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。 rR7}SEa
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一、基础 A5z`3T;1
1、说明:创建数据库 Tx!mW-Lt
CREATE DATABASE database-name K
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2、说明:删除数据库 WB= gN:?
drop database dbname S]<Hx_[}
3、说明:备份sql server NZ
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--- 创建 备份数据的 device E;+3VJ+F"
USE master U*6r".sz
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [1s B
--- 开始 备份 rc"Z$qU?
BACKUP DATABASE pubs TO testBack U#Ud~Q q
4、说明:创建新表 U?kJXM2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kefQH\<X
根据已有的表创建新表: ?&N
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A:create table tab_new like tab_old (使用旧表创建新表) . [C~a
B:create table tab_new as select col1,col2... from tab_old definition only xL mo?Y*
5、说明:删除新表 fFsA[@5tul
drop table tabname lc*<UZR
6、说明:增加一个列 aK,G6y
Alter table tabname add column col type ATwPfo8jx@
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 KF-n_:Bd+
7、说明:添加主键: Alter table tabname add primary key(col) E")82I
说明:删除主键: Alter table tabname drop primary key(col) |n~-LH++
8、说明:创建索引:create [unique] index idxname on tabname(col....) pN?
删除索引:drop index idxname 7^ER?@:W
注:索引是不可更改的,想更改必须删除重新建。 or0f%wAF
9、说明:创建视图:create view viewname as select statement @k6>&PS
删除视图:drop view viewname &u.t5m7(
10、说明:几个简单的基本的sql语句 ]A'E61t<n
选择:select * from table1 where 范围 O7E0{8
插入:insert into table1(field1,field2) values(value1,value2) {
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删除:delete from table1 where 范围 H1N%uk=kV
更新:update table1 set field1=value1 where 范围 Iz
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! c$>Tfa'H
排序:select * from table1 order by field1,field2 [desc] G6L'RP
总数:select count as totalcount from table1 aj1Zi3h
求和:select sum(field1) as sumvalue from table1 TJ+yBMd*%
平均:select avg(field1) as avgvalue from table1 ,%Dn}mWu
最大:select max(field1) as maxvalue from table1 +Ge-!&.;A
最小:select min(field1) as minvalue from table1 )y._]is)b
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11、说明:几个高级查询运算词 58WL8xu
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A: UNION 运算符 @<;0h|
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。 G/=tC8eX
B: EXCEPT 运算符 ]x?`&f8i
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。 RH~KaV3
C: INTERSECT 运算符 06L/i,
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。 S)p1[&" M
注:使用运算词的几个查询结果行必须是一致的。 3s"x{mtH
12、说明:使用外连接 81`-xVd
A、left outer join: ;j S~0R
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。 I)T]}et
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 -FdhV%5]
B:right outer join: aO6w:IO
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。 Q/L:0ovR
C:full outer join: :IvKxOv
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。 d/N&bTg:
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二、提升 "/g/Lc
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) fn]f$n*`
法一:select * into b from a where 1<>1 ^GHA,cSf
法二:select top 0 * into b from a F^z&s]^~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 9F@ Q
insert into b(a, b, c) select d,e,f from b; CB\E@u,
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) n](Q)h'nlo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Jwgd9a5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .gzNdSE
4、说明:子查询(表名1:a 表名2:b) ZxLgV$U
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) .3M=|rE
5、说明:显示文章、提交人和最后回复时间 ]gx]7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b CM|?;PBuv
6、说明:外连接查询(表名1:a 表名2:b) |aIY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,p {|f}0
7、说明:在线视图查询(表名1:a ) 9/'zk
select * from (SELECT a,b,c FROM a) T where t.a > 1; F=bX\T7
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 V]&0"HX2r!
select * from table1 where time between time1 and time2 <XDYnWz
select a,b,c, from table1 where a not between 数值1 and 数值2 &3#19v7/
9、说明:in 的使用方法 ef *Vs
select * from table1 where a [not] in ('值1','值2','值4','值6') vu Vcv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 H}Z\r2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 2guWWFS
11、说明:四表联查问题: 2M1}`H\
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 ..... L/t'|<m
12、说明:日程安排提前五分钟提醒 iK%%
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lpi^<LQ@l
13、说明:一条sql 语句搞定数据库分页 __O@w.
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 w7+3?'L
14、说明:前10条记录 OXAr..
select top 10 * form table1 where 范围 $qO%lJ:
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 8A}cxk
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) L"e8S%UqX
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 Po_y78ZD
(select a from tableA ) except (select a from tableB) except (select a from tableC) `o4alK\
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() G
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18、说明:随机选择记录 js^+ {~
select newid() DPqk~ KCM
19、说明:删除重复记录 bh
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #2{H!jr
20、说明:列出数据库里所有的表名 i-Er|u; W
select name from sysobjects where type='U' tX)l_?jVH
21、说明:列出表里的所有的 1<766
select name from syscolumns where id=object_id('TableName') uI lm!*0
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 F8Y_L\q
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type +J[<zxh\
显示结果: _[IOPHa"
type vender pcs M5\$+Tu
电脑 A 1 'ONCz
电脑 A 1 _ x8gEK8
光盘 B 2 t`%Xxxu
光盘 A 2 3}hJ`xQ
手机 B 3 oA+/F]XJ
手机 C 3 !79eF)
23、说明:初始化表table1 -9)H[}.
TRUNCATE TABLE table1 ;D'6sd"
24、说明:选择从10到15的记录 >x'R7z23
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc N5K\h}'%
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三、技巧 !:BmDX[<n
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?5VPV9EX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ?/3'j(Gk
如: b}<?& @
if @strWhere !='' VkW N1A
begin |tn.ZEgw3~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ykMdH:
end n[+$a)$8
else w{+G/Ea
begin }aSTo"~m#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 05SK$
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end h[*:\P`
我们可以直接写成 F .hA.E
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %7}ibz4iF
2、收缩数据库 .s-V:k5
--重建索引 C"7-lz
DBCC REINDEX ~S\y)l\wZ
DBCC INDEXDEFRAG y).dw(
--收缩数据和日志 2UbTKN
DBCC SHRINKDB M1HGXdN* B
DBCC SHRINKFILE "Sb<"$:
3、压缩数据库 X^o0t^
dbcc shrinkdatabase(dbname) 1Y+g^Z;G
4、转移数据库给新用户以已存在用户权限 U,Q
exec sp_change_users_login 'update_one','newname','oldname' A r,fmq
go o{[w6^D7
5、检查备份集 b%wm-p
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +Z7:(o<
6、修复数据库 BS*Y3 $
ALTER DATABASE [dvbbs] SET SINGLE_USER 15J t
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GO vCX
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 0]k-0#JM
GO X:2)C-l?
ALTER DATABASE [dvbbs] SET MULTI_USER &9OnN<mT1
GO !FA[
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7、日志清除 -4Hf5!
SET NOCOUNT ON 2QIx~Er
DECLARE @LogicalFileName sysname, Ci9]#)"c
@MaxMinutes INT, K3dg.>O
@NewSize INT WzhY4"p
USE tablename -- 要操作的数据库名 rK~Obv
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 IeN~E'~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [6cF#_)*
@NewSize = 1 -- 你想设定的日志文件的大小(M) lY$9-Q(
-- Setup / initialize ;s\ck:Xg
DECLARE @OriginalSize int 328gTP1
SELECT @OriginalSize = size CpLLsp hy
FROM sysfiles qw<~v?{|C
WHERE name = @LogicalFileName iy-~CPNB_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F a+#bX7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + FKWL{"y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' wN]]t~K)Q
FROM sysfiles '5etZ!:
WHERE name = @LogicalFileName 1fMl8[!JLu
CREATE TABLE DummyTrans XMlcY;W
(DummyColumn char (8000) not null) It#T\fU
DECLARE @Counter INT, 3]rd!Gp=*
@StartTime DATETIME, ;%^T*?t
@TruncLog VARCHAR(255) Jp 7m$D%
SELECT @StartTime = GETDATE(), $+WMKv@<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Qv
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) Lq#$q>!K
EXEC (@TruncLog) )(V!& w6
-- Wrap the log if necessary. \AY*x=PF
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #-7w|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 6 K-jje;)
AND (@OriginalSize * 8 /1024) > @NewSize 8~|tl,
BEGIN -- Outer loop. >NJ`*M
SELECT @Counter = 0 $s<bKju
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) AGMrBd|J{
BEGIN -- update .azA1@V|
INSERT DummyTrans VALUES ('Fill Log') M0K+Vz=
DELETE DummyTrans _>u0vGF-
SELECT @Counter = @Counter + 1 _FxQl]@
END 5:vy_e&
EXEC (@TruncLog) yL#2|t(
END kWZ/O
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v=J[p;H^H
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + eh /QFm
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' >5M Hn@
FROM sysfiles Oi4y~C_Xd
WHERE name = @LogicalFileName krecUpo
DROP TABLE DummyTrans i p;
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SET NOCOUNT OFF ^3lEfI<pBm
8、说明:更改某个表 !Ct'H1J-
exec sp_changeobjectowner 'tablename','dbo' 94'0X
9、存储更改全部表 ^GC 8^f
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch s)5W:`MH?
@OldOwner as NVARCHAR(128), v]@n'!
@NewOwner as NVARCHAR(128) k:DAko}
AS C^fUhLVSZ^
DECLARE @Name as NVARCHAR(128) ;%mYsQ
DECLARE @Owner as NVARCHAR(128) u&Cu"-%=M
DECLARE @OwnerName as NVARCHAR(128) L4!T
DECLARE curObject CURSOR FOR \9%RY]TK3
select 'Name' = name, ICm/9Onh&
'Owner' = user_name(uid) `KHP?lX
from sysobjects JXAH/N&i
where user_name(uid)=@OldOwner EF8'ycJk+
order by name f0ME$:2
OPEN curObject VQ/Jz5^
FETCH NEXT FROM curObject INTO @Name, @Owner LWIPq"
WHILE(@@FETCH_STATUS=0) `kM:5f+>W
BEGIN j6#RV@ p`
if @Owner=@OldOwner [`U9
begin dW9Ci"~v
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Zd<8c^@
exec sp_changeobjectowner @OwnerName, @NewOwner (4"Azo*~![
end dFzlcKFFD
-- select @name,@NewOwner,@OldOwner M&ec%<lM
FETCH NEXT FROM curObject INTO @Name, @Owner A[Pz&\@
END w<jlE8u
close curObject @Rs3i;"W
deallocate curObject ]vUTb9>{?
GO cwBf((~
10、SQL SERVER中直接循环写入数据 M2rgB%W)m
declare @i int eGk`Z>
set @i=1 Y~g*"J5j
while @i<30 >Ni<itze$i
begin g/BlTi
insert into test (userid) values(@i) "2>_eZ#b
set @i=@i+1 C,G$C7$%
end <,huajQs
小记存储过程中经常用到的本周,本月,本年函数 zOT(>1'
Dateadd(wk,datediff(wk,0,getdate()),-1) u
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Dateadd(wk,datediff(wk,0,getdate()),6) 3-U@==:T
Dateadd(mm,datediff(mm,0,getdate()),0) sHf.xc
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) `%Jq^uW
Dateadd(yy,datediff(yy,0,getdate()),0) X.FFBKjf[e
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) uBA84r%{QQ
上面的SQL代码只是一个时间段 f+>g_Q
Dateadd(wk,datediff(wk,0,getdate()),-1) lAAs/
Dateadd(wk,datediff(wk,0,getdate()),6) 3!2TE -
就是表示本周时间段. &pEr;:E
下面的SQL的条件部分,就是查询时间段在本周范围内的: HiPd|D
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) b&xlT+GN
而在存储过程中 D&nVkZP>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) D/TEx2.=J3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) G;yh$n<"