1、說明:創(chuàng)建數(shù)據(jù)庫 CREATE DATABASE database-name 2、說明:刪除數(shù)據(jù)庫 drop database dbname3、說明:備份sql server --- 創(chuàng)建 備份數(shù)據(jù)的 device USE master EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' --- 開始 備份 BACKUP DATABASE pubs TO testBack 4、說明:創(chuàng)建新表 create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
根據(jù)已有的表創(chuàng)建新表: A:create table tab_new like tab_old (使用舊表創(chuàng)建新表) B:create table tab_new as select col1,col2… from tab_old definition only5、說明:刪除新表 drop table tabname 6、說明:增加一個(gè)列 Alter table tabname add column col type注:列增加后將不能刪除。DB2中列加上后數(shù)據(jù)類型也不能改變,唯一能改變的是增加varchar類型的長度。 7、說明:添加主鍵: Alter table tabname add primary key(col) 說明:刪除主鍵: Alter table tabname drop primary key(col) 8、說明:創(chuàng)建索引:create [unique] index idxname on tabname(col….) 刪除索引:drop index idxname 注:索引是不可更改的,想更改必須刪除重新建。 9、說明:創(chuàng)建視圖:create view viewname as select statement 刪除視圖:drop view viewname 10、說明:幾個(gè)簡單的基本的sql語句 選擇:select * from table1 where 范圍 插入:insert into table1(field1,field2) values(value1,value2) 刪除:delete from table1 where 范圍更新:update table1 set field1=value1 where 范圍 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(shù):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 11、說明:幾個(gè)高級(jí)查詢運(yùn)算詞 A: UNION 運(yùn)算符 UNION 運(yùn)算符通過組合其他兩個(gè)結(jié)果表(例如 TABLE1 和 TABLE2)并消去表中任何重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL 隨 UNION 一起使用時(shí)(即 UNION ALL),不消除重復(fù)行。兩種情況下,派生表的每一行不是來自 TABLE1 就是來自 TABLE2。 B:EXCEPT 運(yùn)算符 EXCEPT運(yùn)算符通過包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL 隨 EXCEPT 一起使用時(shí) (EXCEPT ALL),不消除重復(fù)行。 C:INTERSECT 運(yùn)算符 INTERSECT運(yùn)算符通過只包括 TABLE1 和 TABLE2 中都有的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表。當(dāng) ALL隨 INTERSECT 一起使用時(shí) (INTERSECT ALL),不消除重復(fù)行。 注:使用運(yùn)算詞的幾個(gè)查詢結(jié)果行必須是一致的。 12、說明:使用外連接 A、left (outer) join: 左外連接(左連接):結(jié)果集幾包括連接表的匹配行,也包括左連接表的所有行。 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 B:right (outer) join: 右外連接(右連接):結(jié)果集既包括連接表的匹配連接行,也包括右連接表的所有行。 C:full/cross (outer) join: 全外連接:不僅包括符號(hào)連接表的匹配行,還包括兩個(gè)連接表中的所有記錄。 12、分組:Group by: 一張表,一旦分組 完成后,查詢后只能得到組相關(guān)的信息。 組相關(guān)的信息:(統(tǒng)計(jì)信息) count,sum,max,min,avg 分組的標(biāo)準(zhǔn)) 在SQLServer中分組時(shí):不能以text,ntext,image類型的字段作為分組依據(jù) 在selecte統(tǒng)計(jì)函數(shù)中的字段,不能和普通的字段放在一起;
1、說明:復(fù)制表(只復(fù)制結(jié)構(gòu),源表名:a 新表名:b) (Access可用) 法一:select * into b from a where 1<>1(僅用于SQlServer)法二:select top 0 * into b from a 2、說明:拷貝表(拷貝數(shù)據(jù),源表名:a 目標(biāo)表名:b) (Access可用) insert into b(a, b, c) select d,e,f from b;
3、說明:跨數(shù)據(jù)庫之間表的拷貝(具體數(shù)據(jù)使用絕對(duì)路徑) (Access可用) insert into b(a, b, c) select d,e,f from b in ‘具體數(shù)據(jù)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、提交人和最后回復(fù)時(shí)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:外連接查詢(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:在線視圖查詢(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限制查詢數(shù)據(jù)范圍時(shí)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(shù)值1 and 數(shù)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(guān)聯(lián)表,刪除主表中已經(jīng)在副表中沒有的信息 delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
11、說明:四表聯(lián)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(shí)間,getdate())>5
13、說明:一條sql 語句搞定數(shù)據(jù)庫分頁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(shí)現(xiàn):關(guān)于數(shù)據(jù)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)’
15、說明:選擇在每一組b值相同的數(shù)據(jù)中對(duì)應(yīng)的a最大的記錄的所有信息(類似這樣的用法可以用于論壇每月排行榜,每月熱銷產(chǎn)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中的行并消除所有重復(fù)行而派生出一個(gè)結(jié)果表 (select a from tableA ) except (select a from tableB) except (select a from tableC)
17、說明:隨機(jī)取出10條數(shù)據(jù) select top 10 * from tablename order by newid()
18、說明:隨機(jī)選擇記錄 select newid()
19、說明:刪除重復(fù)記錄 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(píng)價(jià):這種操作牽連大量的數(shù)據(jù)的移動(dòng),這種做法不適合大容量但數(shù)據(jù)操作3),例如:在一個(gè)外部表中導(dǎo)入數(shù)據(jù),由于某些原因第一次只導(dǎo)入了一部分,但很難判斷具體位置,這樣只有在下一次全部導(dǎo)入,這樣也就產(chǎn)生好多重復(fù)的字段,怎樣刪除重復(fù)字段
alter table tablename --添加一個(gè)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
20、說明:列出數(shù)據(jù)庫里所有的表名 select name from sysobjects where type='U' // U代表用戶
21、說明:列出表里的所有的列名 select name from syscolumns where id=object_id('TableName')
22、說明:列示type、vender、pcs字段,以type字段排列,case可以方便地實(shí)現(xiàn)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(jié)果: type vender pcs 電腦 A 1 電腦 A 1 光盤 B 2 光盤 A 2 手機(jī) B 3 手機(jī) 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(shí)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
錯(cuò)誤!未找到目錄項(xiàng)。 set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2、收縮數(shù)據(jù)庫 --重建索引 DBCC REINDEX DBCC INDEXDEFRAG --收縮數(shù)據(jù)和日志 DBCC SHRINKDB DBCC SHRINKFILE
3、壓縮數(shù)據(jù)庫 dbcc shrinkdatabase(dbname)
4、轉(zhuǎn)移數(shù)據(jù)庫給新用戶以已存在用戶權(quán)限 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(fù)數(shù)據(jù)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、日志清除 SET NOCOUNT ON DECLARE @LogicalFileName sysname, @MaxMinutes INT, @NewSize INT
USE tablename -- 要操作的數(shù)據(jù)庫名 SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @MaxMinutes = 10, -- Limit on time allowed to wrap log. @NewSize = 1 -- 你想設(shè)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)
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
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中直接循環(huán)寫入數(shù)據(jù) declare @i int set @i=1 while @i<30 begin insert into test (userid) values(@i) set @i=@i+1 end 案例: 有如下表,要求就裱中所有沒有及格的成績,在每次增長0.1的基礎(chǔ)上,使他們剛好及格:
Name score
Zhangshan80
Lishi 59
Wangwu 50
Songquan69
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
數(shù)據(jù)開發(fā)-經(jīng)典
1.按姓氏筆畫排序: Select * From TableName Order By CustomerName Collate Chinese_PRC_Stroke_ci_as //從少到多
3.取回表中字段: 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)
4.查看硬盤分區(qū): EXEC master..xp_fixeddrives
5.比較A,B表是否相等: if (select checksum_agg(binary_checksum(*)) from A) = (select checksum_agg(binary_checksum(*)) from B) print '相等' else print '不相等'
6.殺掉所有的事件探察器進(jìn)程: 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 '?'
7.記錄搜索: 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(jié)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(gè)字段 RecID 是自增長字段, 寫一個(gè)SQL語句, 找出表的第31到第40個(gè)記錄。
select top 10 recid from A where recid not in(select top 30 recid from A)
分析:如果這樣寫會(huì)產(chǎn)生某些問題,如果recid在表中存在邏輯索引。
select top 10 recid from A where……是從索引中查找,而后面的select top 30 recid from A則在數(shù)據(jù)表中查找,這樣由于索引中的順序有可能和數(shù)據(jù)表中的不一致,這樣就導(dǎo)致查詢到的不是本來的欲得到的數(shù)據(jù)。
解決方案
1,用order by select top 30 recid from A order by ricid 如果該字段不是自增長,就會(huì)出現(xiàn)問題
2,在那個(gè)子查詢中也加條件:select top 30 recid from A where recid>-1
例2:查詢表中的最后以條記錄,并不知道這個(gè)表共有多少數(shù)據(jù),以及表結(jié)構(gòu)。 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
9:獲取當(dāng)前數(shù)據(jù)庫中的所有用戶表 select Name from sysobjects where xtype='u' and status>=0
10:獲取某一個(gè)表的所有字段 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
11:查看與某一個(gè)表相關(guān)的視圖、存儲(chǔ)過程、函數(shù)select a.* from sysobjects a, syscomments b where a.id = b.id and b.text like '%表名%'
12:查看當(dāng)前數(shù)據(jù)庫中所有存儲(chǔ)過程 select name as 存儲(chǔ)過程名稱 from sysobjects where xtype='P'
13:查詢用戶創(chuàng)建的所有數(shù)據(jù)庫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
14:查詢某一個(gè)表的字段和數(shù)據(jù)類型 select column_name,data_type from information_schema.columns where table_name = '表名'