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。 m&Lc."
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一、基础 s\i.pd:Q
1、说明:创建数据库 Ue0Q| h
CREATE DATABASE database-name 7<c&)No;
2、说明:删除数据库 S~4HFNe^&
drop database dbname i*%2 e)
3、说明:备份sql server }V
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--- 创建 备份数据的 device \^%5!
USE master Y/w) VV
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9 ulr6
--- 开始 备份 fO{E65uA
BACKUP DATABASE pubs TO testBack B^G{k3]t
4、说明:创建新表 @X6|[r&Z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) >SZ9,K4Gs
根据已有的表创建新表: ^,KN@
A:create table tab_new like tab_old (使用旧表创建新表) Q.[^5
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B:create table tab_new as select col1,col2... from tab_old definition only #%g~fh
5、说明:删除新表 iXDQ2&gE*
drop table tabname CQNt
6、说明:增加一个列 @7*Ag~MRb
Alter table tabname add column col type er0ClvB
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。 n"{oj7E0a
7、说明:添加主键: Alter table tabname add primary key(col) :}18G}B
说明:删除主键: Alter table tabname drop primary key(col) GQ8r5V4:
8、说明:创建索引:create [unique] index idxname on tabname(col....) [{B1~D-
删除索引:drop index idxname q3E_.{t
注:索引是不可更改的,想更改必须删除重新建。 '((Ll
9、说明:创建视图:create view viewname as select statement g1`/xJz|
删除视图:drop view viewname @Q atgYu
10、说明:几个简单的基本的sql语句 #/9(^6f:
选择:select * from table1 where 范围 R4|<Vp<U2
插入:insert into table1(field1,field2) values(value1,value2) Cz_chK4
删除:delete from table1 where 范围 d/ OIc){tD
更新:update table1 set field1=value1 where 范围 p
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! fE/8;v!=
排序:select * from table1 order by field1,field2 [desc] -j_J1P0,
总数:select count as totalcount from table1 8}W06k>)%
求和:select sum(field1) as sumvalue from table1 :1wMGk
平均:select avg(field1) as avgvalue from table1 ?y{C"w!
最大:select max(field1) as maxvalue from table1 %.R_[.W
最小:select min(field1) as minvalue from table1 ngN_,x7yc
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11、说明:几个高级查询运算词 _k@{>
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A: UNION 运算符 %?EOD=e=
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。 *<! W k\
B: EXCEPT 运算符 =`X@+~%-
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。 G
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C: INTERSECT 运算符 f. =4p^
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。 ZCMB]bL-e
注:使用运算词的几个查询结果行必须是一致的。 w%k)J{\
12、说明:使用外连接 ^q,KRut
A、left outer join: f6Wu+~|Y
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。 X?.bE!3=
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 TUEEwDK-
B:right outer join: '.@R_sj
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。 j]<T\O>t>
C:full outer join: 0\jOg
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。 3Fn26Rij
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二、提升 K`FgU7g{
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^[CD- #
法一:select * into b from a where 1<>1 !DCJ2h%E[_
法二:select top 0 * into b from a m=S[Y^tR
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) u
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insert into b(a, b, c) select d,e,f from b; O`dob&C
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) :u{0M&
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 zux+ooU
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8y!fqXm%)
4、说明:子查询(表名1:a 表名2:b) N)h>Ie
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) @X/S
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5、说明:显示文章、提交人和最后回复时间 l#o43xr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Em@h5V
6、说明:外连接查询(表名1:a 表名2:b) K.R2)o`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }FMl4 _}u
7、说明:在线视图查询(表名1:a ) IO xj$ ?%l
select * from (SELECT a,b,c FROM a) T where t.a > 1; -&kQlr
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 KF'H|)!K
select * from table1 where time between time1 and time2 *4qsM,t
select a,b,c, from table1 where a not between 数值1 and 数值2 -H`G6oMOO
9、说明:in 的使用方法 R\:C|/6f
select * from table1 where a [not] in ('值1','值2','值4','值6') [ylGNuy
10、说明:两张关联表,删除主表中已经在副表中没有的信息 VSZ 6;&2^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RQ{w`>K
11、说明:四表联查问题: S/d})8~.
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 ..... Xt=&
12、说明:日程安排提前五分钟提醒 i&>,aiH@
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 gH\r# wy|
13、说明:一条sql 语句搞定数据库分页 0 \LkJ*i
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 =pcj{B{qa
14、说明:前10条记录 >Fld7;L?<
select top 10 * form table1 where 范围 Mn~A;=%qF
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.) !nj%n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) \MtiLaI"
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 ~~zw[#'
(select a from tableA ) except (select a from tableB) except (select a from tableC) ! qcu-d5b
17、说明:随机取出10条数据 B0z.s+.
select top 10 * from tablename order by newid() .3|9 ~]
18、说明:随机选择记录 kFM'?L&
select newid() {|xwvTlJ
19、说明:删除重复记录 qW7"qw=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) NTL#!
20、说明:列出数据库里所有的表名 m4Wn$Z
select name from sysobjects where type='U' E}@8sY L
21、说明:列出表里的所有的 f/;\/Q[Z7
select name from syscolumns where id=object_id('TableName') 45MK|4\Y_
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 t48(GKF
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type {C]M]b*F6(
显示结果: 4rM77Uw>
type vender pcs I9F[b#'Pn
电脑 A 1 DJQ]NY|
电脑 A 1 1~ SY
光盘 B 2 N@MeaO
光盘 A 2 GPR`=]n& &
手机 B 3 3^Yk?kFE
手机 C 3 \;7DS:d@
23、说明:初始化表table1 FOk @W&
TRUNCATE TABLE table1 LDBR4@V
24、说明:选择从10到15的记录 4(aesZ8h
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (C-z8R
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三、技巧 ZHC sv]l
1、1=1,1=2的使用,在SQL语句组合时用的较多 3K?0PRg
"where 1=1" 是表示选择全部 "where 1=2"全部不选, .@6]_h;
如: +rT(
if @strWhere !='' u4<r$[]V
begin _).'SU)>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere xu:m~8%
end ?Nh%!2n
else tt^ze|*&t
begin 34oLl#q*
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $k`8Zx w
end -8tA~;p
我们可以直接写成 z'qVEHc)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9iF e^^<ss
2、收缩数据库 i`>X5Da5
--重建索引 9#iDrZW
DBCC REINDEX sN
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DBCC INDEXDEFRAG ^mum5j
--收缩数据和日志 Vd?v"2S(9
DBCC SHRINKDB .d"+M{I
DBCC SHRINKFILE oba*w;
3、压缩数据库 ^z^>]Qd
dbcc shrinkdatabase(dbname) }=|ZEhtOp
4、转移数据库给新用户以已存在用户权限 {;4PP463
exec sp_change_users_login 'update_one','newname','oldname' xF/D YXC{8
go lXPn]iLJ
5、检查备份集 4 P;O8KA5y
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b{I`$E<[
6、修复数据库 [*vN`AfE
ALTER DATABASE [dvbbs] SET SINGLE_USER 1}BNG ,n
GO *(`.h\+
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AfEEYP)N
GO +zD'r5
ALTER DATABASE [dvbbs] SET MULTI_USER x5|v#
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GO ;Bb5KD
7、日志清除 vUK>4^{J5
SET NOCOUNT ON <kSaSW
DECLARE @LogicalFileName sysname, h]Oplp4\W
@MaxMinutes INT, w3w*"M
@NewSize INT gr?pvf!I
USE tablename -- 要操作的数据库名 @
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 'sF563kE
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d>`(.qvxR
@NewSize = 1 -- 你想设定的日志文件的大小(M) if}]8
-- Setup / initialize rl^LSz
DECLARE @OriginalSize int H n!vTB
SELECT @OriginalSize = size h(8;7}K
FROM sysfiles o3yqG#dA
WHERE name = @LogicalFileName (7b_g6>:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ]-'9|N*}l
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + spx;QLo
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 2SJh6U
FROM sysfiles %^l&fM*
WHERE name = @LogicalFileName u}1vn} F{
CREATE TABLE DummyTrans )/Xrhhx
(DummyColumn char (8000) not null) \!QF9dP4
DECLARE @Counter INT, =Yj[MVn
@StartTime DATETIME, z{g<y^Im+E
@TruncLog VARCHAR(255) I7PWOd
SELECT @StartTime = GETDATE(), 5tU"|10m3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5)zB/Ta<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) nTU~M~gky
EXEC (@TruncLog) ?03Zy3/
-- Wrap the log if necessary. 2jZ}VCzRG
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 48g^~{T4O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^.C X6%
AND (@OriginalSize * 8 /1024) > @NewSize m[{&xF|_
BEGIN -- Outer loop. DP_Pqn8p&M
SELECT @Counter = 0 iFCH$!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I|IlFu?O=
BEGIN -- update (A'q@-XQ
INSERT DummyTrans VALUES ('Fill Log') <e&QTyb
DELETE DummyTrans aTh%oBrtP
SELECT @Counter = @Counter + 1 s~$4bN>LD
END (YJAT
EXEC (@TruncLog) #=H}6!18
END Zax]i,Bx
SELECT 'Final Size of ' + db_name() + ' LOG is ' + -b)zira
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,:(leWeA9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' *wB-lg7%
FROM sysfiles ,A!e"=HF
WHERE name = @LogicalFileName b<(UmRxx3
DROP TABLE DummyTrans %B&?D@
SET NOCOUNT OFF ePpK+E[0Z
8、说明:更改某个表 ~9 WJrRWB
exec sp_changeobjectowner 'tablename','dbo' ,Q#tA|:8j
9、存储更改全部表 '<=MhNh\
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch gqD^Bs'VF
@OldOwner as NVARCHAR(128), fF>qU-
@NewOwner as NVARCHAR(128) YaZt+WA
AS |~uzQU7
DECLARE @Name as NVARCHAR(128) PBs<8xBx^
DECLARE @Owner as NVARCHAR(128) g**%J Xo
DECLARE @OwnerName as NVARCHAR(128) *z"1MU
DECLARE curObject CURSOR FOR e6i./bf3
select 'Name' = name, y}-S~Ov>I
'Owner' = user_name(uid) '>|*j"jv-
from sysobjects ,N7l/6
where user_name(uid)=@OldOwner ;vc lAsJ
order by name ~R@m!'Ik
OPEN curObject :/[YY?pg-
FETCH NEXT FROM curObject INTO @Name, @Owner N^yO- xk
WHILE(@@FETCH_STATUS=0) KHus/ M&0
BEGIN @*"<U]
if @Owner=@OldOwner q3-;}+
begin /^33 e+j
set @OwnerName = @OldOwner + '.' + rtrim(@Name) D'[P,v;Q
exec sp_changeobjectowner @OwnerName, @NewOwner _Q}RElA
end Px7g\[]
-- select @name,@NewOwner,@OldOwner inv{dg/2
FETCH NEXT FROM curObject INTO @Name, @Owner /9+A97{
END A Wh*<H
close curObject lcT+$4zk.
deallocate curObject TnBG MI,g'
GO a H|OA\<
10、SQL SERVER中直接循环写入数据 K@sP~('
declare @i int _{`'{u
set @i=1 )]b@eGNGj
while @i<30 K# i*9sM
begin NVA`t]gn
insert into test (userid) values(@i)
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set @i=@i+1 y5Wqu9C\Io
end 0"<;You
小记存储过程中经常用到的本周,本月,本年函数 YTjuSV
Dateadd(wk,datediff(wk,0,getdate()),-1) CAFE}|
Dateadd(wk,datediff(wk,0,getdate()),6) 7YXXkdgbd
Dateadd(mm,datediff(mm,0,getdate()),0) 'oiD#\t4
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,6orB}w?z
Dateadd(yy,datediff(yy,0,getdate()),0) d! QD vO
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9 QCpXy
上面的SQL代码只是一个时间段 zj$_iB`9
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) gjegzKU
就是表示本周时间段. ;p#Z :6
下面的SQL的条件部分,就是查询时间段在本周范围内的: -6~dJTm[t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rI^~9Rz
而在存储过程中 aC8,Y$>?E`
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) N]s7/s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) vzyI::f?