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。 HbfB[%
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一、基础 lkg*AAR?'
1、说明:创建数据库 Z[S+L"0
CREATE DATABASE database-name hyfnIb@~}
2、说明:删除数据库 PZRn6Tc
drop database dbname .{a2z*o
3、说明:备份sql server bK8F |
--- 创建 备份数据的 device r Ob"S*
USE master :yjK*"T|OD
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ZCFf@2&z8
--- 开始 备份 eSNSnh]'
BACKUP DATABASE pubs TO testBack xcvr D
4、说明:创建新表 '#PqI)P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) wKS-O%?
根据已有的表创建新表: gam#6
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A:create table tab_new like tab_old (使用旧表创建新表) )NmlV99q
B:create table tab_new as select col1,col2... from tab_old definition only /
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5、说明:删除新表 vSC0D7BlG
drop table tabname OrEuQ-,i@
6、说明:增加一个列 k5;Vl0Ho
Alter table tabname add column col type KI@
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。 xf"5<PTW</
7、说明:添加主键: Alter table tabname add primary key(col) E+ 3yN\X(
说明:删除主键: Alter table tabname drop primary key(col) Df:7P>
8、说明:创建索引:create [unique] index idxname on tabname(col....) A
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删除索引:drop index idxname uoY`qF.`
注:索引是不可更改的,想更改必须删除重新建。 _pko]F|()
9、说明:创建视图:create view viewname as select statement {hRie+
删除视图:drop view viewname !M&un*
10、说明:几个简单的基本的sql语句 Wo9psv7.
选择:select * from table1 where 范围 Tb1}XvZ
插入:insert into table1(field1,field2) values(value1,value2) 9_WPWFO
删除:delete from table1 where 范围 fb.\V]K
更新:update table1 set field1=value1 where 范围 F:o#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! I,4-
排序:select * from table1 order by field1,field2 [desc] ,o@~OTja*
总数:select count as totalcount from table1 27E9NO=
求和:select sum(field1) as sumvalue from table1 ,' rL'Ys
平均:select avg(field1) as avgvalue from table1 \y H3Y
最大:select max(field1) as maxvalue from table1 /E{dM2
最小:select min(field1) as minvalue from table1 4[,B ;7
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11、说明:几个高级查询运算词 f./m7TZ
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A: UNION 运算符 c\)&yGE
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。 cP@F
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B: EXCEPT 运算符 f UF;SqT
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 ctSS:1
C: INTERSECT 运算符 s|gD
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。 u2-@?yt
注:使用运算词的几个查询结果行必须是一致的。 nz(q)"A
12、说明:使用外连接 me:|!lI7YU
A、left outer join: &xBK\
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。 BnaU)E h
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 ,>
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B:right outer join: }x?H ~QQT
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。 1KYbL8c
C:full outer join: 8S1P&+iKs
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。 RHx+HBZ
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二、提升 nRXSW&V"m
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) kUg+I_j6*
法一:select * into b from a where 1<>1 UGmuX:@y76
法二:select top 0 * into b from a :qAc= IC%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) k)5_1 y
insert into b(a, b, c) select d,e,f from b; _iGU|$a
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) iL0jpa<}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 wAu[pWD'6;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. xv$)u<Ve
4、说明:子查询(表名1:a 表名2:b) JXL9Gge
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) @Xve qUUU
5、说明:显示文章、提交人和最后回复时间 S0N2rU
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b t8AkdSU0
6、说明:外连接查询(表名1:a 表名2:b) b@wBR9s
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C,{F0-D
7、说明:在线视图查询(表名1:a ) XatA8(_,5
select * from (SELECT a,b,c FROM a) T where t.a > 1; Cgz&@@j,]
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 Z\|u9DO
select * from table1 where time between time1 and time2 h
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select a,b,c, from table1 where a not between 数值1 and 数值2 WjY{rM,K
9、说明:in 的使用方法 vr{'FMc
select * from table1 where a [not] in ('值1','值2','值4','值6') 5>ADw3z'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0Oc}rRH(C
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) >lraYMc<rZ
11、说明:四表联查问题: `y^zM/Ib
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 ..... *U;4t/(
12、说明:日程安排提前五分钟提醒 X`fhln9N
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 5@ bc(H
13、说明:一条sql 语句搞定数据库分页 c{mKra
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 >P\h,1
14、说明:前10条记录 A,m4WO_q3
select top 10 * form table1 where 范围 DHm[8 Qp
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.) ~JwpNJs
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ShWHHU(QQ
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 G{NSAaD[
(select a from tableA ) except (select a from tableB) except (select a from tableC) CJ9cCtA
17、说明:随机取出10条数据 %XJQ0CE<(
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 G Sz @rDGY
select newid() DO&+=o`"
19、说明:删除重复记录 cW)Oi^q%o2
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) NZo<IKD$
20、说明:列出数据库里所有的表名 oe(9mYWKa6
select name from sysobjects where type='U' t1e4H=d>
21、说明:列出表里的所有的 01LZE,.
select name from syscolumns where id=object_id('TableName') %bIsrQ~B
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。 xdd:yrC
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 ~~C6)N~1
显示结果: ~@T+mHny
type vender pcs X0y?<G1(a
电脑 A 1 i>Z|6 5
电脑 A 1 L w>-7)
光盘 B 2 F8{ldzh
光盘 A 2 M`0(!Q}
手机 B 3 0LWdJ($?
手机 C 3 F+ffl^BQ
23、说明:初始化表table1 ";PG%_(
TRUNCATE TABLE table1 AH&9Nye8
24、说明:选择从10到15的记录 Md8(`@`o
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |Du,UY/
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三、技巧 9t{|_G
1、1=1,1=2的使用,在SQL语句组合时用的较多 }FPM-M3y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, {UB%(E[Mr
如: HUj+-
if @strWhere !='' [O^}rUqq
begin N0=-7wMk(Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CE~r4
end f%2%T'Q
else hzaLx8L
begin [J~aAB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
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end 6#<Ir @z
我们可以直接写成 n}19?K]g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [ZuVUOm
2、收缩数据库 B ,V(LTE
--重建索引 kr^0% A
DBCC REINDEX 5B%w]n
DBCC INDEXDEFRAG F(deu^s%{
--收缩数据和日志 ucw`;<d8
DBCC SHRINKDB 49o\^<4b
DBCC SHRINKFILE Iq+2mQi*/k
3、压缩数据库 I$n+DwKcN
dbcc shrinkdatabase(dbname) iwUv`>l&
4、转移数据库给新用户以已存在用户权限 eaEbH2J
exec sp_change_users_login 'update_one','newname','oldname' SGt5~Txj
go O{~KR/
5、检查备份集 >wA+[81[
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' + a-D#^2;
6、修复数据库 _0K.Fk*(!
ALTER DATABASE [dvbbs] SET SINGLE_USER RF:04d
GO Ddb-@YD&+0
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK i&JpM]N
GO *m*`}9
ALTER DATABASE [dvbbs] SET MULTI_USER +@e
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GO >E,Q
7、日志清除 EOhC6>ATh
SET NOCOUNT ON }"hW b(
DECLARE @LogicalFileName sysname, 6.[)`iF+#
@MaxMinutes INT, ^;+[8:Kb
@NewSize INT gSb,s [p&+
USE tablename -- 要操作的数据库名 0Q7MM6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $%=G[/i'
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Y~}5axSPH
@NewSize = 1 -- 你想设定的日志文件的大小(M) i0\)%H:z
-- Setup / initialize J smB^
DECLARE @OriginalSize int H;QA@tF>5
SELECT @OriginalSize = size s"WBw'_<<
FROM sysfiles z|I0-1tAK
WHERE name = @LogicalFileName L/yaVU{aEb
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p-xd k|'[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )&:L'N
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +pz}4M`
FROM sysfiles t!jYu<P
WHERE name = @LogicalFileName ?_%u)S*g
CREATE TABLE DummyTrans W&YU^&`Yr
(DummyColumn char (8000) not null) w.z<60%},0
DECLARE @Counter INT, ^^U%cu Kg
@StartTime DATETIME, T cJ$[
@TruncLog VARCHAR(255) wx*1*KZ
SELECT @StartTime = GETDATE(), >'b=YlUL
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' )S*1C@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <: :VCA %
EXEC (@TruncLog) s1bU
-- Wrap the log if necessary. hO3{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Wo!;K|~P
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) u h)o
AND (@OriginalSize * 8 /1024) > @NewSize CW p#^1F
BEGIN -- Outer loop. 1'Rmg\(
SELECT @Counter = 0 W:vr@e6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) FY4 T(4#
BEGIN -- update y^R4I_* z
INSERT DummyTrans VALUES ('Fill Log') ezUQ>
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DELETE DummyTrans RYy,wVh}
SELECT @Counter = @Counter + 1 pawl|Z'Ez
END aClA{
EXEC (@TruncLog) g*J@[y;
END ~x#vZ=]8
SELECT 'Final Size of ' + db_name() + ' LOG is ' + N}x9N.
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Xb,T{.3@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles ;&S;%W>|
WHERE name = @LogicalFileName 9->q| E4
DROP TABLE DummyTrans y`So&:1
SET NOCOUNT OFF m*Cu-6&qd
8、说明:更改某个表 o2naVxetE
exec sp_changeobjectowner 'tablename','dbo' Skxd<gv
9、存储更改全部表 $(rc/h0/E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 2+Yb
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@OldOwner as NVARCHAR(128), e <"/'Ql!k
@NewOwner as NVARCHAR(128)
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AS 2w?hgNz
DECLARE @Name as NVARCHAR(128) vy9dAl
DECLARE @Owner as NVARCHAR(128) Q4Q pn
DECLARE @OwnerName as NVARCHAR(128) Ur3m[07H
DECLARE curObject CURSOR FOR WbcS: !0
select 'Name' = name, 4TZ cc|B5
'Owner' = user_name(uid) J#
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from sysobjects :c=.D;,
where user_name(uid)=@OldOwner cbYK5fj"T
order by name (s&&>M]r_
OPEN curObject ?JXa~.dA
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) g)1X&>
BEGIN dYF=c
if @Owner=@OldOwner 1m)M;^_
begin [>Fm[5x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) W5 ec
exec sp_changeobjectowner @OwnerName, @NewOwner #|f~s
end JN(-.8<
-- select @name,@NewOwner,@OldOwner uMd. j$$
FETCH NEXT FROM curObject INTO @Name, @Owner BJy;-(JP
END +>tUz D
close curObject Fr [7
deallocate curObject ;gB`YNL
GO yWb4Ify
10、SQL SERVER中直接循环写入数据 ej^3YNh&
declare @i int GLUUY0
set @i=1 Ow/@Z7~
while @i<30 <]U1\~j
begin izwUS!5e
insert into test (userid) values(@i) v~=\H
set @i=@i+1 #ekM"p
end DNP@A4~
小记存储过程中经常用到的本周,本月,本年函数 iqPBsIW
Dateadd(wk,datediff(wk,0,getdate()),-1) '*T]fND4
Dateadd(wk,datediff(wk,0,getdate()),6) LW:1/w&pv
Dateadd(mm,datediff(mm,0,getdate()),0) #/70!+J_UF
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) (kw5>c7
Dateadd(yy,datediff(yy,0,getdate()),0) e.vtEQV9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) {vVTv SC
上面的SQL代码只是一个时间段 :]II-$/8
Dateadd(wk,datediff(wk,0,getdate()),-1) Ed-M7#wY
Dateadd(wk,datediff(wk,0,getdate()),6) tSHFm-q`
就是表示本周时间段. 0xMj=3']
下面的SQL的条件部分,就是查询时间段在本周范围内的: 3)N\'xFh@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) i$uN4tVKT
而在存储过程中 .%}+R|g
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]Kh2;>=
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8Vn4.R[vE