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。 9T*v9d
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一、基础 {qN 5MsY
1、说明:创建数据库 %'X[^W
CREATE DATABASE database-name D"a~#^
2、说明:删除数据库 |v({-*7
drop database dbname /!3@]xz*
3、说明:备份sql server PEW=@xj2y
--- 创建 备份数据的 device 'LE=6{#
USE master }n4V|f-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' LILQ\I<<'
--- 开始 备份 #g]vc_V
BACKUP DATABASE pubs TO testBack `0Oh_8"
4、说明:创建新表 "$2y-|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) n:{qC{D-qS
根据已有的表创建新表: 'coV^~qy
A:create table tab_new like tab_old (使用旧表创建新表) pLLGus+W
B:create table tab_new as select col1,col2... from tab_old definition only Bi
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5、说明:删除新表 @
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drop table tabname n6BQk2l
6、说明:增加一个列 Y\$ySvZ0
Alter table tabname add column col type Ndi9FD3im
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 XBp? w
7、说明:添加主键: Alter table tabname add primary key(col) j'MO(ev
说明:删除主键: Alter table tabname drop primary key(col) &3n~%$#N
8、说明:创建索引:create [unique] index idxname on tabname(col....) HBu[gh;b
删除索引:drop index idxname ''0fF_P
注:索引是不可更改的,想更改必须删除重新建。 W7 #9jo
9、说明:创建视图:create view viewname as select statement p_${Nj
删除视图:drop view viewname =g|IG
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10、说明:几个简单的基本的sql语句 a- |*?{o
选择:select * from table1 where 范围 Y7*U:I+N
插入:insert into table1(field1,field2) values(value1,value2) C<m{*C-`a
删除:delete from table1 where 范围 .P7"e5ge
更新:update table1 set field1=value1 where 范围 (A~/ '0/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Z2'Bk2 L
排序:select * from table1 order by field1,field2 [desc] 1$p2}Bf{n
总数:select count as totalcount from table1 Q|D @Yd\
求和:select sum(field1) as sumvalue from table1 IVAmV!.z
平均:select avg(field1) as avgvalue from table1 =AEBeiz
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 $h*L=t(
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11、说明:几个高级查询运算词 )'6DNa[y
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A: UNION 运算符 FXi{87F2
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。 Jc|6&
B: EXCEPT 运算符 ]]oI#*c
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。 7aQc=^vaZ
C: INTERSECT 运算符 +h r@#n4A
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。 no9;<]4
注:使用运算词的几个查询结果行必须是一致的。 &GB:|I'%7
12、说明:使用外连接 WRrd'{sB
A、left outer join: )~HUo9K9
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。 k{Me[B
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 >o7n+Rb:
B:right outer join: 29?,<bB)
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。 3tZ]4ms}
C:full outer join: Cc%LztP>
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。 'gTb A?+@5
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二、提升 C'o64+W^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !3 f?:M
法一:select * into b from a where 1<>1 =[@zF9
法二:select top 0 * into b from a oaoU _V
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) / ;,Md,p
insert into b(a, b, c) select d,e,f from b; _YLfL
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) lna}@]oR
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /Q2mMSK1h
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4:dH]
4、说明:子查询(表名1:a 表名2:b) q&W[j5E
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) "3)4vuX@;c
5、说明:显示文章、提交人和最后回复时间 k=4N.*#`y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CkdP #}f
6、说明:外连接查询(表名1:a 表名2:b) ^7 &5
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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 Ipq"E
7、说明:在线视图查询(表名1:a ) uFPF!Ern
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7 D^gMN%p
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^4E
select * from table1 where time between time1 and time2 /M3Y~l$
select a,b,c, from table1 where a not between 数值1 and 数值2 /qy-qUh3h
9、说明:in 的使用方法 pJt,9e6
select * from table1 where a [not] in ('值1','值2','值4','值6') JSTuXW
10、说明:两张关联表,删除主表中已经在副表中没有的信息 O"c;|zCc>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) y6[If cN
11、说明:四表联查问题: |>tKq;/
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 ..... YYu6W@m]
12、说明:日程安排提前五分钟提醒 :qIXY/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 RkBb$q9F]
13、说明:一条sql 语句搞定数据库分页 V9dF1Hj
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 R)RG[F#
14、说明:前10条记录 PEuIWXr
select top 10 * form table1 where 范围 7,lq}a8z
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.) .[3Z1v,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) qx4I_%
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 LS88.w\=S@
(select a from tableA ) except (select a from tableB) except (select a from tableC) Zy(W^~NT
17、说明:随机取出10条数据 f v9V7
select top 10 * from tablename order by newid() Te}8!_ohyC
18、说明:随机选择记录 79xx2
select newid() EodQ*{l
19、说明:删除重复记录 '{V0M<O
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?Vf o+a,
20、说明:列出数据库里所有的表名 N=QfP
select name from sysobjects where type='U' Y!gCMLL
21、说明:列出表里的所有的 b7wvaRe.
select name from syscolumns where id=object_id('TableName') V&\[)D'c
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。 +(1zH-^.
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 )XzI
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显示结果: <\}KT*Xp
type vender pcs HP3lz,d
电脑 A 1 w6W}"Uw
电脑 A 1 /|eA9 ]
光盘 B 2 jg\Z;_!W
光盘 A 2 ZfgJ.<<
手机 B 3 N,;5{y1;J
手机 C 3 #EsNeBu
23、说明:初始化表table1 I$0)Px%z
TRUNCATE TABLE table1 ,Qnd3[2[
24、说明:选择从10到15的记录 Gch[Otq]%
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lo,$-bJ,<,
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三、技巧 |>JS!NM
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1、1=1,1=2的使用,在SQL语句组合时用的较多 Wu_kx2h
"where 1=1" 是表示选择全部 "where 1=2"全部不选, L"j
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如: < !dqTJos
if @strWhere !='' yRfSJbzaf\
begin KjE+QUa
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Y~(Md@!0S
end <c,u3cp
else 0Pe>Es|^A#
begin NF0%}II&xK
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' o)2W`i &
end )8UWhl=
我们可以直接写成 AbYqf%~7`l
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .On|uC)!
2、收缩数据库 5_z33,q2
--重建索引
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DBCC REINDEX ykX/9y+-s
DBCC INDEXDEFRAG naw0$kXTA
--收缩数据和日志 fI~Xmw+}}
DBCC SHRINKDB Ts ^"xlK
DBCC SHRINKFILE qh2ON>e;
3、压缩数据库 fmiz,$O4?
dbcc shrinkdatabase(dbname) A0q|J/T
4、转移数据库给新用户以已存在用户权限 E7Y`|nT
exec sp_change_users_login 'update_one','newname','oldname' uJ5Eka
go m:WyuU<
5、检查备份集 ,eZ1uBI?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' QiLEL
6、修复数据库 %d(^d
ALTER DATABASE [dvbbs] SET SINGLE_USER eQD)$d_5
GO Y>E zTV
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 'toa@5
GO nx^]>w
ALTER DATABASE [dvbbs] SET MULTI_USER B{C??g8/
GO n>^Y$yy}!
7、日志清除 PV4(hj
SET NOCOUNT ON 3+G@g#MY
DECLARE @LogicalFileName sysname, 8$ma;U d
@MaxMinutes INT, h0g:@ae%&
@NewSize INT $d)ca9
USE tablename -- 要操作的数据库名 l: <?{)N`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [-;_ZFS{
@MaxMinutes = 10, -- Limit on time allowed to wrap log. JNa"8
@NewSize = 1 -- 你想设定的日志文件的大小(M) 72Iy^Y[MX
-- Setup / initialize "Za>ZRR
DECLARE @OriginalSize int k=B]&F
SELECT @OriginalSize = size (jFGa2{
FROM sysfiles S<WdZ=8sA
WHERE name = @LogicalFileName SOi*SwQ8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + oNU0 qZ5
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + tdSfi<y5I
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ar:*oiU
FROM sysfiles !2'jrJGc
WHERE name = @LogicalFileName -sjd&)~S[
CREATE TABLE DummyTrans pm\x~3jHs
(DummyColumn char (8000) not null) -"h;uDz|z
DECLARE @Counter INT, !\"5rNy
@StartTime DATETIME, 4x;/HEb7?
@TruncLog VARCHAR(255) HaYE9/xS
SELECT @StartTime = GETDATE(), 2#<xAR
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %d>=+Ds[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) a(9L,v#?
EXEC (@TruncLog) A%D7bQ
-- Wrap the log if necessary. b r^_'1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired rZfN+S,g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)
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AND (@OriginalSize * 8 /1024) > @NewSize _/s(7y!
BEGIN -- Outer loop. Lv'D^'I
SELECT @Counter = 0 6C]1Q.f;
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) u9}1)9
BEGIN -- update B]Y}Hu
INSERT DummyTrans VALUES ('Fill Log') j^;I3_P
DELETE DummyTrans jGEt+\"/QJ
SELECT @Counter = @Counter + 1 D!.+Y-+Xzu
END P~G 1EK|4
EXEC (@TruncLog) Fx
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END f"9q^
SELECT 'Final Size of ' + db_name() + ' LOG is ' + oA =4=`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + qd#sY.|1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' W0k0$\iX
FROM sysfiles <0QH<4
WHERE name = @LogicalFileName =ZDAeVz3w
DROP TABLE DummyTrans sm\f0P!rv
SET NOCOUNT OFF F^5?\
8、说明:更改某个表 sp5eVAd
exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 8&Oa_{1+Q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch nD)K}4
@OldOwner as NVARCHAR(128), P4F3Dc
@NewOwner as NVARCHAR(128) {iv<w8CU)
AS l411a9o
DECLARE @Name as NVARCHAR(128) H~+ l7OhV
DECLARE @Owner as NVARCHAR(128) awOd_![c'
DECLARE @OwnerName as NVARCHAR(128) mFSw@CC
DECLARE curObject CURSOR FOR 0\:(ageY?
select 'Name' = name, H'LD}\K l
'Owner' = user_name(uid) j8fpj {hp
from sysobjects 0MkSf*
where user_name(uid)=@OldOwner ??i,Vr@)w
order by name Q<KvBgmT
OPEN curObject z j/!In
FETCH NEXT FROM curObject INTO @Name, @Owner EC\yzH*X
WHILE(@@FETCH_STATUS=0) T[sDVkCbxf
BEGIN Pp|*J^U 4
if @Owner=@OldOwner ;Wl+zw
begin *_KFW@bC:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,Vh{gm1
exec sp_changeobjectowner @OwnerName, @NewOwner 8S<@"v
end B?)@u|0
-- select @name,@NewOwner,@OldOwner raCi 8
FETCH NEXT FROM curObject INTO @Name, @Owner uFLx
END s.x&LG
close curObject L
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deallocate curObject {O,{c\
GO RtCkV xaEx
10、SQL SERVER中直接循环写入数据 sPps q
declare @i int 8Y_ol#\L
set @i=1 lr{?"tl_
while @i<30 ]\xy\\b/`
begin S3@|Q\*r
insert into test (userid) values(@i) qKE:3g35
set @i=@i+1 \igmv]G%
end w1Ec_y {
小记存储过程中经常用到的本周,本月,本年函数 +8#_59;x
Dateadd(wk,datediff(wk,0,getdate()),-1) %<\6TZr
Dateadd(wk,datediff(wk,0,getdate()),6) hTM[8 ~<^
Dateadd(mm,datediff(mm,0,getdate()),0) Udc=,yo3Qm
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) oXDN+4ge
Dateadd(yy,datediff(yy,0,getdate()),0) ,i0b)=!o
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k~/>b~.c
上面的SQL代码只是一个时间段 W0C@9&pn6
Dateadd(wk,datediff(wk,0,getdate()),-1) K^ 3co
Dateadd(wk,datediff(wk,0,getdate()),6) qBQ`~4s
就是表示本周时间段. `AkIK*
下面的SQL的条件部分,就是查询时间段在本周范围内的: Hzhceeh_+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) t2V0lyeL
而在存储过程中 I`w4Xrd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) JIFU;*PR1
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) u- o--q