
sum(case when b.mon=3 then b.yj else 0 end) as '三月份',
sum(case when b.mon=4 then b.yj else 0 end) as '四月份',
sum(case when b.mon=5 then b.yj else 0 end) as '五月份',
sum(case when b.mon=6 then b.yj else 0 end) as '六月份',
sum(case when b.mon=7 then b.yj else 0 end) as '七月份',
sum(case when b.mon=8 then b.yj else 0 end) as '八月份',
sum(case when b.mon=9 then b.yj else 0 end) as '九月份',
sum(case when b.mon=10 then b.yj else 0 end) as '十月份',
sum(case when b.mon=11 then b.yj else 0 end) as '十一月份',
sum(case when b.mon=12 then b.yj else 0 end) as '十二月份',
from table2 a left join table1 b on a.dep=b.dep
==================================================================
XmlDocument xmldoc = new XmlDocument();
xmldoc.Load(Server.MapPath("userinfo.xml"));
XmlElement root=xmldoc.DocumentElement;
XmlNodeList nodelist = root.SelectNodes("//user");
DataSet ds = new DataSet("myds");
DataTable tb = new DataTable("userinfo");
ds.Tables.Add(tb);
ds.Tables[0].Columns.Add("UserID", typeof(int));
ds.Tables[0].Columns.Add("UserName", typeof(string));
ds.Tables[0].Columns.Add("UserPwd", typeof(string));
ds.Tables[0].Columns.Add("Email", typeof(string));
ds.Tables[0].Columns.Add("DetailedID", typeof(string));
foreach(XmlNode node in nodelist)
{
DataRow row=ds.Tables[0].NewRow();
row["UserID"] = node.SelectSingleNode("UserID").InnerText;
row["UserName"] = node.SelectSingleNode("UserName").InnerText;
row["UserPwd"] = node.SelectSingleNode("UserPwd").InnerText;
row["Email"] = node.SelectSingleNode("Email").InnerText;
row["DetailedID"] = node.SelectSingleNode("DetailedID").InnerText;
ds.Tables[0].Rows.Add(row);
}
GridView gv = new GridView();
gv.DataSource = ds.Tables[0];
gv.DataBind();
from1.Controls.Add(gv);