SQL温故系列两篇（一）

1.不允许保存更改。您所做的更改要求删除并重新创建以下表

关于SQL2008 “不允许保存更改。您所做的更改要求删除并重新创建以下表。

打开SQL SERVER 2008 工具-->选项-->Designers-->表设计器和数据库设计器，把“阻止保存要求重新创建表的更改”的勾去掉然后点“确定”即可。

2.同比环比

今年本月统计

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and datediff(d,VisitTime,getdate())>=0 and datediff(d,VisitTime,getdate())<=datepart(dd, getdate()) and datepart(mm, VisitTime) =datepart(mm, getdate()) and datepart(yy, VisitTime) =datepart(yy, getdate())

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and VisitTime between dateadd(day,-datepart(dd,getdate()),getdate()) and getdate()

去年本月统计

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and datediff(d,VisitTime,dateadd(year,-1,getdate()))>=0 and datediff(d,VisitTime,dateadd(year,-1,getdate()))<=datepart(dd, dateadd(year,-1,getdate())) and datepart(mm, VisitTime) =datepart(mm, dateadd(year,-1,getdate())) and datepart(yy, VisitTime) =datepart(yy, dateadd(year,-1,getdate()))

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and VisitTime between dateadd(day,-datepart(dd,dateadd(year,-1,getdate())),dateadd(year,-1,getdate())) and dateadd(year,-1,getdate())

今年上个月

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and datediff(d,VisitTime,dateadd(month,-1,getdate()))>=0 and datediff(d,VisitTime,dateadd(month,-1,getdate()))<=datepart(dd, dateadd(month,-1,getdate())) and datepart(mm, VisitTime) =datepart(mm, dateadd(month,-1,getdate())) and datepart(yy, VisitTime) =datepart(yy, dateadd(month,-1,getdate()))

select COUNT(0) from [jcms_normal_content_dbvisitcount] where dbid=91 and VisitTime between dateadd(day,-datepart(dd,dateadd(month,-1,getdate())),dateadd(month,-1,getdate())) and dateadd(month,-1,getdate())

保留两位小数：

select cast( cast(50 as  decimal(8,2) ) /  cast(49 as  decimal(8,2) ) as  decimal(8,2) )

删除一条数据：

select * from jcms_normal_content where Id=732;

delete from jcms_normal_content where Id=732;

将数据库的一张表数据复制到另一张表数据

insert into chaoxing_zgdzdx.dbo.jcms_normal_content (classid,AddDate,title,content) select classid,AddDate,title,content  from chaoxingpms_zgdzdx.dbo.jcms_normal_content where classid=1190

update dbo.jcms_normal_content set classid=188,Editor='admin',IsPass=1,ReadGroup='-1',Module='news',TemplateId=7 where classid=1190

将数据库一张表的数据更新到另一张表中

update a set a.Content=b.Content ,a.UpdateTime=b.UpdateTime from chaoxing_zgdzdx.dbo.jcms_normal_class a,chaoxingpms_zgdzdx.dbo.jcms_normal_class b where b.title='部门设置' and a.title=b.title

禁用外键约束

exec   sp_msforeachtable   'alter   table   ?   nocheck   constraint   all '

清空数据

truncate   table   表名

启用外键约束

exec   sp_msforeachtable   'alter   table   ?   check   constraint   all '

.读取10条到第20条记录

SELECT TOP 10 * FROM (SELECT TOP 20 * FROM tblORDER order by id) as tbl2 ORDER BY tbl2.id DESC

循环插入数据

declare @Id bigint
set @Id=28
while @Id<1000
begin
insert into jcms_normal_content_dbvisitcount (VisitIp,VisitTime,VisitIplocal,Module,dbID,Device,Browser) values('::1','2014-02-03 13:08:11.833',null,'link','91','pc',null)
set @Id=@Id+1
end

查询字段是否包含有这值的数据

SELECT * FROM jcms_normal_content WHERE charindex('http://boao.libsou.com/webpage/',customfield04)>0

排序按多个字段

当需要做一些数据统计或者业务比较复杂的时候，我们往往需要使用多个字段进行排序。如：
select * from Score order by Cno asc, Degree desc