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。 "{xrL4BtC
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一、基础 S@tLCqV4
1、说明:创建数据库 ^
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CREATE DATABASE database-name #%2rP'He
2、说明:删除数据库 5;WH:XM
drop database dbname ;;t yoh~t
3、说明:备份sql server (,2SXV
--- 创建 备份数据的 device h"W,WxL8
USE master A{zN| S[
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' /}Axf"OE
--- 开始 备份 |-ALklXr
BACKUP DATABASE pubs TO testBack Rv>-4@fMJ
4、说明:创建新表 t}4,]ms
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Yh7t"=o
根据已有的表创建新表: ,qwuLBW
A:create table tab_new like tab_old (使用旧表创建新表) Dy&i&5E.-l
B:create table tab_new as select col1,col2... from tab_old definition only ATyEf5Id_
5、说明:删除新表 lVa%$F{Pq
drop table tabname j;r-NCBnz
6、说明:增加一个列 {Xy5pfW
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Alter table tabname add column col type 4_lrg|X1
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 1I6px$^E\
7、说明:添加主键: Alter table tabname add primary key(col) Y@iS_lR
说明:删除主键: Alter table tabname drop primary key(col) .Hm>i
8、说明:创建索引:create [unique] index idxname on tabname(col....) >:!5*E5?
删除索引:drop index idxname /nsX]V6i
注:索引是不可更改的,想更改必须删除重新建。 pki%vRY
9、说明:创建视图:create view viewname as select statement r5/0u(\LB
删除视图:drop view viewname FV!q!D
10、说明:几个简单的基本的sql语句 ^\% (,KNo
选择:select * from table1 where 范围 8,%^
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插入:insert into table1(field1,field2) values(value1,value2) gJ{)-\
删除:delete from table1 where 范围 ;(%QD
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更新:update table1 set field1=value1 where 范围 Ax@$+/Z!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ~~P5k:
排序:select * from table1 order by field1,field2 [desc] kTB0b*V
总数:select count as totalcount from table1 Zx@a/jLO[n
求和:select sum(field1) as sumvalue from table1 5DZ#9m/
平均:select avg(field1) as avgvalue from table1 gD?l-RT>
最大:select max(field1) as maxvalue from table1 uW{l(}0N
最小:select min(field1) as minvalue from table1 .<FH>NW)
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11、说明:几个高级查询运算词 |df Pki{
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A: UNION 运算符 BxmWIItz
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 3d]S!=4H"
B: EXCEPT 运算符 J8(lIk:e
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 &z3o7rif$
C: INTERSECT 运算符 J@'wf8Ub
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。 "S]TP$O D
注:使用运算词的几个查询结果行必须是一致的。 )&O
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12、说明:使用外连接 CRE3icXbQ
A、left outer join: 'H!Uh]!
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 BU_nh+dF
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c AT3Mlz~7#
B:right outer join: tNI^@xdim1
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 X_h}J=33Q
C:full outer join: LL!Dx%JZ
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 8<.Oq4ku
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二、提升 q9_OGd|P
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "8MF_Gu):
法一:select * into b from a where 1<>1 \8cx6 G'
法二:select top 0 * into b from a VA5xp]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) CCx&7f
insert into b(a, b, c) select d,e,f from b; aFYIM`?(
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) r19
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 h]gp ^?=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. n>YKa)|W`
4、说明:子查询(表名1:a 表名2:b) NLqzi%s
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) a=2%4Wmz
5、说明:显示文章、提交人和最后回复时间 ##*3bDf$-5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b KRzAy)8
6、说明:外连接查询(表名1:a 表名2:b) Yq
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c %u'ukcL7
7、说明:在线视图查询(表名1:a ) 6&x@.1('z
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7:1Lol-V
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 c@7rqHU-0
select * from table1 where time between time1 and time2 p5iuYHKk?
select a,b,c, from table1 where a not between 数值1 and 数值2 &QgR*,5eo
9、说明:in 的使用方法 Rm( "=(
select * from table1 where a [not] in ('值1','值2','值4','值6') }7Q% 6&IR
10、说明:两张关联表,删除主表中已经在副表中没有的信息 5b*C1HS@X
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 8ib:FF(= u
11、说明:四表联查问题: a~w$#fo"`f
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 ..... L8B!u9%
12、说明:日程安排提前五分钟提醒 K|,
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1+s;FJ2}
13、说明:一条sql 语句搞定数据库分页 sgFEK[w.y
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 k,*XG$2h
14、说明:前10条记录 mzgfFNm^G)
select top 10 * form table1 where 范围 Zy/_
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ;=z:F<Y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @ 6vIap|
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 W<g1<z\f
(select a from tableA ) except (select a from tableB) except (select a from tableC) fJg+ Ryo
17、说明:随机取出10条数据 H:|uw
select top 10 * from tablename order by newid() 9'B `]/L
18、说明:随机选择记录 |BXg/gW
select newid() Dd|VMW=
19、说明:删除重复记录 2^7`mES
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) h376Be{P
20、说明:列出数据库里所有的表名 <hyKu
select name from sysobjects where type='U' /{I$ #:M
21、说明:列出表里的所有的 a7opCmL
select name from syscolumns where id=object_id('TableName') l/5
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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。 [/r(__.
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 `a/`,N
显示结果: ^2rN>k,?
type vender pcs yG{TH0tq
电脑 A 1 E1
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电脑 A 1 ih3n<gXF
光盘 B 2 SXh-A1t
光盘 A 2 wCBplaojJ
手机 B 3 :ws<-Qy
手机 C 3 At;LO9T3z
23、说明:初始化表table1 }SZd
TRUNCATE TABLE table1 3v-~K)hl?
24、说明:选择从10到15的记录 Vurqt_nb
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %cn<ych
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三、技巧 KI.hy2?e
1、1=1,1=2的使用,在SQL语句组合时用的较多 vY3h3o
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n@3>6_^rwT
如: Q>z8IlJ}
if @strWhere !='' .}+}8[p4l
begin *-X[u:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %BODkc Zh
end UiNP3TJ'L
else "[N!m1i:{
begin ;tf=gdX;
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' DY*N|OnqJ
end EU#^7
我们可以直接写成 %C]>9."
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Fr-SvsNFB
2、收缩数据库 7tp36 TE
--重建索引 3so%gvY.'
DBCC REINDEX l]SX@zTb
DBCC INDEXDEFRAG j~MI<I+l[
--收缩数据和日志 WIGi51yC.x
DBCC SHRINKDB rJB}qYD
DBCC SHRINKFILE /dHF6yW
3、压缩数据库 /bmN\I
dbcc shrinkdatabase(dbname) a+QpM*n7Lq
4、转移数据库给新用户以已存在用户权限 !,PWb3S
exec sp_change_users_login 'update_one','newname','oldname' j>kqz>3
go '3;b@g,
5、检查备份集 q^nVN#
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' W,u:gzmhw
6、修复数据库 wd6owr
ALTER DATABASE [dvbbs] SET SINGLE_USER q3`u1S7Z7
GO %so]L+r2!
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wL[
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GO +7}]E1Uf
ALTER DATABASE [dvbbs] SET MULTI_USER V]^$S"Tv
GO HaYo!.(Fv
7、日志清除 ;*J
SET NOCOUNT ON xSu >
DECLARE @LogicalFileName sysname, ,r}6iFu
@MaxMinutes INT, 5V-I1B&
@NewSize INT wIgS3K
USE tablename -- 要操作的数据库名 Bw.i}3UT6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4p wH>1
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 73-p*o(pt
@NewSize = 1 -- 你想设定的日志文件的大小(M) q(w(Sd)#L
-- Setup / initialize X>^fEQq"
DECLARE @OriginalSize int "N#Y gSr
SELECT @OriginalSize = size O.M1@w]
FROM sysfiles 6u%&<")4HP
WHERE name = @LogicalFileName 4M T 7 `sr
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |j|rS5
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Gw` L"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' '"Nr, vQo
FROM sysfiles gGuO
WHERE name = @LogicalFileName naNghGQ
CREATE TABLE DummyTrans
!@sUj
(DummyColumn char (8000) not null) CJyevMf'
DECLARE @Counter INT, +[ZY:ZQ
@StartTime DATETIME, #9s,#
}
@TruncLog VARCHAR(255) 18Emi<&A
SELECT @StartTime = GETDATE(), e+|sSp A
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' p<%d2@lp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4ppz,L,4
EXEC (@TruncLog) \U0'P;em
-- Wrap the log if necessary. E{@[k%,_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired "M0z(NkH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) qgB_=Q#E
AND (@OriginalSize * 8 /1024) > @NewSize 9H~n_
BEGIN -- Outer loop. -g<oS9
SELECT @Counter = 0 n+p }\msH
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &&%H%9
BEGIN -- update 9M ]_nP Y
INSERT DummyTrans VALUES ('Fill Log') VN.Je:Ju
DELETE DummyTrans =MWHJ'3-/
SELECT @Counter = @Counter + 1 }B^tL$k
END g2]Qv@nxw
EXEC (@TruncLog) u@444Vzg
END `@%LzeGz
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ` %}RNC
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + -RLOD\ZBh
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 4e
FROM sysfiles y>LBl]
WHERE name = @LogicalFileName @+DX.9
DROP TABLE DummyTrans ,)io5nZF
SET NOCOUNT OFF 5twhm
8、说明:更改某个表 F[MFx^sT{
exec sp_changeobjectowner 'tablename','dbo' MfkZ
9、存储更改全部表 T>>c2$ x
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _dU\JD
@OldOwner as NVARCHAR(128), Xc.`-J~Il
@NewOwner as NVARCHAR(128) {G-kNU
AS afk>+4q
DECLARE @Name as NVARCHAR(128) 4!$"ayGv;D
DECLARE @Owner as NVARCHAR(128) zeRyL3fnmb
DECLARE @OwnerName as NVARCHAR(128) m+9#5a-
DECLARE curObject CURSOR FOR @]0%L0u
select 'Name' = name, (%9$! v{3
'Owner' = user_name(uid) 0 {mex4
from sysobjects k=^xVQuI
where user_name(uid)=@OldOwner ?cZlN!
order by name 1x^GWtRp
OPEN curObject !m$jk2<
FETCH NEXT FROM curObject INTO @Name, @Owner ,,TnIouy
WHILE(@@FETCH_STATUS=0) V)4J`xg^
BEGIN 4K74=r),i
if @Owner=@OldOwner *ui</+
begin x^CS"v7
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Wl4%GB
exec sp_changeobjectowner @OwnerName, @NewOwner ?ubro0F:
end 5-M-X#(
-- select @name,@NewOwner,@OldOwner '>"
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FETCH NEXT FROM curObject INTO @Name, @Owner ^@]3R QB
END `mqMLo*
close curObject \NC3'G:Ii
deallocate curObject Mihg:
GO >3bCTE
10、SQL SERVER中直接循环写入数据 ,?3G;-
declare @i int E"0>yl)
set @i=1 GthYzd:'hJ
while @i<30 8>V5dEbx'
begin Ts9uL5i
insert into test (userid) values(@i) I:.s_8mH}
set @i=@i+1 %znc##j)q
end Dh*n!7lD`
小记存储过程中经常用到的本周,本月,本年函数 e(yh[7p=
Dateadd(wk,datediff(wk,0,getdate()),-1) _*zt=zn>
Dateadd(wk,datediff(wk,0,getdate()),6) SAz
Dateadd(mm,datediff(mm,0,getdate()),0) OJxl<Q=z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }\LQ3y"[
Dateadd(yy,datediff(yy,0,getdate()),0) f 1d?.)
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0))
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上面的SQL代码只是一个时间段 g78^9Y*1
Dateadd(wk,datediff(wk,0,getdate()),-1) E.f%H(b
Dateadd(wk,datediff(wk,0,getdate()),6) Ep}s}Stlr}
就是表示本周时间段. uw7zWJ
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下面的SQL的条件部分,就是查询时间段在本周范围内的: nP$9CA
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ElXFeJ%[G
而在存储过程中 s @C}P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) =Sv/IXX\di
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y}H!c;