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。 =,!\~`^
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一、基础 w@\vHH.;V
1、说明:创建数据库 !}+tdT(y
CREATE DATABASE database-name )+")Sz3zx
2、说明:删除数据库 dx*qb
drop database dbname iTh:N2/-vc
3、说明:备份sql server y)c5u%(
--- 创建 备份数据的 device "&Dx=Yf
USE master V==z"
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 5BkV aF7Th
--- 开始 备份 mV^Zy
BACKUP DATABASE pubs TO testBack OX:O^ (-r,
4、说明:创建新表 \qvaE+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ,bE$| x'
根据已有的表创建新表: mnk"Vr` L
A:create table tab_new like tab_old (使用旧表创建新表) @XD+' {]
B:create table tab_new as select col1,col2... from tab_old definition only ZI;<7tF_z
5、说明:删除新表 8;Fn7k_Uf
drop table tabname ^taBG3P
6、说明:增加一个列 4n1; Bh$
Alter table tabname add column col type D0(xNhmKz
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。 IPSF]"}~
7、说明:添加主键: Alter table tabname add primary key(col) )Rat0$6
说明:删除主键: Alter table tabname drop primary key(col) if;71ZE
8、说明:创建索引:create [unique] index idxname on tabname(col....) 0Z<I%<8bK
删除索引:drop index idxname 3cS2gxF
注:索引是不可更改的,想更改必须删除重新建。 Xd E`d.
9、说明:创建视图:create view viewname as select statement ;|p$\26S)%
删除视图:drop view viewname <!$:8ls
10、说明:几个简单的基本的sql语句 }0`nvAf
选择:select * from table1 where 范围 /N>e&e[35\
插入:insert into table1(field1,field2) values(value1,value2) I\?9+3 XnQ
删除:delete from table1 where 范围 yL^UE=#C_
更新:update table1 set field1=value1 where 范围 (C]
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "1q>At
排序:select * from table1 order by field1,field2 [desc] x6afI<dm
总数:select count as totalcount from table1 plu$h-$d
求和:select sum(field1) as sumvalue from table1 YJS{i
平均:select avg(field1) as avgvalue from table1 %B5r"=oO
最大:select max(field1) as maxvalue from table1 {HC@u{K-
最小:select min(field1) as minvalue from table1 5m=I*.qE
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11、说明:几个高级查询运算词 U`Jy!x2m
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A: UNION 运算符 \7MHaQvS
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ^[Ua46/" m
B: EXCEPT 运算符 z|7zj/+g
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ]Fvm 7V
C: INTERSECT 运算符 DcIvhB p
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 {u!)y?}I-
注:使用运算词的几个查询结果行必须是一致的。 LNl#h
12、说明:使用外连接 1C Pjil*eb
A、left outer join: rV({4cIe9R
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 kpbm4t
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6+V\t+aug
B:right outer join: S0g'r
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 wi8Yl1p]!z
C:full outer join: 2Nxm@B` {
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 <X TU8G
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二、提升 M@P1, Y
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'sp-%YlM -
法一:select * into b from a where 1<>1 4`Nt{
法二:select top 0 * into b from a
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "'^4*o9
insert into b(a, b, c) select d,e,f from b; ODc9r }
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) =.|J!x
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (3[z%@I
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. H$ftGwS8
4、说明:子查询(表名1:a 表名2:b) }7{t^>;D
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) }
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5、说明:显示文章、提交人和最后回复时间 % |q0-x
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b NVIK>cT6
6、说明:外连接查询(表名1:a 表名2:b) a"/#+=[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4RKW
7、说明:在线视图查询(表名1:a ) 5dx&Qu'}ZS
select * from (SELECT a,b,c FROM a) T where t.a > 1; vN4Qdpdb
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^t(^9
select * from table1 where time between time1 and time2 H9 C9P17
select a,b,c, from table1 where a not between 数值1 and 数值2 !$A 37j6
9、说明:in 的使用方法 iFSJL,QZ3
select * from table1 where a [not] in ('值1','值2','值4','值6') jNwjK0?
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3:"]Rn([P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 9p$V)qdX
11、说明:四表联查问题: @4%L36k
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 ..... GN#<yv$av
12、说明:日程安排提前五分钟提醒 xE}VTHFo'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 j4FeSGa
13、说明:一条sql 语句搞定数据库分页 , "jbq~
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 5`~mmAUk;`
14、说明:前10条记录 lcON+j
select top 10 * form table1 where 范围 :"6q,W
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.) WWwUwUi
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _u"nvgVz9
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 It_M@
(select a from tableA ) except (select a from tableB) except (select a from tableC) X u"R^
17、说明:随机取出10条数据 OE)~yKy
select top 10 * from tablename order by newid() /wQL
18、说明:随机选择记录 ]U[X1W+@
select newid() $=sXAK9
19、说明:删除重复记录 QU{Ech'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ggtDN{t
20、说明:列出数据库里所有的表名 C0.'_
select name from sysobjects where type='U' gw+9x<e
21、说明:列出表里的所有的 {qKxz9.y
select name from syscolumns where id=object_id('TableName') IM=bK U
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。 _2fkb=2@
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 &m3.h!dq
显示结果: |VOg\[f
type vender pcs 3`hUo5K
电脑 A 1 <VjJAu
电脑 A 1 BhpOXqg
光盘 B 2 wI M{pK
光盘 A 2 RO\gax
手机 B 3 aI
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手机 C 3 u{&B^s)k.
23、说明:初始化表table1 +c:3o*
TRUNCATE TABLE table1 ?[ly`>KpJ
24、说明:选择从10到15的记录 r#WT`pav
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4!$
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三、技巧 LW#M@
1、1=1,1=2的使用,在SQL语句组合时用的较多 x+? 9C
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LiDvaF:@L!
如: fkfZ>D^1
if @strWhere !='' #Z=tJ
begin #gQF'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere LCXO>MXN
end MB);!qy
else ;S$Ll*f>D
begin 9L%I<5i
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,O=a*%0rt
end f<i7@%
我们可以直接写成 >Sk[vI0Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere '2J0>Bla
2、收缩数据库 XA0(f*
--重建索引 "re-@Baw
DBCC REINDEX ^s7,_!.Pq
DBCC INDEXDEFRAG fLN! EDq
--收缩数据和日志 6XEZ4QP}
DBCC SHRINKDB WV;=@v
DBCC SHRINKFILE 4kp im
3、压缩数据库 k0?ZYeHC
dbcc shrinkdatabase(dbname) @mw "W{
4、转移数据库给新用户以已存在用户权限 m:tiY
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exec sp_change_users_login 'update_one','newname','oldname' 5FvOznK^e
go ${~|+zdB
5、检查备份集 NCeaL-y7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ~ <0Z>qr
6、修复数据库 oR+-+-??$
ALTER DATABASE [dvbbs] SET SINGLE_USER &Y|Xd4:
GO \v@({nB8
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK O/AE}]
GO 1N`vCt]w
ALTER DATABASE [dvbbs] SET MULTI_USER }6RT,O g
GO 3{raKM6F
7、日志清除 wWW~_zP0
SET NOCOUNT ON 2H#N{>7
DECLARE @LogicalFileName sysname,
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@MaxMinutes INT, =Cf]
@NewSize INT `&7RMa4=
USE tablename -- 要操作的数据库名 _68BP)nz>.
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 noVa=aU^
@MaxMinutes = 10, -- Limit on time allowed to wrap log. dLh6:Gh8_I
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2f, B$-#
-- Setup / initialize MKGS`X]<J
DECLARE @OriginalSize int TT!ET<ciN
SELECT @OriginalSize = size tgFJZA
FROM sysfiles HP2wtN{Zs
WHERE name = @LogicalFileName ^z1IN-Tm/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;Kxbg>U
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + >.9eBz@
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ry;$^.7%
FROM sysfiles Aw^yH+ae
WHERE name = @LogicalFileName 8 ,}ikOZ?
CREATE TABLE DummyTrans V*n==Nb5L
(DummyColumn char (8000) not null) >G)qns9
DECLARE @Counter INT,
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@StartTime DATETIME, >O{7/)gS^
@TruncLog VARCHAR(255) ^%bBW6eZ
SELECT @StartTime = GETDATE(), u4'z$>B
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ~2}Pl)
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <dR,'
EXEC (@TruncLog) </oY4$ l'
-- Wrap the log if necessary. =WZ%H_oxi
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired I@7/jUO
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <zB*'m
AND (@OriginalSize * 8 /1024) > @NewSize oN2=DYC41
BEGIN -- Outer loop. e=f .y<
SELECT @Counter = 0 q|#MB7e/
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _+QwREP
BEGIN -- update QEJGnl676
INSERT DummyTrans VALUES ('Fill Log') +H'\3^C-
DELETE DummyTrans <bmLy_":
SELECT @Counter = @Counter + 1 s3t!<9[m
END /lD?VE
EXEC (@TruncLog) )*1.eObhL
END M-9gD[m
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $3
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !e8i/!}^S
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' e1 a*'T$z
FROM sysfiles tm)*2lH6
WHERE name = @LogicalFileName L@)&vn]
DROP TABLE DummyTrans ?X_V#8JK
SET NOCOUNT OFF ym%slg
8、说明:更改某个表 jz:gr=*z
exec sp_changeobjectowner 'tablename','dbo' QXQ
9、存储更改全部表 r'aY2n^O
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch mN1Ssq"B
@OldOwner as NVARCHAR(128), SE `l(-tL
@NewOwner as NVARCHAR(128) 7 ^I:=qc72
AS c?6d2jH.
DECLARE @Name as NVARCHAR(128) ?b$3ob"
DECLARE @Owner as NVARCHAR(128) :EHQ .^
DECLARE @OwnerName as NVARCHAR(128) %xg"Q|
DECLARE curObject CURSOR FOR }=@zj6AC
select 'Name' = name, T%I&txl
'Owner' = user_name(uid) 4,}GyVJFb`
from sysobjects xPQL?.
where user_name(uid)=@OldOwner xb^Mo.\[
order by name 1bRL"{m^)-
OPEN curObject gg]~2f
FETCH NEXT FROM curObject INTO @Name, @Owner l]5%
WHILE(@@FETCH_STATUS=0) !Yh}H<w0
BEGIN lizTRVBE
if @Owner=@OldOwner m^tNqJs8
begin DX@}!6|T
set @OwnerName = @OldOwner + '.' + rtrim(@Name) rihlae5Kz
exec sp_changeobjectowner @OwnerName, @NewOwner 1D1b"o
end S<oQ}+4[~
-- select @name,@NewOwner,@OldOwner hZuYdV{'h
FETCH NEXT FROM curObject INTO @Name, @Owner %W;u}`
END g_ M-F
close curObject -9G]x{>
deallocate curObject Dd/}Ya(Gi
GO 1%eLs=u?
10、SQL SERVER中直接循环写入数据 a$+#V=bA
declare @i int q|{tQJfYg
set @i=1 Z{}+)Q*Q
while @i<30 |~NeB"l{
begin R<g =\XO'y
insert into test (userid) values(@i) *Mi6
set @i=@i+1 `pYE[y+
end FmA-OqEpA
小记存储过程中经常用到的本周,本月,本年函数 lIq~~cv)
Dateadd(wk,datediff(wk,0,getdate()),-1) k+\7B}7F
Dateadd(wk,datediff(wk,0,getdate()),6) v MWC(m
Dateadd(mm,datediff(mm,0,getdate()),0) bOXh|u_3i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) f[@#7,2~M
Dateadd(yy,datediff(yy,0,getdate()),0) d| \#?W&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) a;p6?kv
上面的SQL代码只是一个时间段 MZ^Ch
Dateadd(wk,datediff(wk,0,getdate()),-1) y h-9u
Dateadd(wk,datediff(wk,0,getdate()),6) 4TJ!jDkox
就是表示本周时间段. -A@U0=o
下面的SQL的条件部分,就是查询时间段在本周范围内的: s5.k|!K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) XI
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而在存储过程中 \>[gl!B_Rr
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >@Khm"/T
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) }85#[~m'