SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 ;L ^o*`
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一、基础 !&@615Vtw
1、说明:创建数据库 [AJJSd/:
CREATE DATABASE database-name !^G\9"4A
2、说明:删除数据库 <<O$ G7c
drop database dbname SOaoo^,O
3、说明:备份sql server zX i'kB
--- 创建 备份数据的 device )NT*bLRPQ
USE master sU^1wB
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' EU Fa5C:
--- 开始 备份 {Qj~M<@3
BACKUP DATABASE pubs TO testBack 0jWVp-y
4、说明:创建新表 b"
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) k4zZ7H
根据已有的表创建新表: VuZr:-K/
A:create table tab_new like tab_old (使用旧表创建新表) ,|/f`Pl
B:create table tab_new as select col1,col2... from tab_old definition only yEy6]f+>+
5、说明:删除新表 86a\+Kz%%L
drop table tabname <9b&<K:
6、说明:增加一个列 P[fq8lDA
Alter table tabname add column col type wVtwx0|1
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 4s
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7、说明:添加主键: Alter table tabname add primary key(col) G=bCNn<
说明:删除主键: Alter table tabname drop primary key(col) ?+8\.a!
8、说明:创建索引:create [unique] index idxname on tabname(col....) .*Qx\,
删除索引:drop index idxname z\4.Gm-
注:索引是不可更改的,想更改必须删除重新建。 j B{8u&kz)
9、说明:创建视图:create view viewname as select statement <wHP2|<l*
删除视图:drop view viewname :[d9tm
10、说明:几个简单的基本的sql语句 u)Whr@m
选择:select * from table1 where 范围 WTiD[u
插入:insert into table1(field1,field2) values(value1,value2) <%mRSv
删除:delete from table1 where 范围 RT8 ?7xFc
更新:update table1 set field1=value1 where 范围 ,<X9 Y2B
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7a}k
排序:select * from table1 order by field1,field2 [desc] 2st3
总数:select count as totalcount from table1 b\,+f n
求和:select sum(field1) as sumvalue from table1 ?Z} &EH
平均:select avg(field1) as avgvalue from table1 dDGQ`+H9
最大:select max(field1) as maxvalue from table1 JK]PRDyD
最小:select min(field1) as minvalue from table1 62NsJ<#>
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11、说明:几个高级查询运算词 tQ601H>o
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A: UNION 运算符 0tJZ4(0
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 3__-nV
B: EXCEPT 运算符 o#N+Y?O
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 wdoR%b{M
C: INTERSECT 运算符 f?)-}\[IR{
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 "uf%iJ:%
注:使用运算词的几个查询结果行必须是一致的。 [_:nHZb
12、说明:使用外连接 {\\Tgs
A、left outer join: O33`+UV"W
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 2+WaA,
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 Gp\
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B:right outer join: IvNT6]6 P
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 (QiAisE
C:full outer join: ,tRj4mx
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ,]/X\t5]D
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二、提升 IUct
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >5
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法一:select * into b from a where 1<>1 EEL,^3KR
法二:select top 0 * into b from a .o}v#W+st
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {7pli{`
insert into b(a, b, c) select d,e,f from b; y~HP>~Oh
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用)
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 XB5DPx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. FE;x8(;W8
4、说明:子查询(表名1:a 表名2:b) NyuQMU
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) J?$,c4;W2
5、说明:显示文章、提交人和最后回复时间 [a<SDMR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b AwF:Iu^3n
6、说明:外连接查询(表名1:a 表名2:b) \lNN Msd&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c kAGBdaJ"
7、说明:在线视图查询(表名1:a ) rU(+T0t?I
select * from (SELECT a,b,c FROM a) T where t.a > 1; Uoix
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 3irl
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select * from table1 where time between time1 and time2 Ssg&QI
select a,b,c, from table1 where a not between 数值1 and 数值2 p{dj~ &v
9、说明:in 的使用方法 Oa>Ppldeg
select * from table1 where a [not] in ('值1','值2','值4','值6') _h1mF<\ X^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Srd4))2/0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]
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11、说明:四表联查问题: E&:,oG2M
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ZSm3 XXk
12、说明:日程安排提前五分钟提醒 k$}fWR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +x}<IS8
13、说明:一条sql 语句搞定数据库分页 Jj%K=sw
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 iDrZc
14、说明:前10条记录 Ny)X+2Ae
select top 10 * form table1 where 范围 Z;)%%V%o
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) jb!i$/%w
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [z9Z5sLO
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 0+b1vhQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7"D.L-H
17、说明:随机取出10条数据 -d:Jta!}{
select top 10 * from tablename order by newid() Pj%|\kbNs
18、说明:随机选择记录 8, >P
select newid() 0#^v{DC
19、说明:删除重复记录 hP&Bt
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) U:_^#\p
20、说明:列出数据库里所有的表名 IIx#2r
select name from sysobjects where type='U' sCHJ&>m5-
21、说明:列出表里的所有的 ` sU/& P
select name from syscolumns where id=object_id('TableName') FzC'G57Kl
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ;sFF+^~L
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type P7/X|M z
显示结果: |P}y,pNQ
type vender pcs z2>lI9D4V
电脑 A 1 JqiP>4Uwm^
电脑 A 1 VyGJ=[ ]
光盘 B 2 q> C'BIr
光盘 A 2 *CHX
手机 B 3 45>?o
手机 C 3 [!OxZ!
23、说明:初始化表table1 H<N,%G
TRUNCATE TABLE table1 #>+ HlT
24、说明:选择从10到15的记录 cYt!n5w~W
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]OzUGXxo~
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三、技巧 d6 5L!4
1、1=1,1=2的使用,在SQL语句组合时用的较多 5XBH$&Td
"where 1=1" 是表示选择全部 "where 1=2"全部不选, V "h
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如: ')3
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if @strWhere !='' CeC6hGR5
begin 6NHX2Ja
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere wAW5
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end @MCg%Afw
else D d</`iUq
begin [hj6N*4y
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' w+CA1q<
end oILZgNe'
我们可以直接写成 B`J~^+`[*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @I!0-OjL
2、收缩数据库 3/n5#&c\4
--重建索引 N<injx
DBCC REINDEX 9-*uPK]m9
DBCC INDEXDEFRAG |#
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--收缩数据和日志 k+pr \d ~
DBCC SHRINKDB 6 ~w@PRy
DBCC SHRINKFILE 9;-p'C
3、压缩数据库
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dbcc shrinkdatabase(dbname) SI-Ops~e
4、转移数据库给新用户以已存在用户权限 .OY`Z)SS%
exec sp_change_users_login 'update_one','newname','oldname' s,&Z=zt0R
go |8tilOqI
5、检查备份集 _zi|
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .ctw2x5W
6、修复数据库 E09:E
ALTER DATABASE [dvbbs] SET SINGLE_USER 5]Y?m'
GO SKsKPqz
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK HCC#j9UN6
GO JrRH\+4K
ALTER DATABASE [dvbbs] SET MULTI_USER u5f9Jw}
GO 'AS|ZRr/
7、日志清除 k_nql8H
SET NOCOUNT ON I(BQ34q
DECLARE @LogicalFileName sysname, U#WF;q0L
@MaxMinutes INT, zue~ce73J
@NewSize INT X?qK0fS
USE tablename -- 要操作的数据库名 68WO~*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 lp%pbx43s
@MaxMinutes = 10, -- Limit on time allowed to wrap log. sN01rtB(UT
@NewSize = 1 -- 你想设定的日志文件的大小(M)
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-- Setup / initialize $C$V%5aA
DECLARE @OriginalSize int K^<BW(s
SELECT @OriginalSize = size pJ'"j 6Q
FROM sysfiles 9Y_HyOZ*GX
WHERE name = @LogicalFileName @O^6&\s>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + >V8-i`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *d4eK+U$5
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S k\K4
FROM sysfiles VY=jc~c]v
WHERE name = @LogicalFileName 5f K_Aq{
CREATE TABLE DummyTrans = x)-u8P
(DummyColumn char (8000) not null) EaY?aAuS:
DECLARE @Counter INT, >$/>#e~
@StartTime DATETIME, ]Wlco
@TruncLog VARCHAR(255) C7ScS"~
SELECT @StartTime = GETDATE(), qHlQ+:n
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' rlSeu5X6
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =wV<hg)C
EXEC (@TruncLog) 4yr'W8X_
-- Wrap the log if necessary. =|y9UlsD
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired `%"\@<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) xHLlMn4M
AND (@OriginalSize * 8 /1024) > @NewSize bI9~jWgGp
BEGIN -- Outer loop. ag;pN*z
SELECT @Counter = 0 kxIF#/8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) hT&Y#fh
BEGIN -- update 2E)-M9ds
INSERT DummyTrans VALUES ('Fill Log') ~t~k2^)|"
DELETE DummyTrans U,{eHe ?>T
SELECT @Counter = @Counter + 1 Ee%%d
END \aUC(K~o\;
EXEC (@TruncLog) aa/(N7
END K+K#+RBK
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ?(F6#"/E
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + j[G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k&vz7Q`T
FROM sysfiles cj|80$cSA
WHERE name = @LogicalFileName DGn;m\B
DROP TABLE DummyTrans Vl=l?A8
SET NOCOUNT OFF -4IE]'##
8、说明:更改某个表 e>7>j@(K]
exec sp_changeobjectowner 'tablename','dbo' }t=!(GOb}
9、存储更改全部表 b;W3j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1N#|
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@OldOwner as NVARCHAR(128), )|R)Q6UJ
@NewOwner as NVARCHAR(128) N&+x+;Kx
AS U!?_W=?
DECLARE @Name as NVARCHAR(128) 6"5A%{J
DECLARE @Owner as NVARCHAR(128) v,{
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DECLARE @OwnerName as NVARCHAR(128) rIu$pZO
DECLARE curObject CURSOR FOR RSyUaA
select 'Name' = name, %G/hD
'Owner' = user_name(uid) .* ?wF
from sysobjects Kp~VS<3
where user_name(uid)=@OldOwner M2>Vj/
order by name b"uu
OPEN curObject "ESwA
FETCH NEXT FROM curObject INTO @Name, @Owner vkx7paY_
WHILE(@@FETCH_STATUS=0) ~Z?TFg
BEGIN t~EPn.
if @Owner=@OldOwner b_#m}yZ6
begin p;59?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Hz1%x
exec sp_changeobjectowner @OwnerName, @NewOwner rJT^H5!o"
end r6MMCJ|G
-- select @name,@NewOwner,@OldOwner V6&!9b
FETCH NEXT FROM curObject INTO @Name, @Owner L_uVL#To
END U9:zVy
close curObject o WrKM
deallocate curObject n.`($yR_
GO J6s`'gFns
10、SQL SERVER中直接循环写入数据 QT<
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declare @i int <ro7vPKNa
set @i=1 ['X]R:3h
while @i<30 Pmr5S4Ka
begin -aPg#ub
insert into test (userid) values(@i) j9x<Y]
set @i=@i+1 HZzD VCU
end xd q?/^E
小记存储过程中经常用到的本周,本月,本年函数 \:# L)
Dateadd(wk,datediff(wk,0,getdate()),-1) fo*2:?K&
Dateadd(wk,datediff(wk,0,getdate()),6) w(*vj
Dateadd(mm,datediff(mm,0,getdate()),0) c)TPM/>(p
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) LEbB(x;@
Dateadd(yy,datediff(yy,0,getdate()),0) JgKO|VO
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) =w_Ype`
上面的SQL代码只是一个时间段 c?f4Q,%|
Dateadd(wk,datediff(wk,0,getdate()),-1) $k@O`xD,q
Dateadd(wk,datediff(wk,0,getdate()),6) 25nt14Y0u
就是表示本周时间段. G\/zkrxmv
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~ drS} V
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~rE|%o
而在存储过程中 *KZYv=s,u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) =V,mtT
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) -j#2}[J7