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。 wCKj7y[
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一、基础 h<l1U'Bn7
1、说明:创建数据库 !0}\&<8/m
CREATE DATABASE database-name :d,^I@]
2、说明:删除数据库 sen=0SB/
drop database dbname cP>o+-)
3、说明:备份sql server rf
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--- 创建 备份数据的 device =xN= #
USE master X[3}?,aqL
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L>9R4:g
--- 开始 备份 3HC
BACKUP DATABASE pubs TO testBack *_-'/i
4、说明:创建新表 qUJ
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) IDFFc&
根据已有的表创建新表: xL
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A:create table tab_new like tab_old (使用旧表创建新表) 1DJekiWf
B:create table tab_new as select col1,col2... from tab_old definition only []pN$]+c
5、说明:删除新表 aaW]JmRb
drop table tabname zu\`1W^
6、说明:增加一个列 _lxco=qd=%
Alter table tabname add column col type P 7D!6q
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。 kU l
7、说明:添加主键: Alter table tabname add primary key(col) MgMD\
说明:删除主键: Alter table tabname drop primary key(col) k;^
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8、说明:创建索引:create [unique] index idxname on tabname(col....) /Lf6WMit
删除索引:drop index idxname mTDVlw0dh
注:索引是不可更改的,想更改必须删除重新建。 Ctu?o+^;z
9、说明:创建视图:create view viewname as select statement %&<LNEiUN
删除视图:drop view viewname b1?xeG#
10、说明:几个简单的基本的sql语句 m_NCx]#e
选择:select * from table1 where 范围 r%]Qlt~K
插入:insert into table1(field1,field2) values(value1,value2) chI.{Rj
删除:delete from table1 where 范围 ]+Ixi o
更新:update table1 set field1=value1 where 范围 HL K@xKD<
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! -G |a*^
排序:select * from table1 order by field1,field2 [desc] Sus;(3EX
总数:select count as totalcount from table1 QO;4}rq
求和:select sum(field1) as sumvalue from table1 b{7E;KyY,
平均:select avg(field1) as avgvalue from table1 )7c b6jCU
最大:select max(field1) as maxvalue from table1 X@A1#z+s0]
最小:select min(field1) as minvalue from table1 -7qIToO.
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11、说明:几个高级查询运算词 8MwK.H[U
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A: UNION 运算符 SI:ifR&T
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。 e&<yX
B: EXCEPT 运算符 \_6OC Vil
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。 2h=%K/hhY
C: INTERSECT 运算符 @ EuFJ=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。 uzr\oj+>
注:使用运算词的几个查询结果行必须是一致的。 /B3R1kNf|
12、说明:使用外连接 >h~IfZU1
A、left outer join: Rqipkx
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。 +a@GHx4-
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 j{++6<tr
B:right outer join: r),PtI0X
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。 [I*!
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C:full outer join: iP@6hG`:
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。 wucV_p.E
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二、提升 m!n/U-^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 Ut@RGg+f8
法二:select top 0 * into b from a x[_=#8~.1x
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q<vf,D@{ !
insert into b(a, b, c) select d,e,f from b; j V3)2C}
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) ;F:fM!l=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 d50Vtm\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. alMYk
4、说明:子查询(表名1:a 表名2:b) &n2e
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) +FG$x/\*0
5、说明:显示文章、提交人和最后回复时间 ed 59B)?l
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )KSoq/
6、说明:外连接查询(表名1:a 表名2:b) ={2!c0s
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "d/s5sP|S
7、说明:在线视图查询(表名1:a ) @LE[ac
select * from (SELECT a,b,c FROM a) T where t.a > 1; }Rvm &?~O
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 bp<^R
select * from table1 where time between time1 and time2 |H}sYp
select a,b,c, from table1 where a not between 数值1 and 数值2 V)M1YZV{
9、说明:in 的使用方法 zSTR^sgJ
select * from table1 where a [not] in ('值1','值2','值4','值6') 0Wvq>R.(]7
10、说明:两张关联表,删除主表中已经在副表中没有的信息 F'8T;J7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <Cpp?DW_
11、说明:四表联查问题: ~!iQ6N?PY
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 ..... S:Q! "U
12、说明:日程安排提前五分钟提醒 cc=gCE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `|O yRU"EK
13、说明:一条sql 语句搞定数据库分页 rnFM/GAy
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 le)DgIT>=
14、说明:前10条记录 _ o6G6e,
select top 10 * form table1 where 范围 OWjJxORB
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.) BG`s6aC|z<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^>&k]T`
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 WKM)*@#,
(select a from tableA ) except (select a from tableB) except (select a from tableC) u+9<&)X0
17、说明:随机取出10条数据 $P
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select top 10 * from tablename order by newid() q0mOG^
18、说明:随机选择记录 ~,6b_W p/
select newid() 4DWwbO
19、说明:删除重复记录 OKOu`Hz@
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) m*0,s
20、说明:列出数据库里所有的表名 _W!p8cB
select name from sysobjects where type='U' 5`[n8mU
21、说明:列出表里的所有的 G\gMC
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select name from syscolumns where id=object_id('TableName') :\~+#/=:
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。 CG]Sj*SA~
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 Rf %HIAVE
显示结果: NmIHYN3
type vender pcs ,{eUP0]
电脑 A 1 k,Qskd-N]
电脑 A 1 \(UKdv
光盘 B 2 R>@uY(>dJ
光盘 A 2 #.B"q:CW*P
手机 B 3 B@v\eF;
手机 C 3 q~K(]Ya/
23、说明:初始化表table1 T5Eseesp
TRUNCATE TABLE table1 g+8hp@a
24、说明:选择从10到15的记录 ~:Uwg+]j
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Pi2|
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三、技巧 N)8HR9[!
1、1=1,1=2的使用,在SQL语句组合时用的较多 cTZ.}eLh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $3+PbYY
如: 'fwU]Hm
if @strWhere !='' 'Yy&G\S
begin "%2xR[NF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [f~N_G6I^o
end Ft JjY@#
else M.}7pJ7f
begin cF T 9Lnz
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @MR?6 n*k
end !{^\1QK
我们可以直接写成 *DI)?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;)0w:Zn/[
2、收缩数据库 $.St ej1
--重建索引 {[Q0qi =
DBCC REINDEX L}{`h
DBCC INDEXDEFRAG =;~I_)Pg1
--收缩数据和日志 0IM8
DBCC SHRINKDB lVH<lp_ZtK
DBCC SHRINKFILE *y[PNqyd
3、压缩数据库 Q'B6^%:<~
dbcc shrinkdatabase(dbname) rPzQ8<
4、转移数据库给新用户以已存在用户权限 s'P( ,!f
exec sp_change_users_login 'update_one','newname','oldname' /G{_7cb
go 1MkI0OZE
5、检查备份集 }w-wSkl1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Mc sTe|X
6、修复数据库 7J$b$P0}
ALTER DATABASE [dvbbs] SET SINGLE_USER }71LLzG`/
GO =(AtfW^H
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &7?R+ZGo
GO "7%:sty
ALTER DATABASE [dvbbs] SET MULTI_USER )(Iy<Y?#
GO [^H"FA[
7、日志清除 e=P
SET NOCOUNT ON 8Q`WB0E<|
DECLARE @LogicalFileName sysname, m,LG=s
@MaxMinutes INT, 1-SVCk
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@NewSize INT u8b2$D
USE tablename -- 要操作的数据库名 "GT4s?6O
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =#5D(0Ab
@MaxMinutes = 10, -- Limit on time allowed to wrap log. CCijf]+
@NewSize = 1 -- 你想设定的日志文件的大小(M) H!e 3~+)
-- Setup / initialize 6x{<e4<n
DECLARE @OriginalSize int VUU]Pu &
SELECT @OriginalSize = size }SyxPXs
FROM sysfiles rk2xKm^w
WHERE name = @LogicalFileName EER`?Sa(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + lB8il2&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ajhEL?%D
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' igf)Hb;5
FROM sysfiles QA!_} N4n
WHERE name = @LogicalFileName UK#&lim
CREATE TABLE DummyTrans 84zTCX
(DummyColumn char (8000) not null) }`VDD?M
DECLARE @Counter INT, zkM"cb13q/
@StartTime DATETIME, FwKj+f"
@TruncLog VARCHAR(255) |C \}P
SELECT @StartTime = GETDATE(), =%)+%[wv
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' U09.Y
DBCC SHRINKFILE (@LogicalFileName, @NewSize) co 4h*?q
EXEC (@TruncLog) A?5E2T1L%.
-- Wrap the log if necessary. :S@1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ge3sU5iZ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) T<yP* b2E
AND (@OriginalSize * 8 /1024) > @NewSize Rn%N&1
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BEGIN -- Outer loop. ;.sl*q1A
SELECT @Counter = 0 }0hL~i
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) <<A`aU^fX
BEGIN -- update IHfzZHy
INSERT DummyTrans VALUES ('Fill Log') S&C1 TC
DELETE DummyTrans ` >!n
SELECT @Counter = @Counter + 1 3q[WHwmm
END v
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EXEC (@TruncLog) 6Z?j AXGSq
END `[#x_<\t
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v;#=e$%}MO
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?{"mP 'dD
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' b<I9 MR
FROM sysfiles +Z2MIC|Ud
WHERE name = @LogicalFileName PALl sGlf
DROP TABLE DummyTrans inPJ2uBD\^
SET NOCOUNT OFF )Ag/Qep
8、说明:更改某个表 3Rg}+[b
exec sp_changeobjectowner 'tablename','dbo' 5pNY)>]t=
9、存储更改全部表 V5"CSMe
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !
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@OldOwner as NVARCHAR(128), ?i\B^uB
@NewOwner as NVARCHAR(128) BIaDY<j90
AS WzW-pV]
DECLARE @Name as NVARCHAR(128) Uv_N x10
DECLARE @Owner as NVARCHAR(128) hli|B+:m"
DECLARE @OwnerName as NVARCHAR(128) $m1<i?'m
DECLARE curObject CURSOR FOR -37a.
select 'Name' = name, 5lKJll^2:
'Owner' = user_name(uid) _,Fny_u=;
from sysobjects ~pk(L[G
where user_name(uid)=@OldOwner j83? m
order by name wyx(FinIH
OPEN curObject J`M&{UP
FETCH NEXT FROM curObject INTO @Name, @Owner C;AA/4Ib
WHILE(@@FETCH_STATUS=0) 8GPIZh'0h
BEGIN `i,_aFB|
if @Owner=@OldOwner =+5,B\~q@C
begin }g+;y
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5 /",<1
exec sp_changeobjectowner @OwnerName, @NewOwner Z.L?1V8Q1
end C<^YVeG
-- select @name,@NewOwner,@OldOwner yn
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FETCH NEXT FROM curObject INTO @Name, @Owner os3 8u!3-
END kEeo5XN
close curObject 9 A,Z|q/z5
deallocate curObject Mvj;ic6iK
GO uy _wp^
10、SQL SERVER中直接循环写入数据 *F^wtH`
declare @i int xVB;s.'!
set @i=1 I7+9~5p
while @i<30 h<<>3 A
begin m .IU ;cR
insert into test (userid) values(@i) lLq<xf
set @i=@i+1 6\7ncFO3
end i=a-<A5x
小记存储过程中经常用到的本周,本月,本年函数 Jo(`zuLJ
Dateadd(wk,datediff(wk,0,getdate()),-1) }_tl n
Dateadd(wk,datediff(wk,0,getdate()),6) -Lu)'+
Dateadd(mm,datediff(mm,0,getdate()),0) <Tw>|cFT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <F7kh[L_x
Dateadd(yy,datediff(yy,0,getdate()),0) in <(g@Zg
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) v dbO(
上面的SQL代码只是一个时间段 GY3 Wj
Dateadd(wk,datediff(wk,0,getdate()),-1) 8kE]_t
Dateadd(wk,datediff(wk,0,getdate()),6) 5la>a}+!!h
就是表示本周时间段. YG:3Fhx0~
下面的SQL的条件部分,就是查询时间段在本周范围内的: $w)~O<_U
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) W/z7"#
而在存储过程中 bUV >^d
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) z't??6
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) J2q,7wI#