“where 1=1” 是表示选择全部   “where 1=2”全部不选，
如：
if @strwhere !=''
begin
set @strsql = 'select count(*) as total from [' + @tblname + '] where ' + @strwhere
end
else
begin
set @strsql = 'select count(*) as total from [' + @tblname + ']'
end

我们可以直接写成
set @strsql = 'select count(*) as total from [' + @tblname + '] where 1=1 安定 '+ @strwhere

2、收缩数据库
--重建索引
dbcc reindex
dbcc indexdefrag
--收缩数据和日志
dbcc shrinkdb
dbcc shrinkfile

3、压缩数据库
dbcc shrinkdatabase(dbname)

4、转移数据库给新用户以已存在用户权限
exec sp_change_users_login 'update_one','newname','oldname'
go

5、检查备份集
restore verifyonly from disk='e:\dvbbs.bak'

6、修复数据库
alter database [dvbbs] set single_user
go
dbcc checkdb('dvbbs',repair_allow_data_loss) with tablock
go
alter database [dvbbs] set multi_user
go

7、日志清除
set nocount on
declare @logicalfilename sysname,
        @maxminutes int,
        @newsize int

use     tablename             -- 要操作的数据库名
select  @logicalfilename = 'tablename_log',  -- 日志文件名
@maxminutes = 10,               -- limit on time allowed to wrap log.
        @newsize = 1                  -- 你想设定的日志文件的大小(m)

-- setup / initialize
declare @originalsize int
select @originalsize = size
  from sysfiles
  where name = @logicalfilename
select 'original size of ' + db_name() + ' log is ' +
        convert(varchar(30),@originalsize) + ' 8k pages or ' +
        convert(varchar(30),(@originalsize*8/1024)) + 'mb'
  from sysfiles
  where name = @logicalfilename
create table dummytrans
  (dummycolumn char (8000) not null)

declare @counter   int,
        @starttime datetime,
        @trunclog  varchar(255)
select  @starttime = getdate(),
        @trunclog = 'backup log ' + db_name() + ' with truncate_only'

dbcc shrinkfile (@logicalfilename, @newsize)
exec (@trunclog)
-- wrap the log if necessary.
while     @maxminutes > datediff (mi, @starttime, getdate()) -- time has not expired
      and @originalsize = (select size from sysfiles where name = @logicalfilename) 
      and (@originalsize * 8 /1024) > @newsize 
  begin -- outer loop.
    select @counter = 0
    while  ((@counter < @originalsize / 16) and (@counter < 50000))
      begin -- update
        insert dummytrans values ('fill log')