SQL精妙語句

2、說明：拷貝表(拷貝資料,源表名：a 目標表名：b) (Access可用)
insert into b(a, b, c) select d,e,f from b;

3、說明：跨資料庫之間表的拷貝(具體資料使用絕對路徑) (Access可用)
insert into b(a, b, c) select d,e,f from b in ‘具體資料庫’ where 條件
例子：..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..

4、說明：子查詢(表名1：a 表名2：b)
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3)

5、說明：顯示文章、提交人和最後回覆時間
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b

6、說明：外連線查詢(表名1：a 表名2：b)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c

7、說明：線上檢視查詢(表名1：a )
select * from (SELECT a,b,c FROM a) T where t.a > 1;

8、說明：between的用法,between限制查詢資料範圍時包括了邊界值,not between不包括
select * from table1 where time between time1 and time2
select a,b,c, from table1 where a not between 數值1 and 數值2

9、說明：in 的使用方法
select * from table1 where a [not] in (‘值1’,’值2’,’值4’,’值6’)

10、說明：兩張關聯表，刪除主表中已經在副表中沒有的資訊 
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )

11、說明：四表聯查問題：
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....

12、說明：日程安排提前五分鐘提醒 
SQL: select * from 日程安排 where datediff('minute',f開始時間,getdate())>5

13、說明：一條sql 語句搞定資料庫分頁
select top 10 b.* from (select top 20 主鍵欄位,排序欄位 from 表名 order by 排序欄位 desc) a,表名 b where b.主鍵欄位 = a.主鍵欄位 order by a.排序欄位

14、說明：前10條記錄
select top 10 * form. table1 where 範圍

15、說明：選擇在每一組b值相同的資料中對應的a最大的記錄的所有資訊(類似這樣的用法可以用於論壇每月排行榜,每月熱銷產品分析,按科目成績排名,等等.)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)

16、說明：包括所有在 TableA 中但不在 TableB和TableC 中的行並消除所有重複行而派生出一個結果表
(select a from tableA ) except (select a from tableB) except (select a from tableC)

17、說明：隨機取出10條資料
select top 10 * from tablename order by newid()

18、說明：隨機選擇記錄
select newid()

19、說明：刪除重複記錄
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)

20、說明：列出資料庫裡所有的表名
select name from sysobjects where type='U'

21、說明：列出表裡的所有的
select name from syscolumns where id=object_id('TableName')

22、說明：列示type、vender、pcs欄位，以type欄位排列，case可以方便地實現多重選擇，類似select 中的case。
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type
顯示結果：
type vender pcs
電腦 A 1
電腦 A 1
光碟 B 2
光碟 A 2
手機 B 3
手機 C 3

23、說明：初始化表table1

TRUNCATE TABLE table1

24、說明：選擇從10到15的記錄
select top 5 * from (select top 15 * from table order by id asc) table_別名 order by id desc

三、技巧

1、1=1，1=2的使用，在SQL語句組合時用的較多

“where 1=1” 是表示選擇全部   “where 1=2”全部不選，
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 

我們可以直接寫成
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+@strWhere 

2、收縮資料庫
--重建索引
DBCC REINDEX
DBCC INDEXDEFRAG
--收縮資料和日誌
DBCC SHRINKDB
DBCC SHRINKFILE

3、壓縮資料庫
dbcc shrinkdatabase(dbname)

4、轉移資料庫給新使用者以已存在使用者許可權
exec sp_change_users_login 'update_one','newname','oldname'
go

5、檢查備份集
RESTORE VERIFYONLY from disk='E:\dvbbs.bak'

6、修復資料庫
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、日誌清除
SET NOCOUNT ON
DECLARE @LogicalFileName sysname,
        @MaxMinutes INT,
        @NewSize INT

USE     tablename             -- 要操作的資料庫名
SELECT  @LogicalFileName = 'tablename_log',  -- 日誌檔名
@MaxMinutes = 10,               -- Limit on time allowed to wrap log.
        @NewSize = 1                  -- 你想設定的日誌檔案的大小(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')  
        DELETE DummyTrans
        SELECT @Counter = @Counter + 1
      END   
    EXEC (@TruncLog)  
  END   
SELECT 'Final Size of ' + db_name() + ' LOG is ' +
        CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 
        CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
  FROM sysfiles 
  WHERE name = @LogicalFileName
DROP TABLE DummyTrans
SET NOCOUNT OFF 

8、說明：更改某個表
exec sp_changeobjectowner 'tablename','dbo'

9、儲存更改全部表

CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
 @OldOwner as NVARCHAR(128),
 @NewOwner as NVARCHAR(128)
AS

DECLARE @Name   as NVARCHAR(128)
DECLARE @Owner  as NVARCHAR(128)
DECLARE @OwnerName  as NVARCHAR(128)

DECLARE curObject CURSOR FOR 
 select 'Name'   = name,
  'Owner'   = user_name(uid)
 from sysobjects
 where user_name(uid)=@OldOwner
 order by name

OPEN  curObject
FETCH NEXT FROM curObject INTO @Name, @Owner
WHILE(@@FETCH_STATUS=0)
BEGIN     
 if @Owner=@OldOwner 
 begin
  set @OwnerName = @OldOwner + '.' + rtrim(@Name)
  exec sp_changeobjectowner @OwnerName, @NewOwner
 end
-- select @name,@NewOwner,@OldOwner

 FETCH NEXT FROM curObject INTO @Name, @Owner
END

close curObject
deallocate curObject
GO

10、SQL SERVER中直接迴圈寫入資料
declare @i int
set @i=1
while @i<30
begin
   insert into test (userid) values(@i)
   set @i=@i+1
end