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。 tJy6\~
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一、基础 QXqBb$AXi,
1、说明:创建数据库 \74+ cN
CREATE DATABASE database-name zpx
2、说明:删除数据库 ^P
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drop database dbname hJ 4]GA'
3、说明:备份sql server 6":=p:PT.
--- 创建 备份数据的 device Z.Z+cFi
USE master R_eKKi@VH
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' l 3bo
--- 开始 备份 6;i]v|M-
BACKUP DATABASE pubs TO testBack 4<CHwIRHY
4、说明:创建新表 %|bqL3)a_
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) q$7WZ+Y\
根据已有的表创建新表: ^\Gaf5{
A:create table tab_new like tab_old (使用旧表创建新表) 48nZ
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B:create table tab_new as select col1,col2... from tab_old definition only jXB<"bw
5、说明:删除新表 H@GiHej
drop table tabname Ufd{.o[{-
6、说明:增加一个列 `6koQZm
Alter table tabname add column col type D6@c&
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 P#]%C
7、说明:添加主键: Alter table tabname add primary key(col) %b<cJ]F
说明:删除主键: Alter table tabname drop primary key(col) ?NoG.
8、说明:创建索引:create [unique] index idxname on tabname(col....) G]X72R?g
删除索引:drop index idxname E+k#1c|v$
注:索引是不可更改的,想更改必须删除重新建。 i9+(gX(t
9、说明:创建视图:create view viewname as select statement eSHyA+F
删除视图:drop view viewname _"%mLH=!8
10、说明:几个简单的基本的sql语句 3QM6M9M
选择:select * from table1 where 范围 4Z5ZV!
插入:insert into table1(field1,field2) values(value1,value2) DS0c0lsx
删除:delete from table1 where 范围 JJ[.K*dO
更新:update table1 set field1=value1 where 范围 Z;`ts/?SY]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! eD5.*O
排序:select * from table1 order by field1,field2 [desc] {0
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总数:select count as totalcount from table1 &[ejxK"
求和:select sum(field1) as sumvalue from table1 2'UWPZgE
平均:select avg(field1) as avgvalue from table1 Rqu_[M
最大:select max(field1) as maxvalue from table1 g0NtM%
最小:select min(field1) as minvalue from table1 s ki'I
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11、说明:几个高级查询运算词 'M+iw:R__
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A: UNION 运算符 U[1Rw6
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。 Ze_4MwCW
B: EXCEPT 运算符 N#
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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。 S) ZcH
C: INTERSECT 运算符 h3U| ~h
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。 H=O/w3
注:使用运算词的几个查询结果行必须是一致的。 CmKbpN*
12、说明:使用外连接 |X@ZM
A、left outer join: LPO:Ka
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。 ZqH.$nXP
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c f*U3s N^y
B:right outer join: %>u(UmFO
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 KPc`5X
C:full outer join: U7i WYdt$
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。 Hz39v44
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二、提升 If[4]-dq
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~~,] b
法一:select * into b from a where 1<>1 (Ubz@s^
法二:select top 0 * into b from a ^ z!g3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) D>neY9
insert into b(a, b, c) select d,e,f from b; c&4EO|
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) C],"va
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 .)J7 \z8m
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ;Qe-y|>
4、说明:子查询(表名1:a 表名2:b) ;>YLL}]j
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) @$o.Z;83`r
5、说明:显示文章、提交人和最后回复时间 &/o4R:i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b otTv,T182
6、说明:外连接查询(表名1:a 表名2:b) W>$2BsO
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c jNRR=0
7、说明:在线视图查询(表名1:a ) RN2^=$'.
select * from (SELECT a,b,c FROM a) T where t.a > 1; HoE@t-S
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 5eS0
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select * from table1 where time between time1 and time2 U4`6S43ki
select a,b,c, from table1 where a not between 数值1 and 数值2 ;nS.t_UW.
9、说明:in 的使用方法 lsJl+%&8
select * from table1 where a [not] in ('值1','值2','值4','值6') V?pqKQL0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 YQ/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) K[{hh;7
11、说明:四表联查问题: dQW=k^X 'U
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 ..... C]/]ot0%t
12、说明:日程安排提前五分钟提醒 G':wJ7[]`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lRb|GS.h/
13、说明:一条sql 语句搞定数据库分页 y~eQVnH5W
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 &!Sq6<!v2
14、说明:前10条记录 W&MZ5t,k=
select top 10 * form table1 where 范围 J)7m::%I
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.) rLP:kP'b
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) DAYR=s
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 Ss>ez8q
(select a from tableA ) except (select a from tableB) except (select a from tableC) -lICoRO#
17、说明:随机取出10条数据 vlW521
select top 10 * from tablename order by newid() rf@Cz%xDD
18、说明:随机选择记录 )T2V<3l
select newid() d'p]F~a
19、说明:删除重复记录 \.!+'2!m
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) e'"2yA8dh"
20、说明:列出数据库里所有的表名 N>a. dYXr
select name from sysobjects where type='U' ,_+Gb
21、说明:列出表里的所有的 gl.uDO%.
select name from syscolumns where id=object_id('TableName') (^),G-]
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。 S(*u_
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 YF)uAJ Ak
显示结果: barY13)$U
type vender pcs $qndG,([F
电脑 A 1 Vc2(R^
电脑 A 1 K14FY2"
光盘 B 2 u?Pec:3%
光盘 A 2 3:H[S_q
手机 B 3 S=f:-?N|
手机 C 3 r1pj-
23、说明:初始化表table1 {Sl#z}@s
TRUNCATE TABLE table1 w^BF.Nu
24、说明:选择从10到15的记录 ML:Zm~A1U
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Ufw_GYxan
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三、技巧 E}qW'
1、1=1,1=2的使用,在SQL语句组合时用的较多 p"'knZG
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U!y GZEU"[
如: m/E$0tf
if @strWhere !='' /-FvC^Fj
begin e^ Aw%t
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere FqWW[Bgd
end d+m}Z>iQ1O
else }Mv$Up
begin P]A~:Lj
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?:$aX@r
end 5I`_SOa!
我们可以直接写成 Yo-$Z-ud
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere T<a/GE/
2、收缩数据库 fpPB_P{Ua
--重建索引 U))2?#
DBCC REINDEX #B$r|rqamq
DBCC INDEXDEFRAG J=l\t7w
--收缩数据和日志 :abpht
DBCC SHRINKDB >Tf <8r,
DBCC SHRINKFILE TWU[/>K
3、压缩数据库 +hZ{/
dbcc shrinkdatabase(dbname) ByU&fx2Z
4、转移数据库给新用户以已存在用户权限 XJSI/jpa@
exec sp_change_users_login 'update_one','newname','oldname' &mPR[{
go H6.
5、检查备份集 L\cbY6b
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' XI5TVxo(q
6、修复数据库 \Bvy~UeE)>
ALTER DATABASE [dvbbs] SET SINGLE_USER $wm.,Vb
GO ##QKXSD
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >2^|r8l5
GO <V
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ALTER DATABASE [dvbbs] SET MULTI_USER oR@emYL
GO l_lK,=cLj+
7、日志清除 &_1x-@oI2:
SET NOCOUNT ON j9sLR
DECLARE @LogicalFileName sysname, y 1I(^<qO=
@MaxMinutes INT, 8
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@NewSize INT eaWK2%v
USE tablename -- 要操作的数据库名 Z@ dS,M*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 'pa8h L
@MaxMinutes = 10, -- Limit on time allowed to wrap log. B]nu \!
@NewSize = 1 -- 你想设定的日志文件的大小(M) ^[=1J
-- Setup / initialize >gTQD\k:D
DECLARE @OriginalSize int j>I.d+
SELECT @OriginalSize = size s$3WJ'yr
FROM sysfiles yhsbso,5 a
WHERE name = @LogicalFileName j
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + o4qB0h
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + .-mlV ^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 9Od|R"aS|
FROM sysfiles ^ZD0rp(l
WHERE name = @LogicalFileName 3?x}48
CREATE TABLE DummyTrans 9O{b8=\}
(DummyColumn char (8000) not null) V9\y*6#Y,
DECLARE @Counter INT, dfR?O#JPU
@StartTime DATETIME, ?y|8bw<
@TruncLog VARCHAR(255) gyT3[*eh
SELECT @StartTime = GETDATE(), lHc|:vG?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1i=p5,|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4yDWVd;
EXEC (@TruncLog) KB`">zq$u
-- Wrap the log if necessary. 8(@Y@`/
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired '-2|GX_o
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) j"4]iI+ {"
AND (@OriginalSize * 8 /1024) > @NewSize hmES@^n!_
BEGIN -- Outer loop. Yw6d-5=:
SELECT @Counter = 0 W5U;{5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Egm-PoPe
BEGIN -- update X B[C&3I
INSERT DummyTrans VALUES ('Fill Log') Fu*Qci1Z
DELETE DummyTrans E/Adi^
SELECT @Counter = @Counter + 1 /zTx+U.\I
END oFDJwOJ'Bj
EXEC (@TruncLog) /8[T2Z!
END xN>+!&3%w
SELECT 'Final Size of ' + db_name() + ' LOG is ' + FNHJHuTe
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _OY<Hb3%M
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' {^N90,!
FROM sysfiles T,uVt^.R+
WHERE name = @LogicalFileName &m~
DROP TABLE DummyTrans d$<1Ma}
SET NOCOUNT OFF w<me(!-'
8、说明:更改某个表 Y{c+/n3d
exec sp_changeobjectowner 'tablename','dbo' <;q)V%IUz
9、存储更改全部表 gMB/ ~g5b0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 2O+fjs
@OldOwner as NVARCHAR(128), Y}hz UKJ
@NewOwner as NVARCHAR(128) m'"Ra-
AS FZ@8&T
DECLARE @Name as NVARCHAR(128) |W;EPQ+<
DECLARE @Owner as NVARCHAR(128) LT:*K!>NOL
DECLARE @OwnerName as NVARCHAR(128) rCn"{.rI
DECLARE curObject CURSOR FOR 'qlWDt/
select 'Name' = name, M^?=!!US^
'Owner' = user_name(uid) 8
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from sysobjects v>'mW
where user_name(uid)=@OldOwner Y^ti;:
order by name -FW'i10\2+
OPEN curObject .{Df"e>
FETCH NEXT FROM curObject INTO @Name, @Owner >vk?wY^f
WHILE(@@FETCH_STATUS=0) :qxd
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BEGIN 0qk.NPMB0
if @Owner=@OldOwner .9u,54t
begin fud Lm
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fS- 31<?
exec sp_changeobjectowner @OwnerName, @NewOwner h@D</2>
end nk+*M9r|I
-- select @name,@NewOwner,@OldOwner xyaU!E*
FETCH NEXT FROM curObject INTO @Name, @Owner b 1t7/q
END Z<~^(W7h
close curObject DOGg=`XK1
deallocate curObject ]qNPOnlp
GO 8+U':xR
10、SQL SERVER中直接循环写入数据 90]{4 ]y;
declare @i int ealh>Y
set @i=1 [0-zJy|,
while @i<30 Jm{~H%
begin <#5`%sa '
insert into test (userid) values(@i) hP]zC1s
set @i=@i+1 &xjeZh4-
end &Vi0.o
小记存储过程中经常用到的本周,本月,本年函数 !e(ZEV g
Dateadd(wk,datediff(wk,0,getdate()),-1) #Cz6c%yK
Dateadd(wk,datediff(wk,0,getdate()),6) ey3;rY1
Dateadd(mm,datediff(mm,0,getdate()),0) hXM2B2[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) MESPfS+
Dateadd(yy,datediff(yy,0,getdate()),0) %Q[+bN[/
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) m[!AOln)
上面的SQL代码只是一个时间段 >6cENe_@t
Dateadd(wk,datediff(wk,0,getdate()),-1) :fE*fU@
Dateadd(wk,datediff(wk,0,getdate()),6) `<kV)d%xEF
就是表示本周时间段. "K*+8IO2
下面的SQL的条件部分,就是查询时间段在本周范围内的: WX9pJ9d
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +gsk}>"
而在存储过程中 DU:
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S&m5]h!D
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Le':b2o