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。 FZ9<Q
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一、基础 j''Iai_
1、说明:创建数据库 ?iX=2-
CREATE DATABASE database-name /;rN/ot2o
2、说明:删除数据库 4l''/$P
drop database dbname
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3、说明:备份sql server AD\<}/3U
--- 创建 备份数据的 device .Y|\7%(
USE master V,+[XB
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' tFaE cP
--- 开始 备份 .( h$@|Y
BACKUP DATABASE pubs TO testBack {^W,e ^:
4、说明:创建新表 \.c
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) XijLS7Aw|
根据已有的表创建新表: V]]qu:Mh8
A:create table tab_new like tab_old (使用旧表创建新表) |T_Pz&-
B:create table tab_new as select col1,col2... from tab_old definition only @vYmkF`
5、说明:删除新表 YfwJBzD
drop table tabname 0s|LK
6、说明:增加一个列 Qs9 U&*L
Alter table tabname add column col type rk/
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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。 X u):.0I
7、说明:添加主键: Alter table tabname add primary key(col) dz|*n'd
说明:删除主键: Alter table tabname drop primary key(col) $NT9LtT@K
8、说明:创建索引:create [unique] index idxname on tabname(col....) i)L:VkN
删除索引:drop index idxname pRvs;klf
注:索引是不可更改的,想更改必须删除重新建。 =
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9、说明:创建视图:create view viewname as select statement ?@?a}
删除视图:drop view viewname el?V2v[
10、说明:几个简单的基本的sql语句 }+4Bf+u:
选择:select * from table1 where 范围 &a_kJ)J
插入:insert into table1(field1,field2) values(value1,value2) cN7z(I0[
删除:delete from table1 where 范围 ;q; C^l
更新:update table1 set field1=value1 where 范围 8-a6Q|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! uX +<`3O
排序:select * from table1 order by field1,field2 [desc] 6I.m c
总数:select count as totalcount from table1 \83A|+k
求和:select sum(field1) as sumvalue from table1 ^|GtO.
平均:select avg(field1) as avgvalue from table1 n2mw@Ay!
最大:select max(field1) as maxvalue from table1 ms7 7{A3
最小:select min(field1) as minvalue from table1 %^=!s
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11、说明:几个高级查询运算词 =Rx?6%
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A: UNION 运算符 4E-A@FR
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。 *ZR@z80i
B: EXCEPT 运算符 &}0wzcMg
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。 TucAs0-bF
C: INTERSECT 运算符 4)HWPX
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。 P"h\7V,d%
注:使用运算词的几个查询结果行必须是一致的。 .'b3iG&
12、说明:使用外连接
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A、left outer join: O^Vy"8Ji}y
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。 Tn0l|GRuZA
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 n&m?BuG
B:right outer join: |3:=qpT-
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。 > &vO4L
C:full outer join: $U1kP?pR
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Ws*PMK.0
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二、提升 \678Nx
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e( o/we{
法一:select * into b from a where 1<>1 y3nm!tjyM
法二:select top 0 * into b from a C^" Hj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) O)xEF~DaD
insert into b(a, b, c) select d,e,f from b; 6IY}SI0N
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) tnF9Vj[#%_
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mvA xx`jc
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. *:T>~ilF
4、说明:子查询(表名1:a 表名2:b) s`iNbW="
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) cL)rjty2
5、说明:显示文章、提交人和最后回复时间 c =N]!
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b bEQtVe@`
6、说明:外连接查询(表名1:a 表名2:b) j]B$(pt
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c boF4d'g"
7、说明:在线视图查询(表名1:a ) {9Mdt`WL
select * from (SELECT a,b,c FROM a) T where t.a > 1; C6'*/wq
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 8gtCY~m
select * from table1 where time between time1 and time2 3.<6;?
select a,b,c, from table1 where a not between 数值1 and 数值2 kE_@5t7O{
9、说明:in 的使用方法 HS`bto0*
select * from table1 where a [not] in ('值1','值2','值4','值6') i9\\evJs
10、说明:两张关联表,删除主表中已经在副表中没有的信息 12d}#G<q-
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ^s@*ISY
11、说明:四表联查问题: :uwRuPI
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 ..... mrhp)yF
12、说明:日程安排提前五分钟提醒 5Vqmv<F;$Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *[xNp[4EU
13、说明:一条sql 语句搞定数据库分页 ;WS7.
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 QR5,_wJ&
14、说明:前10条记录 (>LHj]}K
select top 10 * form table1 where 范围 sMfFm@\ N
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.) K"k"ml<4E
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ]PzTl {]
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 y/}VtD
(select a from tableA ) except (select a from tableB) except (select a from tableC) c_z/At;4
17、说明:随机取出10条数据 {|5$1v
select top 10 * from tablename order by newid() ?]\W8)
18、说明:随机选择记录 < k+fKl
select newid() L`\`NNQC
19、说明:删除重复记录 *mQDS.'AB@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Wl !!5\
20、说明:列出数据库里所有的表名 QFNz9c
select name from sysobjects where type='U' ^?6
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21、说明:列出表里的所有的 t$y&=v
select name from syscolumns where id=object_id('TableName') q3x;_y^
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。 Q}Ze-JIL$
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 Ie2w0Cs28
显示结果: .hQ3A"
type vender pcs CFBUQMl>
电脑 A 1 [)H,zpl
电脑 A 1 Vgqvvq<S
光盘 B 2 Y-%l7GErhL
光盘 A 2 xV,4U/T
手机 B 3 c#n4zdQd]5
手机 C 3 Y*kh$E%<#
23、说明:初始化表table1 qXU:A-IdIl
TRUNCATE TABLE table1 Z9"{f)T
24、说明:选择从10到15的记录 -yl4tW
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KO-Zz&2f
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三、技巧 tIxhSI^
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~"JE![XR
"where 1=1" 是表示选择全部 "where 1=2"全部不选, npO@Haw
如: i9&K
if @strWhere !='' Ho )t=qn
begin &N/|(<CB
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~^rey
end dT hn?
else d^Zo35X
begin u+mjguIv
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Q$?7) yyu+
end 7cUR.PI#Q
我们可以直接写成 G>=9gSLM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere s<Ex"+
2、收缩数据库 Ms:KM{T0
--重建索引 5w,lw
DBCC REINDEX #JL&]Z+X6
DBCC INDEXDEFRAG _'!N q
--收缩数据和日志 L876$
DBCC SHRINKDB l$k]O
DBCC SHRINKFILE vLv|SqD
3、压缩数据库 IW1GhZ41'
dbcc shrinkdatabase(dbname) 1A%N0#_(Md
4、转移数据库给新用户以已存在用户权限 79{.O`v
exec sp_change_users_login 'update_one','newname','oldname' MPKpS3VS
go ~j/bCMEf!
5、检查备份集 XlPK3^'N)h
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <pTQpU
6、修复数据库 er["NSo
ALTER DATABASE [dvbbs] SET SINGLE_USER ~^lH ^J
GO 4i_spF-3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK MiSja#"+A
GO ]5} -y3
ALTER DATABASE [dvbbs] SET MULTI_USER }g>dn
GO 9tzoris[~
7、日志清除 nd $H
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SET NOCOUNT ON LN@E\wRw{r
DECLARE @LogicalFileName sysname, aW0u8Dz
@MaxMinutes INT, -Q<z1vz
@NewSize INT t(J![wB}
USE tablename -- 要操作的数据库名 0Y5LDP
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +={
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *F\T}k7
@NewSize = 1 -- 你想设定的日志文件的大小(M) mJ0}DJiX$
-- Setup / initialize x[vpoB+c
DECLARE @OriginalSize int g(-;_j!=
SELECT @OriginalSize = size IvEMg2f}
FROM sysfiles 2YL`3cgfb
WHERE name = @LogicalFileName 94~"U5oQ:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4*0:bhhhf_
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "XGD:>Q.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' vnz[w=U
FROM sysfiles r+t ,J|V
WHERE name = @LogicalFileName |rr$U
CREATE TABLE DummyTrans "bD+/\ z
(DummyColumn char (8000) not null) @T<ad7g-2J
DECLARE @Counter INT, A#v|@sul
@StartTime DATETIME, opm?':Qst
@TruncLog VARCHAR(255) E|HSwTHe
SELECT @StartTime = GETDATE(), 9U#\nXM
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Z{Vxr*9oO
DBCC SHRINKFILE (@LogicalFileName, @NewSize) +dqk6RE
EXEC (@TruncLog) OZ(Dpx(Q
-- Wrap the log if necessary. a$ C2}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Ho|o,XvLv
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) N7e`6d!
AND (@OriginalSize * 8 /1024) > @NewSize <\ y!3;
BEGIN -- Outer loop. k0H?9Z4k5
SELECT @Counter = 0 NFB*1_m
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6N9 c<JC
BEGIN -- update b->eg 8|
INSERT DummyTrans VALUES ('Fill Log') 1pd 9s8CA
DELETE DummyTrans lemVP'cn
SELECT @Counter = @Counter + 1 pTcbq
END h7bPAW=(
EXEC (@TruncLog) EfFz7j&X
END Yuwc$Qp)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~c9>Nr9|`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + j(0Ilx|7v
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' v2Dt3$@H6
FROM sysfiles uzHT.iBn
WHERE name = @LogicalFileName YSqv86
DROP TABLE DummyTrans w?kGi>7E
SET NOCOUNT OFF [dl+:P:zc
8、说明:更改某个表 F(d:t!
exec sp_changeobjectowner 'tablename','dbo' PXV)NC
9、存储更改全部表 mfZ)^X
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]kRI}Om2
@OldOwner as NVARCHAR(128), 8$\Za,)g
@NewOwner as NVARCHAR(128) 6tOCZ'f
AS ?Fce!J
DECLARE @Name as NVARCHAR(128) RTK}mhnV
DECLARE @Owner as NVARCHAR(128) $[[?;g
DECLARE @OwnerName as NVARCHAR(128) lwVk(l
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DECLARE curObject CURSOR FOR i*X{^A73"
select 'Name' = name, Y^QKp"
'Owner' = user_name(uid) ]53O}sH>
from sysobjects F7\BF
where user_name(uid)=@OldOwner '9 'l=Sh
order by name gXLCRn!iR
OPEN curObject A'GlCp
FETCH NEXT FROM curObject INTO @Name, @Owner 5gSylts8
WHILE(@@FETCH_STATUS=0) {1jpLdCbV^
BEGIN vwVVBG;t
if @Owner=@OldOwner :d.1;st
begin <O.Kqk*
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) <x0)7xX
exec sp_changeobjectowner @OwnerName, @NewOwner tE[H8
end 4avc=Y5
-- select @name,@NewOwner,@OldOwner %Ys$@dB
FETCH NEXT FROM curObject INTO @Name, @Owner `AR"!X
END b 8>q;
close curObject gc##V]OD
deallocate curObject t\zbEN
GO u+m4!`
10、SQL SERVER中直接循环写入数据 ZT6V/MD7T.
declare @i int 0x\2#i
set @i=1 cg,Ua!c
while @i<30 @@Q6TB
begin (z/jMMms
insert into test (userid) values(@i) j?xk&
set @i=@i+1 Zb."*zL
end U2bzUxK
小记存储过程中经常用到的本周,本月,本年函数 f27)v(EJ
Dateadd(wk,datediff(wk,0,getdate()),-1) k=?^){[We
Dateadd(wk,datediff(wk,0,getdate()),6) Jn=42Q:>
Dateadd(mm,datediff(mm,0,getdate()),0) \]I
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 8"x9#kyU<3
Dateadd(yy,datediff(yy,0,getdate()),0) A#(`9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ur6e&bTp
上面的SQL代码只是一个时间段 bw9
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Dateadd(wk,datediff(wk,0,getdate()),-1) ]BfS270
Dateadd(wk,datediff(wk,0,getdate()),6) -^Xy%
就是表示本周时间段. -j&Vtr
下面的SQL的条件部分,就是查询时间段在本周范围内的: .Rvf/-e
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8.yCA
而在存储过程中 c_#*mA"+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1fY>>*oP
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ><=rIhG%H@