SQL語句參考,包含Access、MySQL 以及 SQL Serversql
CREATE DATABASE database-name
drop database dbname
建立 備份數據的 device數據庫
USE master EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat'
開始 備份express
BACKUP DATABASE pubs TO testBack
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
A:create table tab_new like tab_old (使用舊錶建立新表) B:create table tab_new as select col1,col2… from tab_old definition only
drop table tabname
Alter table tabname add column col type 注:列增長後將不能刪除。DB2中列加上後數據類型也不能改變,惟一能改變的是增長varchar類型的長度。
Alter table tabname add primary key(col)
Alter table tabname drop primary key(col)
create [unique] index idxname on tabname(col….)
drop index idxname 注:索引是不可更改的,想更改必須刪除從新建。
create view viewname as select statement
drop view viewname
選擇:select * from table1 where 範圍 插入:insert into table1(field1,field2) values(value1,value2) 刪除:delete from table1 where 範圍 更新:update table1 set field1=value1 where 範圍 查找:select * from table1 where field1 like ’%value1%’ ---like的語法很精妙,查資料! 排序:select * from table1 order by field1,field2 [desc] 總數:select count as totalcount from table1 求和:select sum(field1) as sumvalue from table1 平均:select avg(field1) as avgvalue from table1 最大:select max(field1) as maxvalue from table1 最小:select min(field1) as minvalue from table1
UNION 運算符經過組合其餘兩個結果表(例如 TABLE1 和 TABLE2)並消去表中任何重複行而派生出一個結果表。當 ALL 隨 UNION一塊兒使用時(即 UNION ALL),不消除重複行。兩種狀況下,派生表的每一行不是來自 TABLE1 就是來自 TABLE2。
EXCEPT 運算符經過包括全部在 TABLE1 中但不在 TABLE2 中的行並消除全部重複行而派生出一個結果表。當 ALL 隨 EXCEPT 一塊兒使用時 (EXCEPT ALL),不消除重複行。
INTERSECT 運算符經過只包括 TABLE1 和 TABLE2 中都有的行並消除全部重複行而派生出一個結果表。當 ALL 隨 INTERSECT 一塊兒使用時 (INTERSECT ALL),不消除重複行。
注:使用運算詞的幾個查詢結果行必須是一致的。服務器
左外鏈接(左鏈接):結果集幾包括鏈接表的匹配行,也包括左鏈接表的全部行。網絡
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
右外鏈接(右鏈接):結果集既包括鏈接表的匹配鏈接行,也包括右鏈接表的全部行。ide
全外鏈接:不只包括符號鏈接表的匹配行,還包括兩個鏈接表中的全部記錄。函數
一張表,一旦分組 完成後,查詢後只能獲得組相關的信息。
組相關的信息:(統計信息) count,sum,max,min,avg 分組的標準)
在SQLServer中分組時:不能以text,ntext,image類型的字段做爲分組依據
在selecte統計函數中的字段,不能和普通的字段放在一塊兒;oop
分離數據庫: sp_detach_db;
附加數據庫:sp_attach_db 後接代表,附加須要完整的路徑名性能
sp_renamedb 'old_name', 'new_name'
insert into b(a, b, c) select d,e,f from b;
insert into b(a, b, c) select d,e,f from b in ‘具體數據庫’ where 條件
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)
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) 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
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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
select * from table1 where a [not] in (‘值1’,’值2’,’值4’,’值6’)
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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 .....
SQL: select * from 日程安排 where datediff('minute',f開始時間,getdate())>5
select top 10 b.* from (select top 20 主鍵字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主鍵字段 = a.主鍵字段 order by a.排序字段
具體實現:ui
關於數據庫分頁:
declare @start int,@end int @sql nvarchar(600) set @sql=’select top’+str(@end-@start+1)+’+from T where rid not in(select top’+str(@str-1)+’Rid from T where Rid>-1)’ exec sp_executesql @sql
注意:在top後不能直接跟一個變量,因此在實際應用中只有這樣的進行特殊的處理。Rid爲一個標識列,若是top後還有具體的字段,這樣作是很是有好處的。由於這樣能夠避免 top的字段若是是邏輯索引的,查詢的結果後實際表中的不一致(邏輯索引中的數據有可能和數據表中的不一致,而查詢時若是處在索引則首先查詢索引)
select top 10 * form table1 where 範圍
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
(select a from tableA ) except (select a from tableB) except (select a from tableC)
select top 10 * from tablename order by newid()
select newid()
1),delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2),select distinct * into temp from tablename delete from tablename insert into tablename select * from temp 評價: 這種操做牽連大量的數據的移動,這種作法不適合大容量的數據操做 3),例如:在一個外部表中導入數據,因爲某些緣由第一次只導入了一部分,但很難判斷具體位置,這樣只有在下一次所有導入,這樣也就產生好多重複的字段,怎樣刪除重複字段 alter table tablename --添加一個自增列 add column_b int identity(1,1) delete from tablename where column_b not in( select max(column_b) from tablename group by column1,column2,...) alter table tablename drop column column_b
select name from sysobjects where type='U' // U表明用戶
select name from syscolumns where id=object_id('TableName')
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
TRUNCATE TABLE table1
select top 5 * from (select top 15 * from table order by id asc) table_別名 order by id desc
「where 1=1」 是表示選擇所有 「where 1=2」所有不選,
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
咱們能夠直接寫成
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 and '+ @strWhere
--重建索引 DBCC REINDEX DBCC INDEXDEFRAG --收縮數據和日誌 DBCC SHRINKDB DBCC SHRINKFILE
dbcc shrinkdatabase(dbname)
exec sp_change_users_login 'update_one','newname','oldname' go
RESTORE VERIFYONLY from disk='E:\dvbbs.bak'
ALTER DATABASE [dvbbs] SET SINGLE_USER GO DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK GO ALTER DATABASE [dvbbs] SET MULTI_USER GO
SET NOCOUNT ON DECLARE @LogicalFileName sysname, @MaxMinutes INT, @NewSize INT USE tablename -- 要操做的數據庫名 SELECT @LogicalFileName = 'tablename_log', -- 日誌文件名 @MaxMinutes = 10, -- Limit on time allowed to wrap log. @NewSize = 1 -- 你想設定的日誌文件的大小(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') 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
exec sp_changeobjectowner 'tablename','dbo'
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
declare @i int set @i=1 while @i<30 begin insert into test (userid) values(@i) set @i=@i+1 end
案例:
有以下表,要求就裱中全部沒有及格的成績,在每次增長0.1的基礎上,使他們剛好及格:
Name score
Zhangshan 80
Lishi 59
Wangwu 50
Songquan 69
while((select min(score) from tb_table)<60) begin update tb_table set score =score*1.01 where score<60 if (select min(score) from tb_table)>60 break else continue end
Select * From TableName Order By CustomerName Collate Chinese_PRC_Stroke_ci_as //從少到多
select encrypt('原始密碼') select pwdencrypt('原始密碼') select pwdcompare('原始密碼','加密後密碼') = 1--相同;不然不相同 encrypt('原始密碼') select pwdencrypt('原始密碼') select pwdcompare('原始密碼','加密後密碼') = 1--相同;不然不相同
declare @list varchar(1000), @sql nvarchar(1000) select @list=@list+','+b.name from sysobjects a,syscolumns b where a.id=b.id and a.name='表A' set @sql='select '+right(@list,len(@list)-1)+' from 表A' exec (@sql)
EXEC master..xp_fixeddrives
if (select checksum_agg(binary_checksum(*)) from A) = (select checksum_agg(binary_checksum(*)) from B) print '相等' else print '不相等'
DECLARE hcforeach CURSOR GLOBAL FOR SELECT 'kill '+RTRIM(spid) FROM master.dbo.sysprocesses WHERE program_name IN('SQL profiler',N'SQL 事件探查器') EXEC sp_msforeach_worker '?'
開頭到N條記錄
Select Top N * From 表
N到M條記錄(要有主索引ID)
Select Top M-N * From 表 Where ID in (Select Top M ID From 表) Order by ID Desc
N到結尾記錄
Select Top N * From 表 Order by ID Desc
案例
例如1:一張表有一萬多條記錄,表的第一個字段 RecID 是自增加字段, 寫一個SQL語句, 找出表的第31到第40個記錄。
select top 10 recid from A where recid not in(select top 30 recid from A)
分析:若是這樣寫會產生某些問題,若是recid在表中存在邏輯索引。
select top 10 recid from A where……是從索引中查找,然後面的select top 30 recid from A則在數據表中查找,這樣因爲索引中的順序有可能和數據表中的不一致,這樣就致使查詢到的不是原本的欲獲得的數據。
解決方案
1, 用order by select top 30 recid from A order by ricid 若是該字段不是自增加,就會出現問題
2, 在那個子查詢中也加條件:select top 30 recid from A where recid>-1
例2:查詢表中的最後以條記錄,並不知道這個表共有多少數據,以及表結構。
set @s = ‘select top 1 * from T where pid not in (select top ’ + str(@count-1) + ’ pid from T)’
print @s exec sp_executesql @s
select Name from sysobjects where xtype='u' and status>=0
select name from syscolumns where id=object_id('表名') select name from syscolumns where id in (select id from sysobjects where type = 'u' and name = '表名')
兩種方式的效果相同
select a.* from sysobjects a, syscomments b where a.id = b.id and b.text like '%表名%'
select name as 存儲過程名稱 from sysobjects where xtype='P'
select * from master..sysdatabases D where sid not in(select sid from master..syslogins where name='sa') 或者 select dbid, name AS DB_NAME from master..sysdatabases where sid <> 0x01
select column_name,data_type from information_schema.columns where table_name = '表名'
--建立連接服務器 exec sp_addlinkedserver 'ITSV ', ' ', 'SQLOLEDB ', '遠程服務器名或ip地址 ' exec sp_addlinkedsrvlogin 'ITSV ', 'false ',null, '用戶名 ', '密碼 ' --查詢示例 select * from ITSV.數據庫名.dbo.表名 --導入示例 select * into 表 from ITSV.數據庫名.dbo.表名 --之後再也不使用時刪除連接服務器 exec sp_dropserver 'ITSV ', 'droplogins ' --鏈接遠程/局域網數據(openrowset/openquery/opendatasource) --一、openrowset --查詢示例 select * from openrowset( 'SQLOLEDB ', 'sql服務器名 '; '用戶名 '; '密碼 ',數據庫名.dbo.表名) --生成本地表 select * into 表 from openrowset( 'SQLOLEDB ', 'sql服務器名 '; '用戶名 '; '密碼 ',數據庫名.dbo.表名) --把本地表導入遠程表 insert openrowset( 'SQLOLEDB ', 'sql服務器名 '; '用戶名 '; '密碼 ',數據庫名.dbo.表名) select *from 本地表 --更新本地表 update b set b.列A=a.列A from openrowset( 'SQLOLEDB ', 'sql服務器名 '; '用戶名 '; '密碼 ',數據庫名.dbo.表名)as a inner join 本地表 b on a.column1=b.column1 --openquery用法須要建立一個鏈接 --首先建立一個鏈接建立連接服務器 exec sp_addlinkedserver 'ITSV ', ' ', 'SQLOLEDB ', '遠程服務器名或ip地址 ' --查詢 select * FROM openquery(ITSV, 'SELECT * FROM 數據庫.dbo.表名 ') --把本地表導入遠程表 insert openquery(ITSV, 'SELECT * FROM 數據庫.dbo.表名 ') select * from 本地表 --更新本地表 update b set b.列B=a.列B FROM openquery(ITSV, 'SELECT * FROM 數據庫.dbo.表名 ') as a inner join 本地表 b on a.列A=b.列A --三、opendatasource/openrowset SELECT * FROM opendatasource( 'SQLOLEDB ', 'Data Source=ip/ServerName;User ID=登錄名;Password=密碼 ' ).test.dbo.roy_ta --把本地表導入遠程表 insert opendatasource( 'SQLOLEDB ', 'Data Source=ip/ServerName;User ID=登錄名;Password=密碼 ').數據庫.dbo.表名 select * from 本地表
SQL Server基本函數
長度與分析用