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。 &!3=eVg
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一、基础 @
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1、说明:创建数据库 KJwkkCE/=
CREATE DATABASE database-name I]`>m3SJ
2、说明:删除数据库 ~[i,f0O,
drop database dbname CMIjc(m
3、说明:备份sql server COw]1R
--- 创建 备份数据的 device 9GdrJ~h
USE master S!GjCog^J
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' TXi$Q%0W
--- 开始 备份 *XmOWV2Y_
BACKUP DATABASE pubs TO testBack +|OkT
4、说明:创建新表 0 mWfR8h0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ] =jnt
根据已有的表创建新表: 3:rH1vG.m
A:create table tab_new like tab_old (使用旧表创建新表) Qhnz7/a9
B:create table tab_new as select col1,col2... from tab_old definition only >8V;:(nt
5、说明:删除新表 .,K?(O4AY
drop table tabname Qr;es,f
6、说明:增加一个列 "Yn<]Pa_
Alter table tabname add column col type 62}bs/%
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。
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7、说明:添加主键: Alter table tabname add primary key(col) JlF0 L%Rc
说明:删除主键: Alter table tabname drop primary key(col) %<e\s6|P:
8、说明:创建索引:create [unique] index idxname on tabname(col....) HRx%m1H
删除索引:drop index idxname BEM+FG
注:索引是不可更改的,想更改必须删除重新建。 tIb?23K0
9、说明:创建视图:create view viewname as select statement T[=XGAJ
删除视图:drop view viewname _9Kdcoh
10、说明:几个简单的基本的sql语句 hnM|=[wM
选择:select * from table1 where 范围 O\L(I079
插入:insert into table1(field1,field2) values(value1,value2) #ZIV>(Q\H
删除:delete from table1 where 范围 N1Y*IkW"
更新:update table1 set field1=value1 where 范围 VwoCRq*
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! kNW&rg
排序:select * from table1 order by field1,field2 [desc] t%Z_*mIfmE
总数:select count as totalcount from table1 ??rx\*,C</
求和:select sum(field1) as sumvalue from table1 ,z)7rU`
平均:select avg(field1) as avgvalue from table1 @T1/S&F=
最大:select max(field1) as maxvalue from table1 i\B>J?Q\
最小:select min(field1) as minvalue from table1 twx8TQ9
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11、说明:几个高级查询运算词 \PzC:H
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A: UNION 运算符 `"m"qUd
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。 p]:~z|.Ba
B: EXCEPT 运算符 g~%=[1
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。 O'm&S?>
C: INTERSECT 运算符 @]dN
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。 +*g[hRw[
注:使用运算词的几个查询结果行必须是一致的。 5.xvOi|.
12、说明:使用外连接 <27B*C M
A、left outer join: h^$>{0"
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。 dH!k{3bL
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 @6i^wC
B:right outer join: VVJhQ bP
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。 C9Fc(Y?_
C:full outer join: G#Z%jO-XN
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#| P-^
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二、提升 2?ZHWS>U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) lw? f2_fi
法一:select * into b from a where 1<>1 w"-bO ~5h
法二:select top 0 * into b from a V/|Ln*rm
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) t9m:E
insert into b(a, b, c) select d,e,f from b; E[LXZh
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) gi:;{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ih`n:aA
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bqf=;N vog
4、说明:子查询(表名1:a 表名2:b) X8bo?0
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) ~m
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5、说明:显示文章、提交人和最后回复时间 V:!fe+Er
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b h|%d=`P,
6、说明:外连接查询(表名1:a 表名2:b) itD1r?O{pV
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2=!/)hw}
7、说明:在线视图查询(表名1:a ) n=t%,[Op
select * from (SELECT a,b,c FROM a) T where t.a > 1; *NDLGdQqz
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{=-#9-4
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select * from table1 where time between time1 and time2 Q%QpG)E
select a,b,c, from table1 where a not between 数值1 and 数值2 nI.#A
9、说明:in 的使用方法 rN{&$+"2
select * from table1 where a [not] in ('值1','值2','值4','值6') +U+c]Xgt
10、说明:两张关联表,删除主表中已经在副表中没有的信息 a|5GC pp
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /D 8cJgH-
11、说明:四表联查问题: jzEimKDE's
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Y!o@"Ct
12、说明:日程安排提前五分钟提醒 2Pi}<pG~
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 5jy>)WqK
13、说明:一条sql 语句搞定数据库分页 QsDab4
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 )J (ekfM
14、说明:前10条记录 sj. eJX"z
select top 10 * form table1 where 范围 Um15@p;
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) :!tQqy2
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5qG7LO.
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 X/i8$yqv
(select a from tableA ) except (select a from tableB) except (select a from tableC) zK:/
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17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() gNLjk4H,S[
18、说明:随机选择记录 xvp{F9~qT
select newid() # JuO
19、说明:删除重复记录 uVu`TgbZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ]pb;q(?^
20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' LC[,K
21、说明:列出表里的所有的 0<v~J9i
select name from syscolumns where id=object_id('TableName') )zUV6U7v
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。 = "c
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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 _E'M(.B<
显示结果: uLhamE)
type vender pcs Q1&: +7%
电脑 A 1 pBL{DgX
电脑 A 1 "t"dz'
光盘 B 2 ~Zaxn~u:
光盘 A 2 sur2Mw(M"
手机 B 3 yo
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手机 C 3 |[o2S9 0
23、说明:初始化表table1 r*+9<8-ZX<
TRUNCATE TABLE table1 &% M^:WT
24、说明:选择从10到15的记录 &g)
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc m(g$T
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三、技巧 HNU[W8mg8
1、1=1,1=2的使用,在SQL语句组合时用的较多 YLobBtXc9
"where 1=1" 是表示选择全部 "where 1=2"全部不选, fEQ<L!'
如: >%[(C*Cks
if @strWhere !='' ?m?e2{]u,
begin _FdWV?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }clFaT>m?
end `GPK$ue
else _/E>38G]
begin N.-Ryj&9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *[yCcqN.
end qKO\;e*
我们可以直接写成 wc__g8?'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C7+TnJ
2、收缩数据库 k9R1E/;
--重建索引 ' R=o,=
DBCC REINDEX &I!2gf
DBCC INDEXDEFRAG :hJhEQH(9
--收缩数据和日志 zo\XuoZ
DBCC SHRINKDB ?LNwr[C0
DBCC SHRINKFILE B0R[f
3、压缩数据库 WUa-hm2:
dbcc shrinkdatabase(dbname) Brpin
4、转移数据库给新用户以已存在用户权限 AQ0L9?
exec sp_change_users_login 'update_one','newname','oldname' &S|laqH
go JHO9d:{-
5、检查备份集 2d3wQ)2
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' SxH}/I|W
6、修复数据库 ,#WXAAmm
ALTER DATABASE [dvbbs] SET SINGLE_USER 3!}'A
GO !%@n067
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK zNXkdw
GO 3`e1:`Hu
ALTER DATABASE [dvbbs] SET MULTI_USER IRS^F;)
GO }qlz^s
7、日志清除 =e._b 7P
SET NOCOUNT ON R [uo:.
DECLARE @LogicalFileName sysname, ~Kb(`Px@
@MaxMinutes INT, =G=.THRUk
@NewSize INT i:[B#|%
USE tablename -- 要操作的数据库名 d1E~H]X4
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2RE }l=h5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4]dPhsey
@NewSize = 1 -- 你想设定的日志文件的大小(M) m
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-- Setup / initialize E&K8hY%5
DECLARE @OriginalSize int fp>o ^+VB
SELECT @OriginalSize = size {H>iL
FROM sysfiles B2Orw8F
WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?$s2]}v
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sPZa|AKHb
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' E RMh% C
FROM sysfiles /?J_7Lg
WHERE name = @LogicalFileName U`8)rtYw
CREATE TABLE DummyTrans ,5L&$Q6
(DummyColumn char (8000) not null) oFIs,[Go
DECLARE @Counter INT, |x kixf4zz
@StartTime DATETIME, !8A5Y[(XD
@TruncLog VARCHAR(255) H"&N<"hw
SELECT @StartTime = GETDATE(), [yVU
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <B``/EX^
DBCC SHRINKFILE (@LogicalFileName, @NewSize) u?'X%'K*
EXEC (@TruncLog) bpU^|r^W
-- Wrap the log if necessary. _D+7w'8h
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +b{h*WWdj
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {u5)zVYC,U
AND (@OriginalSize * 8 /1024) > @NewSize I}8F3_b,#
BEGIN -- Outer loop. $@#nn5^IX
SELECT @Counter = 0 gXfAz,
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `o*eL Lk
BEGIN -- update A!^,QRkRN
INSERT DummyTrans VALUES ('Fill Log') YInW)My.h
DELETE DummyTrans H[G EAQO
SELECT @Counter = @Counter + 1 j`tUx#
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END em W#ZX
EXEC (@TruncLog) R0=/
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END x208^=F\\
SELECT 'Final Size of ' + db_name() + ' LOG is ' + |ow hF
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' i$NnHj|
FROM sysfiles jgO{DNe(=
WHERE name = @LogicalFileName 67sb
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DROP TABLE DummyTrans )1]C%)zn
SET NOCOUNT OFF @rJ#Dr
8、说明:更改某个表 k~hL8ZT[
exec sp_changeobjectowner 'tablename','dbo' > voUh;L
9、存储更改全部表 4^i*1&"
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), f~U|flL^
@NewOwner as NVARCHAR(128) ~O|0.)71]
AS gT+/CVj R
DECLARE @Name as NVARCHAR(128) +_ G'FD
DECLARE @Owner as NVARCHAR(128) U
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DECLARE @OwnerName as NVARCHAR(128) N4}h_mh^'
DECLARE curObject CURSOR FOR AzQ}}A;TSx
select 'Name' = name, SBF3\
'Owner' = user_name(uid) J$P]>By5:
from sysobjects -0Q!:5EC
where user_name(uid)=@OldOwner $zbg
order by name r8>
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OPEN curObject ; 6zu!
FETCH NEXT FROM curObject INTO @Name, @Owner Df4n9m}E
WHILE(@@FETCH_STATUS=0) i &KbzOY
BEGIN |Y99s)2&N
if @Owner=@OldOwner v
EX <9
begin ]pGr'T~Gj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) n/8fv~zU
exec sp_changeobjectowner @OwnerName, @NewOwner AKWw36lm
end {C6Yr9
-- select @name,@NewOwner,@OldOwner 0FW=8hFp,
FETCH NEXT FROM curObject INTO @Name, @Owner JBg>E3*N
END [[|;Wr}2
close curObject =o-qu^T^u
deallocate curObject dG|\geD
GO UnMDdJ\
10、SQL SERVER中直接循环写入数据 LTCjw_<7
declare @i int 2Hd6
set @i=1 iN)@Cu7
while @i<30 h?O-13v
begin :,u+[0-S
insert into test (userid) values(@i) F 4hEfO3
set @i=@i+1 p;H1,E:Re#
end D\TL6"wo
小记存储过程中经常用到的本周,本月,本年函数 Op0
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Dateadd(wk,datediff(wk,0,getdate()),-1) :V"}"{(6
Dateadd(wk,datediff(wk,0,getdate()),6) jIW:O
Dateadd(mm,datediff(mm,0,getdate()),0) duqu}*Jw
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]#q dA(Kl
Dateadd(yy,datediff(yy,0,getdate()),0) E }yxF.
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) q\/|nZO4
上面的SQL代码只是一个时间段 *V\kS
Dateadd(wk,datediff(wk,0,getdate()),-1) 1jF}g`At
Dateadd(wk,datediff(wk,0,getdate()),6) 4+~+`3;~v
就是表示本周时间段. yA_d${n
下面的SQL的条件部分,就是查询时间段在本周范围内的: 0O:TKgb&C.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) )I<.DN&
而在存储过程中 Jw^+t)t
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V:+}]"yJ,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xtnB:3