如何查看客户端的IP地址，机器名，MAC地址，登陆名等信息
select s.session_id,s.login_time,s.host_name,p.loginame,s.program_name,c.client_net_address,c.client_tcp_port,p.net_address as client_mac_address, c.local_net_address,c.local_tcp_port,c.net_transport
from sys.dm_exec_connections c join sys.dm_exec_sessions s on c.session_id = s.session_id join sys.sysprocesses p
on s.session_id = p.spid
-------------------------------------------------
SELECT * FROM (select a=1 union select 2 union select 3 union select 4) T
where POWER(2,a) = 8
----------------------------------
计算3的4次方的值：select Power(3,4)
计算8开根3后的值：select power(8.0,1.0/3)
计算16的平方根:select sqrt(16)
-----------------------------------------------
SQL取每个月的最后一天（convert中112是yymmdd格式）:
SQL中数值型日期格式如20100223：select convert(varchar(8),getdate(),112)
上月底最后一天:select getdate()-day(getdate())
...select convert(varchar(8),(getdate()-day(getdate())),112)
本月底最后一天:select dateadd(month,1,getdate())-day(dateadd(month,1,getdate()))
...select convert(varchar(8),(getdate()-day(getdate())),112)
日期相减：
select datediff(day,(select convert(varchar(8),(getdate()-day(getdate())),112)),(select convert(varchar(8),(dateadd(month,1,getdate())-day(dateadd(month,1,getdate()))),112)
))
日期相除：
select a=((select cast(convert(varchar(30),(dateadd(month,1,getdate())-day(dateadd(month,1,getdate()))),112 ) as float))/(select cast(convert(varchar(30),(getdate()-day(getdate())),112) as float))
-1.0 )/12.0
select 跨库查询：
select [db]..table.字段 from [db]..table
循环出最近一个月的所有日期：
declare @dateA datetime
set @dateA = dateadd(Month,-1,getdate())
declare @tmp table (TheDate datetime)
while datediff(DAY,@dateA,getdate()) >= 0
begin
insert into @tmp values (@dateA)
set @dateA = dateadd(day,1,@dateA)
end
SELECT * FROM @tmp
同样的方法可以循环出两个时间之间的月份
游标的简单例子：
table1结构如下
id int
name varchar(50)
declare @id int
declare @name varchar(50)
declare cursor1 cursor for --定义游标cursor1
select * from table1 --使用游标的对象集(跟据需要填入select)
open cursor1 --打开游标
fetch next from cursor1 into @id,@name --将游标向下移行，获取的数据放入之前定义的变量@id,@name中
while @@fetch_status=0 --判断FETCH 语句成功获取数据
begin
update table1 set name=name+'1'
where id=@id --进行相应处理(跟据需要填入SQL文)
fetch next from cursor1 into @id,@name --将游标向下移行
end
close cursor1 --关闭游标
deallocate cursor1 --删除游标,删除后不可再用
------------------------------------------------------------
另一示例,利用游标更新数据：
use pubs
go
declare @au_id char(12)
declare @au_lname char(24)
declare @au_fname char(24)
/*声明游标，注意for update of..*/
declare cur_authors cursor for
select au_id,au_lname,au_fname
from authors where au_lname= 'ringer '
for update of au_fname
open cur_authors
fetch cur_authors into @au_id,@au_lname,@au_fname
while (@@fetch_status <> -1)
begin
/*注意where current of..*/
update authors set au_fname= 'AA '
where current of cur_authors
fetch cur_authors into @au_id,@au_lname,@au_fname
end
if (@@fetch_status=-1)
begin
close cur_authors
deallocate cur_authors
end
--------------------
Select @@CURSOR_ROWS 可以得到当前游标中存在的数据行数。
注意：此变量为一个连接上的全局变量，因此只对应最后一次打开的游标。
-------------------------------------------------
打开游标
全局游标：Open Global MyCursor
局部游标: Open MyCursor
---------------------------
事务举例：
begin transaction
declare @k int
set @k=0
insert into a values（'1','str'）
if @@error<>0
set @k=@k+1
insert into b values（'2','str'）
if @@error<>0
set @k=@k+1
update a set name='stu' where id='1'
if @@error<>0
set @k=@k+1
if @K<>0
begin
rollback transaction
return
end
commit transaction
-------------------------
SQL 2008 数据库优化常用脚本：
-查询某个数据库的连接数
select count(*) from Master.dbo.SysProcesses where dbid=db_id()
--前10名其他等待类型
SELECT TOP 10 *
from sys.dm_os_wait_stats
ORDER BY wait_time_ms DESC
SELECT *FROM sys.dm_os_wait_stats WHERE wait_type like 'PAGELATCH%'
OR wait_type like 'LAZYWRITER_SLEEP%'
--CPU的压力
SELECT scheduler_id, current_tasks_count, runnable_tasks_count
FROM sys.dm_os_schedulers
WHERE scheduler_id < 255
--表现最差的前10名使用查询
SELECT TOP 10 ProcedureName = t.text,
ExecutionCount = s.execution_count,
AvgExecutionTime = isnull ( s.total_elapsed_time / s.execution_count, 0 ),
AvgWorkerTime = s.total_worker_time / s.execution_count,
TotalWorkerTime = s.total_worker_time,
MaxLogicalReads = s.max_logical_reads,
MaxPhysicalReads = s.max_physical_reads,
MaxLogicalWrites = s.max_logical_writes,
CreationDateTime = s.creation_time,
CallsPerSecond = isnull ( s.execution_count / datediff ( second , s.creation_time, getdate ()), 0 )
FROM sys.dm_exec_query_stats s
CROSS APPLY sys.dm_exec_sql_text( s.sql_handle ) t ORDER BY
s.max_physical_reads DESC
---------------------
SELECT SUM(signal_wait_time_ms) AS total_signal_wait_time_ms总信号等待时间 ,
SUM(wait_time_ms - signal_wait_time_ms) AS resource_wait_time_ms资源的等待时间,
SUM(signal_wait_time_ms) * 1.0 / SUM (wait_time_ms) * 100 AS [signal_wait_percent信号等待％],
SUM(wait_time_ms - signal_wait_time_ms) * 1.0 / SUM (wait_time_ms) * 100 AS [resource_wait_percent资源等待％]
FROM sys.dm_os_wait_stats
--一个信号等待时间过多对资源的等待时间那么你的CPU是目前的一个瓶颈。
-----------------------------------------------
--查看进程所执行的SQL语句
if (select COUNT(*) from master.dbo.sysprocesses) > 500
begin
select text,CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle) from master.sys.sysprocesses a
end
--------------------
select text,a.* from master.sys.sysprocesses a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
where a.spid = '51'
dbcc inputbuffer(53)
with tb
as
(
select blocking_session_id,
session_id,db_name(database_id) as dbname,text from master.sys.dm_exec_requests a
CROSS APPLY master.sys.dm_exec_sql_text(a.sql_handle)
),
tb1 as
(
select a.*,login_time,program_name,client_interface_name,login_name,cpu_time,memory_usage*8 as 'memory_usage(KB)',
total_scheduled_time,reads,writes,logical_reads
from tb a inner join master.sys.dm_exec_sessions b
on a.session_id=b.session_id
)
select a.*,connect_time,client_tcp_port,client_net_address from tb1 a inner join master.sys.dm_exec_connections b on a.session_id=b.session_id
--当前进程数
select * from master.dbo.sysprocesses
order by cpu desc
--查看当前活动的进程数
sp_who active
--查询是否由于连接没有释放引起CPU过高
select * from master.dbo.sysprocesses
where spid> 50
and waittype = 0x0000
and waittime = 0
and status = 'sleeping '
and last_batch < dateadd(minute, -10, getdate())
and login_time < dateadd(minute, -10, getdate())
--强行释放空连接
select 'kill ' + rtrim(spid) from master.dbo.sysprocesses
where spid> 50
and waittype = 0x0000
and waittime = 0
and status = 'sleeping '
and last_batch < dateadd(minute, -60, getdate())
and login_time < dateadd(minute, -60, getdate())
--查看当前占用 cpu 资源最高的会话和其中执行的语句(及时CPU)
select spid,cmd,cpu,physical_io,memusage,
(select top 1 [text] from ::fn_get_sql(sql_handle)) sql_text
from master..sysprocesses order by cpu desc,physical_io desc
--查看缓存中重用次数少，占用内存大的查询语句（当前缓存中未释放的）--全局
SELECT TOP 100 usecounts, objtype, p.size_in_bytes,[sql].[text]
FROM sys.dm_exec_cached_plans p OUTER APPLY sys.dm_exec_sql_text (p.plan_handle) sql
ORDER BY usecounts,p.size_in_bytes desc
SELECT top 25 qt.text,qs.plan_generation_num,qs.execution_count,dbid,objectid
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(sql_handle) as qt
WHERE plan_generation_num >1
ORDER BY qs.plan_generation_num
SELECT top 50 qt.text AS SQL_text ,SUM(qs.total_worker_time) AS total_cpu_time,
SUM(qs.execution_count) AS total_execution_count,
SUM(qs.total_worker_time)/SUM(qs.execution_count) AS avg_cpu_time,
COUNT(*) AS number_of_statements
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
GROUP BY qt.text
ORDER BY total_cpu_time DESC --统计总的CPU时间
--ORDER BY avg_cpu_time DESC --统计平均单次查询CPU时间
-- 计算可运行状态下的工作进程数量
SELECT COUNT(*) as workers_waiting_for_cpu,s.scheduler_id
FROM sys.dm_os_workers AS o
INNER JOIN sys.dm_os_schedulers AS s
ON o.scheduler_address=s.scheduler_address
AND s.scheduler_id<255
WHERE o.state='RUNNABLE'
GROUP BY s.scheduler_id
--表空间大小查询
create table #tb(表名 sysname,记录数 int,保留空间 varchar(100),使用空间 varchar(100),索引使用空间 varchar(100),未用空间 varchar(100))
insert into #tb exec sp_MSForEachTable 'EXEC sp_spaceused ''?'''
select * from #tb
go
SELECT
表名,
记录数,
cast(ltrim(rtrim(replace(保留空间,'KB',''))) as int)/1024 保留空间MB,
cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024 使用空间MB,
cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024/1024.00 使用空间GB,
cast(ltrim(rtrim(replace(索引使用空间,'KB',''))) as int)/1024 索引使用空间MB,
cast(ltrim(rtrim(replace(未用空间,'KB',''))) as int)/1024 未用空间MB
FROM #tb
WHERE cast(ltrim(rtrim(replace(使用空间,'KB',''))) as int)/1024 > 0
--order by 记录数 desc
ORDER BY 使用空间MB DESC
DROP TABLE #tb
--查询是否由于连接没有释放引起CPU过高
select * from master.dbo.sysprocesses
where spid> 50
and waittype = 0x0000
and waittime = 0
and status = 'sleeping '
and last_batch < dateadd(minute, -10, getdate())
and login_time < dateadd(minute, -10, getdate())
--强行释放空连接
select 'kill ' + rtrim(spid) from master.dbo.sysprocesses
where spid> 50
and waittype = 0x0000
and waittime = 0
and status = 'sleeping '
and last_batch < dateadd(minute, -60, getdate())
and login_time < dateadd(minute, -60, getdate())
----查看当前占用 cpu 资源最高的会话和其中执行的语句(及时CPU)
select spid,cmd,cpu,physical_io,memusage,
(select top 1 [text] from ::fn_get_sql(sql_handle)) sql_text
from master..sysprocesses order by cpu desc,physical_io desc
----查看缓存中重用次数少，占用内存大的查询语句（当前缓存中未释放的）--全局
SELECT TOP 100 usecounts, objtype, p.size_in_bytes,[sql].[text]
FROM sys.dm_exec_cached_plans p OUTER APPLY sys.dm_exec_sql_text (p.plan_handle) sql
ORDER BY usecounts,p.size_in_bytes desc
SELECT top 25 qt.text,qs.plan_generation_num,qs.execution_count,dbid,objectid
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(sql_handle) as qt
WHERE plan_generation_num >1
ORDER BY qs.plan_generation_num
SELECT top 50 qt.text AS SQL_text ,SUM(qs.total_worker_time) AS total_cpu_time,
SUM(qs.execution_count) AS total_execution_count,
SUM(qs.total_worker_time)/SUM(qs.execution_count) AS avg_cpu_time,
COUNT(*) AS number_of_statements
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
GROUP BY qt.text
ORDER BY total_cpu_time DESC --统计总的CPU时间
--ORDER BY avg_cpu_time DESC --统计平均单次查询CPU时间
-- 计算可运行状态下的工作进程数量
SELECT COUNT(*) as workers_waiting_for_cpu,s.scheduler_id
FROM sys.dm_os_workers AS o
INNER JOIN sys.dm_os_schedulers AS s
ON o.scheduler_address=s.scheduler_address
AND s.scheduler_id<255
WHERE o.state='RUNNABLE'
GROUP BY s.scheduler_id
-------------------------------------
SELECT creation_time N'语句编译时间'
,last_execution_time N'上次执行时间'
,total_physical_reads N'物理读取总次数'
,total_logical_reads/execution_count N'每次逻辑读次数'
,total_logical_reads N'逻辑读取总次数'
,total_logical_writes N'逻辑写入总次数'
, execution_count N'执行次数'
, total_worker_time/1000 N'所用的CPU总时间ms'
, total_elapsed_time/1000 N'总花费时间ms'
, (total_elapsed_time / execution_count)/1000 N'平均时间ms'
,SUBSTRING(st.text, (qs.statement_start_offset/2) + 1,
((CASE statement_end_offset
WHEN -1 THEN DATALENGTH(st.text)
ELSE qs.statement_end_offset END
- qs.statement_start_offset)/2) + 1) N'执行语句'
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st
where SUBSTRING(st.text, (qs.statement_start_offset/2) + 1,
((CASE statement_end_offset
WHEN -1 THEN DATALENGTH(st.text)
ELSE qs.statement_end_offset END
- qs.statement_start_offset)/2) + 1) not like '%fetch%'
ORDER BY total_elapsed_time / execution_count DESC