--查询列中含有重复的数据
Select distinct (code) ,Count(*) as RecordCount
From user_visit_cnws
Group by code
having Count(*) >1

---行转列

select t.name as a,sum(t.val) as aa,t.dm
from ( select '医保总额' as name,f.ybfwze as val,d.jc as dm from sfmis.TB_HIS_FEEREC f, sfmis.TB_DIC_YLJG d where f.yljgdm=d.dmxdmz group by d.jc,f.ybfwze
    union all
    select '自费总额' as name,f.grzf as val ,d.jc as dm from sfmis.TB_HIS_FEEREC f,sfmis.TB_DIC_YLJG d where f.yljgdm=d.dmxdmz group by d.jc,f.grzf) t
group by t.name,t.dm

----SQL SERVER

执行计划 

SELECT 
    substring(text,qs.statement_start_offset/2
        ,(CASE    
            WHEN qs.statement_end_offset = -1 THEN len(convert(nvarchar(max), text)) * 2 
            ELSE qs.statement_end_offset 
        END - qs.statement_start_offset)/2) 
    ,qs.plan_generation_num as recompiles
    ,qs.execution_count as execution_count
    ,qs.total_elapsed_time - qs.total_worker_time as total_wait_time
    ,qs.total_worker_time as cpu_time
    ,qs.total_logical_reads as reads
    ,qs.total_logical_writes as writes
FROM sys.dm_exec_query_stats qs
    CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) st
    LEFT JOIN sys.dm_exec_requests r 
        ON qs.sql_handle = r.sql_handle
ORDER BY 3 DESC

SQL SERVER 2005查询死锁进程
select
request_session_id as spid,
resource_type,
db_name(resource_database_id) as dbName,
resource_description,
resource_associated_entity_id,
request_mode as mode,
request_status as Status
from
sys.dm_tran_locks
--Result:
/*
进程ID 资源类型 数据库 资源描述 资源关链ID 锁类型 进程状态
----------- ------------- ------ -------------------- ----------------------------- ----- ------
59 DATABASE Gepro 0 S GRANT
58 DATABASE Gepro 0 S GRANT
57 DATABASE Gepro 0 S GRANT
56 DATABASE Gepro 0 S GRANT
58 PAGE Gepro 1:1904 72057594039435264 IS GRANT
57 PAGE Gepro 1:1904 72057594039435264 IX GRANT
58 OBJECT              Gepro 853578079 IS GRANT
57 OBJECT Gepro 853578079 IX GRANT
57 KEY Gepro (020068e8b274) 72057594039435264     X      GRANT
58 KEY Gepro (020068e8b274) 72057594039435264 S      WAIT
(9 行受影响)
*/
-->SQL SERVER 2000查询死锁进程
SELECT DISTINCT
'进程ID' = STR(a.spid, 4)
, '进程ID状态' = CONVERT(CHAR(10), a.status)
, '死锁进程ID' = STR(a.blocked, 2)
, '工作站名称' = CONVERT(CHAR(10), a.hostname)
, '执行命令的用户' = CONVERT(CHAR(10), SUSER_NAME(a.uid))
, '数据库名' = CONVERT(CHAR(10), DB_NAME(a.dbid))
, '应用程序名' = CONVERT(CHAR(10), a.program_name)
, '正在执行的命令' = CONVERT(CHAR(16), a.cmd)
, '登录名' = a.loginame
, '执行语句' = b.text
FROM master..sysprocesses a CROSS APPLY
sys.dm_exec_sql_text(a.sql_handle) b
WHERE a.blocked IN ( SELECT blocked
FROM master..sysprocesses )
-- and blocked <> 0
ORDER BY STR(spid, 4)
--Result
/*
进程 ID  进程ID   状态  死锁进程ID  工作站名称 执行命令的用户 数据库名 应用程序名 正在执行的命令 登录名 执行语句
---- ---------- ------ ---------- ---------- ---------- ---------- ---------------- ---------------------------------------------------------------------- -------------------------
56 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
57 sleeping 0 DC91229126 sa Gepro Microsoft AWAITING COMMAND DC91229126FF442\Administrator SET STATISTICS XML OFF
58 suspended 57 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator begin tran select * from ta
59 runnable 0 DC91229126 sa Gepro Microsoft SELECT DC91229126FF442\Administrator SELECT DISTINCT
60 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator SET FMTONLY OFF;
62 sleeping 0 DC91229126 sa Gepro Toad for S AWAITING COMMAND DC91229126FF442\Administrator
*/
--查连接住信息(spid:57、58)
select connect_time,last_read,last_write,most_recent_sql_handle
from sys.dm_exec_connections where session_id in(57,58)
--查看会话信息
select login_time,host_name,program_name,login_name,last_request_start_time,last_request_end_time
from sys.dm_exec_sessions where session_id in(57,58)
--查看阻塞正在执行 的请求
select
session_id,blocking_session_id,wait_type,wait_time,wait_resource
from
sys.dm_exec_requests
where
blocking_session_id>0-- 正在阻塞请求的会话的 ID。如果此列是 NULL，则不会阻塞请求
/*
session_id,blocking_session_id,wait_type,wait_time,wait_resource
58 57 LCK_M_S 2116437 KEY: 6:72057594039435264 (020068e8b274)
*/
--查看正在执行的SQL语句
select
a.session_id,sql.text,a.most_recent_sql_handle
from
sys.dm_exec_connections a
cross apply
sys.dm_exec_sql_text(a.most_recent_sql_handle) as SQL --也可用函数fn_get_sql通过most_recent_sql_handle得到执行语句
where
a.Session_id in(57,58)
/*
session_id text
----------- -----------------------------------------------
57 SET STATISTICS XML OFF
58 begin tran select * from ta
*/

处理方法:
法一：
-- 连接窗口2
begin tran
select * from ta with (nolock)--用nolock:业务数据不断变化中,如销售查看当月时可用。
法二：
阻塞2(索引):
处理方法: 加索引
create index IX_Ta_Col1 on Ta(Col1)--用COl1列上创索引,当更新时条件:COl1=102会用到索引IX_Ta_Col1上得到一个排它键的范围锁
---------------------------- 连接窗口1 -------------------------------------------------
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE
--针对会话设置了 TRANSACTION ISOLATION LEVEL
--SERIALIZABLE 幻影读、不可重复读和脏读都不允许
begin tran
update ta set col2='BB' where COl1=102
--rollback tran
----------------------------- 连接窗口2------------------------------------------------
begin tran
select * from ta
法三：设置当前查询隔离级别
-----------------------------连接窗口 2------------------------------------------------
SET TRANSACTION ISOLATION LEVEL READ COMMITTED --设置会话已提交读:指定语句不能读取已由其他事务修改但尚未提交的数据
begin tran
select * from ta

1、事务要尽量短

--查看死锁牺牲品

SELECT  '进程ID[SPID]' = STR(a.spid, 4)
  , '进程状态' = CONVERT(CHAR(10), a.status)
  , '分块进程ID' = STR(a.blocked, 2)
  , '服务器名称' = CONVERT(CHAR(10), a.hostname)
  , '执行用户' = CONVERT(CHAR(10), SUSER_NAME(a.uid))
  , '数据库名' = CONVERT(CHAR(10), DB_NAME(a.dbid))
  , '应用程序名' = CONVERT(CHAR(10), a.program_name)
  , '正在执行的命令' = CONVERT(CHAR(16), a.cmd)
  , '累计CPU时间' = STR(a.cpu, 7)
  , 'IO' = STR(a.physical_io, 7)
  , '登录名' = a.loginame
  , '执行sql' = b.text
FROM    master..sysprocesses a CROSS APPLY
    sys.dm_exec_sql_text(a.sql_handle) b
WHERE   blocked <> 0
ORDER BY spid

--查看进程运行状况

   SELECT  '进程ID' = STR(spid, 4)
      , '进程ID状态' = CONVERT(CHAR(10), status)
      , '分块进程ID' = STR(blocked, 2)
      , '工作站名称' = CONVERT(CHAR(10), hostname)
      , '执行用户' = CONVERT(CHAR(10), SUSER_NAME(uid))
      , '数据库名' = CONVERT(CHAR(10), DB_NAME(dbid))
      , '应用程序名' = CONVERT(CHAR(10), program_name)
      , '正在执行的命令' = CONVERT(CHAR(16), cmd)
      , '累计CPU时间' = STR(cpu, 7)
      , 'IO' = STR(physical_io, 7)
      , '登录名' = loginame
FROM    master..sysprocesses
    --where blocked = 0
ORDER BY spid

--blocked = 0表示没有阻塞的进程ID；

--查询锁类型

select 进程id=a.req_spid
  ,数据库=db_name(rsc_dbid)
  ,类型=case rsc_type when 1 then 'NULL 资源（未使用）'
  when 2 then '数据库'
  when 3 then '文件'
  when 4 then '索引'
  when 5 then '表'
  when 6 then '页'
  when 7 then '键'
  when 8 then '扩展盘区'
  when 9 then 'RID（行 ID)'
  when 10 then '应用程序'
  end
  ,对象id=rsc_objid
  ,对象名=b.obj_name
  ,rsc_indid
from master..syslockinfo a left join #t b on a.req_spid=b.req_spid