实用SQL语句

查询表内容
SELECT
表名=case when a.colorder=1 then
d.name else '' end,
表说明=case when a.colorder=1 then
isnull(f.value,'') else '' end,
字段序号=a.colorder,
字段名=a.name,
标识=case when COLUMNPROPERTY(
a.id,a.name,'IsIdentity')=1 then '√'else '' end,
主键=case when exists(SELECT 1 FROM
sysobjects where xtype='PK' and name in (
SELECT name FROM sysindexes WHERE
indid in(
SELECT
indid FROM sysindexkeys WHERE id = a.id AND colid=a.colid
))) then '√' else '' end,

类型=b.name,

占用字节数=a.length,

长度=COLUMNPROPERTY(a.id,a.name,'PRECISION'),

小数位数=isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0),

允许空=case when
a.isnullable=1 then '√'else '' end,
默认值=isnull(e.text,''),

字段说明=isnull(g.[value],'')

FROM syscolumns a

left join systypes
b on a.xtype=b.xusertype
inner join sysobjects d on a.id=d.id
and d.xtype='U' and d.name<>'dtproperties'
left join syscomments e on
a.cdefault=e.id
left join sysproperties g on
a.id=g.id and a.colid=g.smallid
left join sysproperties f on
d.id=f.id and f.smallid=0
--where d.name='要查询的表'
--如果只查询指定表,加上此条件
order by a.id,a.colorder

========================================================

SQL交*表实例

很简单的一个东西，见网上好多朋友问“怎么实现交*表？”，以下是我写的一个例子，数据库基于SQL
SERVER 2000。
建表：

在查询分析器里运行：

CREATE TABLE [Test]
(
[id] [int]
IDENTITY (1, 1) NOT NULL ,
[name] [nvarchar] (50) COLLATE
Chinese_PRC_CI_AS NULL ,
[subject] [nvarchar] (50) COLLATE
Chinese_PRC_CI_AS NULL ,
[Source] [numeric](18, 0) NULL

) ON [PRIMARY]

GO
INSERT INTO [test]
([name],[subject],[Source]) values (N'张三',N'语文',60)
INSERT INTO [test]
([name],[subject],[Source]) values (N'李四',N'数学',70)
INSERT INTO [test]
([name],[subject],[Source]) values (N'王五',N'英语',80)
INSERT INTO [test]
([name],[subject],[Source]) values (N'王五',N'数学',75)
INSERT INTO [test]
([name],[subject],[Source]) values (N'王五',N'语文',57)
INSERT INTO [test]
([name],[subject],[Source]) values (N'李四',N'语文',80)
INSERT INTO [test]
([name],[subject],[Source]) values (N'张三',N'英语',100)
Go
交*表语句的实现：
--用于：交*表的列数是确定的
select name,sum(case subject when
'数学' then source else 0 end) as '数学',
sum(case subject when '英语' then
source else 0 end) as '英语',
sum(case subject when '语文' then
source else 0 end) as '语文'
from test
group by name
--用于：交*表的列数是不确定的
declare @sql varchar(8000)

set @sql = 'select
name,'
select @sql
= @sql + 'sum(case subject when '''+subject+'''
then source else 0 end) as
'''+subject+''','
from (select distinct subject from
test) as a
select
@sql = left(@sql,len(@sql)-1) + ' from test group by name'
exec(@sql)
go
================================================================================

SQL Server
存储过程的分页方案比拼
出处

SQL Server
存储过程的分页，这个问题已经讨论过几年了，很多朋友在问我，所以在此发表一下我的观点
建立表：
CREATE TABLE [TestTable] (

[ID] [int] IDENTITY
(1, 1) NOT NULL ,
[FirstName] [nvarchar] (100) COLLATE
Chinese_PRC_CI_AS NULL ,
[LastName] [nvarchar] (100) COLLATE
Chinese_PRC_CI_AS NULL ,
[Country] [nvarchar] (50) COLLATE
Chinese_PRC_CI_AS NULL ,
[Note] [nvarchar] (2000) COLLATE
Chinese_PRC_CI_AS NULL
) ON [PRIMARY]
GO

插入数据：(2万条，用更多的数据测试会明显一些)

SET IDENTITY_INSERT
TestTable ON
declare @i int
set @i=1
while @i<=20000
begin
insert into TestTable([id],
FirstName, LastName, Country,Note) values(@i,
'FirstName_XXX','LastName_XXX','Country_XXX','Note_XXX')
set @i=@i+1
end
SET IDENTITY_INSERT TestTable OFF

-------------------------------------

分页方案一：(利用Not
In和SELECT TOP分页)
语句形式：
SELECT TOP 10 *
FROM TestTable
WHERE (ID NOT IN
(SELECT TOP 20 id
FROM TestTable
ORDER BY id))
ORDER BY ID
SELECT TOP 页大小 *
FROM TestTable
WHERE (ID NOT IN
(SELECT TOP 页大小*页数 id

FROM 表

ORDER BY id))

ORDER BY ID

-------------------------------------

分页方案二：(利用ID大于多少和SELECT TOP分页）

语句形式：

SELECT TOP 10 *

FROM TestTable

WHERE (ID >

(SELECT MAX(id)

FROM (SELECT TOP 20
id
FROM TestTable

ORDER BY id) AS T))

ORDER BY ID

SELECT TOP 页大小 *

FROM TestTable

WHERE (ID >

(SELECT MAX(id)

FROM (SELECT TOP
页大小*页数 id
FROM 表

ORDER BY id) AS T))

ORDER BY ID

-------------------------------------

分页方案三：(利用SQL的游标存储过程分页)

create procedure
XiaoZhengGe
@sqlstr
nvarchar(4000), --查询字符串
@currentpage int, --第N页

@pagesize int
--每页行数
as

set nocount on

declare @P1 int,
--P1是游标的id
@rowcount int
exec sp_cursoropen @P1
output,@sqlstr,@scrollopt=1,@ccopt=1,@rowcount=@rowcount output
select ceiling(1.0*@rowcount/@pagesize) as 总页数--,@rowcount as
总行数,@currentpage as 当前页
set
@currentpage=(@currentpage-1)*@pagesize+1
exec sp_cursorfetch
@P1,16,@currentpage,@pagesize
exec sp_cursorclose @P1

set nocount off

其它的方案：如果没有主键，可以用临时表，也可以用方案三做，但是效率会低。

建议优化的时候，加上主键和索引，查询效率会提高。

通过SQL
查询分析器，显示比较：我的结论是:
分页方案二：(利用ID大于多少和SELECT
TOP分页）效率最高，需要拼接SQL语句
分页方案一：(利用Not In和SELECT TOP分页)
效率次之，需要拼接SQL语句
分页方案三：(利用SQL的游标存储过程分页) 效率最差，但是最为通用

在实际情况中，要具体分析。

====================================================================================

得到随机排序结果

出处

SELECT *
FROM Northwind..Orders

ORDER BY NEWID()

SELECT TOP 10 *

FROM
Northwind..Orders
ORDER BY NEWID()
====================================================================================

select

to_char(日期,'yyyymmdd')
DATE_ID,to_char(日期,'yyyy')||'年'||to_char(日期,'mm')||'月'||to_char(日期,'dd')||'日'
DATE_NAME,
to_char(日期,'yyyymm')
MONTH_ID,to_char(日期,'yyyy')||'年'||to_char(日期,'mm')||'月' MONTH_NAME,

'Q'||to_char(日期,'q.yyyy')
QUARTERID,to_char(日期,'yyyy')||'年第'||to_char(日期,'q')||'季度' QUARTERID_NAME,

to_char(日期,'yyyy')
YEAR_ID,to_char(日期,'yyyy')||'年' YEAR_NAME
from(
select
to_date('2000-01-01','yyyy-mm-dd')+(rownum-1) 日期 from user_objects where
rownum<367 and
to_date('2000-01-01','yyyy-mm-dd')+(rownum-1)<to_date('2001-01-01','yyyy-mm-dd')

);
--得到季度和月份对应关系
select distinct to_char(日期,'q')
季度,to_char(to_date('2001-01-01','yyyy-mm-dd')+(rownum-1),'yyyymm') 日期 from(

select
to_date('2001-01','yyyy-mm')+(rownum-1) 日期 from user_objects where rownum<367
and
to_date('2001-01-01','yyyy-mm-dd')+(rownum-1)<to_date('2002-01-01','yyyy-mm-dd')

);
--得到一年中的天数
select
to_char(to_date('2000-01-01','yyyy-mm-dd')+(rownum-1),'yyyy-mm-dd') 日期 from
user_objects where rownum<367 and
to_date('2000-01-01','yyyy-mm-dd')+(rownum-1)<to_date('2001-01-01','yyyy-mm-dd');

====================================================================================

获取一个数据库的所有存储过程,可以用

select * from
sysobjects where type='p'
====================================================================================

生成交*表的简单通用存储过程

出处

if exists (select * from
dbo.sysobjects where id = object_id(N'[dbo].[p_qry]') and OBJECTPROPERTY(id,
N'IsProcedure') = 1)
drop procedure [dbo].[p_qry]

GO
/*--生成交*表的简单通用存储过程

根据指定的表名,纵横字段,统计字段,自动生成交*表

并可根据需要生成纵横两个方向的合计

注意,横向字段数目如果大于纵向字段数目,将自动交换纵横字段

如果不要此功能,则去掉交换处理部分

--邹建 204.06--*/

/*--调用示例

exec p_qry
'syscolumns','id','colid','colid',1,1
--*/
create proc p_qry
@TableName sysname, --表名

@纵轴 sysname,
--交*表最左面的列
@横轴
sysname, --交*表最上面的列
@表体内容 sysname, --交*表的数数据字段

@是否加横向合计
bit,--为1时在交*表横向最右边加横向合计
@是否家纵向合计 bit --为1时在交*表纵向最下边加纵向合计

as
declare @s nvarchar(4000),@sql
varchar(8000)
--判断横向字段是否大于纵向字段数目,如果是,则交换纵横字段

set @s='declare @a
sysname
if(select
case when count(distinct ['+@纵轴+'])<count(distinct ['+@横轴+']) then 1 else 0
end
from
['+@TableName+'])=1
select @a=@纵轴,@纵轴=@横轴,@横轴=@a'
exec sp_executesql @s

,N'@纵轴 sysname
out,@横轴 sysname out'
,@纵轴 out,@横轴 out
--生成交*表处理语句
set @s='
set @s=''''
select @s=@s+'',[''+cast(['+@横轴+']
as varchar)+'']=sum(case ['+@横轴
+'] when ''''''+cast(['+@横轴+'] as
varchar)+'''''' then ['+@表体内容+'] else 0 end)''
from ['+@TableName+']

group by ['+@横轴+']'

exec sp_executesql
@s
,N'@s
varchar(8000) out'
,@sql out
--是否生成合计字段的处理
declare @sum1 varchar(200),@sum2
varchar(200),@sum3 varchar(200)
select @sum1=case @是否加横向合计

when 1 then
',[合计]=sum(['+@表体内容+'])'
else '' end
,@sum2=case @是否家纵向合计

when 1 then
'['+@纵轴+']=case grouping(['
+@纵轴+']) when 1 then ''合计'' else
cast(['
+@纵轴+'] as
varchar) end'
else
'['+@纵轴+']' end
,@sum3=case @是否家纵向合计

when 1 then ' with
rollup'
else '' end

--生成交*表

exec('select

from
['+@TableName+']
group by ['+@纵轴+']'+@sum3)

go