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。 uG>nV
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一、基础 #X.+
1、说明:创建数据库 ~DLIz g7p!
CREATE DATABASE database-name oj}"H>tTp
2、说明:删除数据库 _eLVBG35z
drop database dbname HBLWOQab
3、说明:备份sql server zzvlI66e
--- 创建 备份数据的 device AV @\ +0
USE master %B EC]
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9e<Zgr?N
--- 开始 备份 ][Y^-Ak1
BACKUP DATABASE pubs TO testBack SvK1.NUa
4、说明:创建新表 ke/_k/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) W'_/6_c$!
根据已有的表创建新表: GoE#Mxh xo
A:create table tab_new like tab_old (使用旧表创建新表) Su8'$CFz$.
B:create table tab_new as select col1,col2... from tab_old definition only v5T9Y-{`
5、说明:删除新表 u9![6$R
drop table tabname LD+f'^>>Z
6、说明:增加一个列 gZ(O)uzv
Alter table tabname add column col type W81o"TR|pt
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。 .R5/8VuHF
7、说明:添加主键: Alter table tabname add primary key(col) NMjnL&P`
说明:删除主键: Alter table tabname drop primary key(col) 015Owi
8、说明:创建索引:create [unique] index idxname on tabname(col....) jeDlH6X'
删除索引:drop index idxname yBz>0I3
注:索引是不可更改的,想更改必须删除重新建。 2H&{1f\Bf
9、说明:创建视图:create view viewname as select statement p27p~b&
删除视图:drop view viewname |*Ot/TvG
10、说明:几个简单的基本的sql语句 7o{*Z
选择:select * from table1 where 范围 "@/ba!L+
插入:insert into table1(field1,field2) values(value1,value2) ]Sta]}VQ
删除:delete from table1 where 范围 Bt>}LLBS2
更新:update table1 set field1=value1 where 范围 DY><qk
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =aow
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排序:select * from table1 order by field1,field2 [desc] oA3d^%(c
总数:select count as totalcount from table1 Mr6E/7g%
求和:select sum(field1) as sumvalue from table1 a@|.;#FF
平均:select avg(field1) as avgvalue from table1 \;
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最大:select max(field1) as maxvalue from table1 g'G8 3F
最小:select min(field1) as minvalue from table1 3kLOoL?
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11、说明:几个高级查询运算词 "d?f:x3v^
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A: UNION 运算符 >.Q0Tx!P
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。 ?~qC,N [
B: EXCEPT 运算符 rh $1-Y
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 R^9"N?Q7;`
C: INTERSECT 运算符 ,o&<WMD
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 11*"d#
注:使用运算词的几个查询结果行必须是一致的。 |h1^Gv
12、说明:使用外连接 tL8't]M,
A、left outer join: spiDm:Xe
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 P$h;SK
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 yv${M u
B:right outer join: 0^>E`/
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。 v:P!(`sF
C:full outer join: hCLk#_
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。 TczXHT}G
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二、提升 fI[dhd6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A*Q[k 9B
法一:select * into b from a where 1<>1
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法二:select top 0 * into b from a z1vni'%J
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) S 1ibw \'
insert into b(a, b, c) select d,e,f from b; ,iOZ|
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) 'aPCb`^;w
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 gY\mXM*^
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Ak|b0l>^
4、说明:子查询(表名1:a 表名2:b) UQdyv(jXq
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) n49s3|#)G
5、说明:显示文章、提交人和最后回复时间 >PH< N
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b t/LgHb:)
6、说明:外连接查询(表名1:a 表名2:b) 7sN0`7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c w?;b7i
7、说明:在线视图查询(表名1:a ) 1OPfRDn.bk
select * from (SELECT a,b,c FROM a) T where t.a > 1; 8g5.7{ky
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 [Ye5Y?
select * from table1 where time between time1 and time2 ~D!ESe*=
select a,b,c, from table1 where a not between 数值1 and 数值2 (qk5f`O
9、说明:in 的使用方法 F25<+1kr
select * from table1 where a [not] in ('值1','值2','值4','值6') sVD([`Nmc
10、说明:两张关联表,删除主表中已经在副表中没有的信息 i -V0Lm/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -t b;igv
11、说明:四表联查问题: /T#o<D
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 ..... o?=fhc
12、说明:日程安排提前五分钟提醒 cV(H<"I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]84YvpfW
13、说明:一条sql 语句搞定数据库分页 7`+UB>8
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 -~0'a
14、说明:前10条记录 C!kbZTO[p"
select top 10 * form table1 where 范围 iXnx1w
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.) #?5VsD8
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /~"AG l.
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 '7=<#Blc
(select a from tableA ) except (select a from tableB) except (select a from tableC) U:Fpj~E_w
17、说明:随机取出10条数据 &0h=4i=6r
select top 10 * from tablename order by newid() j5A\y^Kv
18、说明:随机选择记录 }amE6
select newid() *hl<Y,W(
19、说明:删除重复记录 ,m"l\jP
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) " V/k<HRw
20、说明:列出数据库里所有的表名 _6/Qp`s
select name from sysobjects where type='U' a~F u
21、说明:列出表里的所有的 R''Sfz>8
select name from syscolumns where id=object_id('TableName') ;>'SV~F
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。 P ]_Vz
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 mlmnkgl
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显示结果: h?3f5G*&H
type vender pcs t.u{.P\Md\
电脑 A 1 fIlIH
电脑 A 1 `v<f}
光盘 B 2 3V!W@[ }:
光盘 A 2 `O jvt-5}E
手机 B 3 J
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手机 C 3 n_ OUWvs
23、说明:初始化表table1 o+R. u}|
TRUNCATE TABLE table1 1dXh\r_n
24、说明:选择从10到15的记录 {vCU^BN,k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V?o&])?[
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三、技巧 ),z,LU Yf
1、1=1,1=2的使用,在SQL语句组合时用的较多 8*"rZh}'
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r$Kh3EEF`E
如: ],!pp3U
if @strWhere !='' gZ~y}@Ly
begin 1gL8$.B?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere vatx+)
end )/i4YLO
else X ^9t
begin mrX}\p
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' [29$~.m$Y
end CcbWW4 )
我们可以直接写成 !/[AQ{**T!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y}*Ctdrl
2、收缩数据库 s')!<E+z\t
--重建索引 \y<+Fac1S
DBCC REINDEX `~sf}S
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DBCC INDEXDEFRAG KF*B
--收缩数据和日志 d9ZDpzxB
DBCC SHRINKDB 7=AO^:=bx
DBCC SHRINKFILE xU:PhhS
3、压缩数据库 :s? y,
dbcc shrinkdatabase(dbname) ((n5';|N
4、转移数据库给新用户以已存在用户权限 Y'\3ux0]4'
exec sp_change_users_login 'update_one','newname','oldname' o(vZ*^\
go mq>*W'M
5、检查备份集 -_:JQ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' YL_!#<k@
6、修复数据库 VK"[=l
ALTER DATABASE [dvbbs] SET SINGLE_USER dVK@Fgo
GO b49|4
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &xF4p,7
GO %pQdq[J={
ALTER DATABASE [dvbbs] SET MULTI_USER CAcOWwDm
GO AJdlqbd'+
7、日志清除 q|m#IVc
SET NOCOUNT ON 0R.Gjz*Q
DECLARE @LogicalFileName sysname, ntd
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@MaxMinutes INT, `=WzG"
@NewSize INT c|8KT
USE tablename -- 要操作的数据库名 P1vF{e
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~0:$G?fz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *NKC\aV`0
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y>c5:F;
-- Setup / initialize 0`zm>fh}
DECLARE @OriginalSize int JB: mbH
SELECT @OriginalSize = size
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FROM sysfiles a?f5(qW3
WHERE name = @LogicalFileName mk$Yoz
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X*D5y8<
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Z.Lx^h+U
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rl_1),J\qG
FROM sysfiles +X4ttv
WHERE name = @LogicalFileName =t <:zLe
CREATE TABLE DummyTrans n$A(6]z5O
(DummyColumn char (8000) not null) Vz+=ZK r5
DECLARE @Counter INT, =D;UMSf
@StartTime DATETIME, C]{V%jU
@TruncLog VARCHAR(255) y^vfgP<@
SELECT @StartTime = GETDATE(), Qt)7mf
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' t~udfOvY
DBCC SHRINKFILE (@LogicalFileName, @NewSize) H znI R
EXEC (@TruncLog) qugPs(uQ
-- Wrap the log if necessary. -bIpmp?
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired f^>lObvd
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) UwzE'#Q-
AND (@OriginalSize * 8 /1024) > @NewSize X_EC:GU
BEGIN -- Outer loop. =[43y%
SELECT @Counter = 0 ahz@HX
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "fX8xZdS
BEGIN -- update g@N=N
INSERT DummyTrans VALUES ('Fill Log') <'+R%6
DELETE DummyTrans fM
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SELECT @Counter = @Counter + 1 co(fGp#!
END 2t~7eI%d
EXEC (@TruncLog) )yz9? ]a
END J_)z:`[yE
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !S$oaCxM
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ve')LY<
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9X*eE
FROM sysfiles P"[l86:
WHERE name = @LogicalFileName ) J:'5hz
DROP TABLE DummyTrans Uz m[e%/`
SET NOCOUNT OFF )x5$io
8、说明:更改某个表 "m\UqQGX
exec sp_changeobjectowner 'tablename','dbo' lMI
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9、存储更改全部表 d(dw]6I6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch B "s8i{Vm
@OldOwner as NVARCHAR(128), @[Jt~v
@NewOwner as NVARCHAR(128) u"CIPc{Sr
AS 4YB7og%P
DECLARE @Name as NVARCHAR(128) 2TevdyI
DECLARE @Owner as NVARCHAR(128) Cvu8X&y
DECLARE @OwnerName as NVARCHAR(128) U3dR[*
DECLARE curObject CURSOR FOR ^FyvaO
select 'Name' = name, R*c0NJF
'Owner' = user_name(uid) IQIb\OUo!v
from sysobjects
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where user_name(uid)=@OldOwner bx%hizb
order by name `U?H^,FVA
OPEN curObject 9lazo
FETCH NEXT FROM curObject INTO @Name, @Owner #uDBF
WHILE(@@FETCH_STATUS=0) D ;T r
BEGIN FZ'>LZ
if @Owner=@OldOwner PY3Vu]zD
begin \c@qtIc
set @OwnerName = @OldOwner + '.' + rtrim(@Name) cq+M
*1;
exec sp_changeobjectowner @OwnerName, @NewOwner |SXMu_w
end [laL6
-- select @name,@NewOwner,@OldOwner WRU@i;l
FETCH NEXT FROM curObject INTO @Name, @Owner ,BN}H-W\2
END t&?v9n"X
close curObject C">=2OO
deallocate curObject =-B3vd:LF
GO Ot:\h
10、SQL SERVER中直接循环写入数据 U*Q5ff7M6"
declare @i int r~BQy'
set @i=1 a[{QlD^D
while @i<30 7>e~i,
begin Y=wP3q
insert into test (userid) values(@i) @_weMz8}
set @i=@i+1 c75vAKZ2
end 3YNkT"~T
小记存储过程中经常用到的本周,本月,本年函数 Y.hH
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Dateadd(wk,datediff(wk,0,getdate()),-1) U"R.!=v
Dateadd(wk,datediff(wk,0,getdate()),6) RAkFgC~
Dateadd(mm,datediff(mm,0,getdate()),0) k:uuJ|
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) TB3T:A>2
Dateadd(yy,datediff(yy,0,getdate()),0) ~uD;_Y=u)r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7g<`wLAH
上面的SQL代码只是一个时间段 Wg;TXs/
Dateadd(wk,datediff(wk,0,getdate()),-1) $vicHuX!
Dateadd(wk,datediff(wk,0,getdate()),6) PQI,vr'R
就是表示本周时间段. b42pLbpe'E
下面的SQL的条件部分,就是查询时间段在本周范围内的: N?<@o2{
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8GAQVe^$-
而在存储过程中
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) QbKYB
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) aw@Aoq