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。 V?{d<Ng~J
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一、基础 A,~3oQV
1、说明:创建数据库 B7%,D}
CREATE DATABASE database-name ,!:c6F+
2、说明:删除数据库 Tv ``\<
drop database dbname hi8q?4jE
3、说明:备份sql server c!Hz'W
--- 创建 备份数据的 device Bz]tKJ
USE master )4g_S?l=
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' fd)8lK[KJ"
--- 开始 备份 {T4_Xn -I
BACKUP DATABASE pubs TO testBack /@9Q:'P
4、说明:创建新表 7
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) :5k* kx#y
根据已有的表创建新表: q[$>\Nfg>B
A:create table tab_new like tab_old (使用旧表创建新表) ytcLx77`:
B:create table tab_new as select col1,col2... from tab_old definition only <XeDJ8
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5、说明:删除新表 N^;lp<{6?
drop table tabname HWjJ.;k}a
6、说明:增加一个列 ^z
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Alter table tabname add column col type !<w6j-S
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。 S@qPf0dL<
7、说明:添加主键: Alter table tabname add primary key(col) K"!rj.Da
说明:删除主键: Alter table tabname drop primary key(col) &f.5:u%{b
8、说明:创建索引:create [unique] index idxname on tabname(col....) F-;J N
删除索引:drop index idxname O/~T+T%
注:索引是不可更改的,想更改必须删除重新建。 FQWjL>NB
9、说明:创建视图:create view viewname as select statement UFB|IeX?q
删除视图:drop view viewname IL@yGuO,
10、说明:几个简单的基本的sql语句 !:+U-mb*
选择:select * from table1 where 范围 ,HjJ jpE
插入:insert into table1(field1,field2) values(value1,value2) P
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删除:delete from table1 where 范围 }i+C)VUX
更新:update table1 set field1=value1 where 范围 {Ydhplg{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! db )2>
排序:select * from table1 order by field1,field2 [desc] =D(a~8&,
总数:select count as totalcount from table1 rc=E%Qv%?
求和:select sum(field1) as sumvalue from table1 392V\qtS
平均:select avg(field1) as avgvalue from table1 (PpY*jKR
最大:select max(field1) as maxvalue from table1 x?Sx cQP
最小:select min(field1) as minvalue from table1 aCU[9Xr?
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11、说明:几个高级查询运算词 Q YA4C1h'
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A: UNION 运算符 X_PzK'#m
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。 DwBe_h .
B: EXCEPT 运算符 Q=Q+*oog
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。 d!I%AlV
C: INTERSECT 运算符 `q}D#0
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。 LW=qX%o{
注:使用运算词的几个查询结果行必须是一致的。 =9&2udV1
12、说明:使用外连接 JQ+Mg&&Q
A、left outer join: 48p3m)5
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。 e{8C0=
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 V
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B:right outer join: ?c.\\2>|F
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。 HVM%B{(
C:full outer join: W8<QgpV*
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。 |6AR!
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二、提升 ZRhk2DA#FF
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )=)N9C Ry
法一:select * into b from a where 1<>1 {tVA(&\<
法二:select top 0 * into b from a jnV#Q
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) H;=yR]E
insert into b(a, b, c) select d,e,f from b; 8i6iynR
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<1$zQY!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 u/tJ])~@
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. l<_v3/3
4、说明:子查询(表名1:a 表名2:b) !+$qSD,%x
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) hx^@aI
5、说明:显示文章、提交人和最后回复时间 +HE,Q6-A
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 88u[s@
6、说明:外连接查询(表名1:a 表名2:b) thPAD+u.3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #|\|G3Si
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7、说明:在线视图查询(表名1:a ) WGV]O|
select * from (SELECT a,b,c FROM a) T where t.a > 1; {Lju7'5L
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 wW TuEM
select * from table1 where time between time1 and time2 ;)rhx`"n
select a,b,c, from table1 where a not between 数值1 and 数值2 X}B]5
9、说明:in 的使用方法 &Zz&VwWR
select * from table1 where a [not] in ('值1','值2','值4','值6') IiKU=^~w
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B)k/]vz)*D
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !5 S#
11、说明:四表联查问题: e\z,^
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 0Y`+L6&UX
12、说明:日程安排提前五分钟提醒 A7QT4h&6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ufR|V-BWx
13、说明:一条sql 语句搞定数据库分页 d Np%=gIj
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 hbXm Ist
14、说明:前10条记录 li3X}
select top 10 * form table1 where 范围 (fc_V[(m"
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) UHJro9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ZV Ko$q:F
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 65B&>`H~
(select a from tableA ) except (select a from tableB) except (select a from tableC) Ds=d~sN u
17、说明:随机取出10条数据 w[2E:Nj
select top 10 * from tablename order by newid() 4gZ R!J
18、说明:随机选择记录 E2hML
select newid() V^(W)\
19、说明:删除重复记录 .t^1e
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) qPu?rU{2
20、说明:列出数据库里所有的表名 W&A^.% 2l
select name from sysobjects where type='U' +fvVora
21、说明:列出表里的所有的 HmXxM:[4;
select name from syscolumns where id=object_id('TableName') pDC`Fi
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。 L `2{H%J`
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 d3oRan}z
显示结果: )m-(- I
type vender pcs } %3;j5 ;6
电脑 A 1 9'X "a
电脑 A 1 N#J8 4i;ry
光盘 B 2 l2#~
光盘 A 2 6hcs)X7m
手机 B 3 #E4oq9{0*W
手机 C 3 Z'AjeZyyE
23、说明:初始化表table1 "<oR.f=0
TRUNCATE TABLE table1 }lk9|U#6*`
24、说明:选择从10到15的记录 pJ?y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V\Lh(zPt
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三、技巧 jxK
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1、1=1,1=2的使用,在SQL语句组合时用的较多 }m!T~XR</
"where 1=1" 是表示选择全部 "where 1=2"全部不选, rp]H&5.*
如: vSQB~Vw8t
if @strWhere !='' Vl7V?`_4
begin ^(*eo e
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )x5w`N]lm
end RG1#\d-fE
else sI)jqHZG
begin 'fb&3
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]<},[s
end 7CT446
我们可以直接写成 .j!:Hp(z}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2V @ pt
2、收缩数据库 @C'qbO{
--重建索引 nCldH|>5w
DBCC REINDEX nQw, /Lk
DBCC INDEXDEFRAG ylmVmHmc
--收缩数据和日志 * se),CP!s
DBCC SHRINKDB ~@^ pX*%i
DBCC SHRINKFILE OoOwEV2p_
3、压缩数据库 2J(,Xf
dbcc shrinkdatabase(dbname) m7,"M~\pX
4、转移数据库给新用户以已存在用户权限 m,J9:S<5;
exec sp_change_users_login 'update_one','newname','oldname' FOa2VP%
go s4 Uk5<
5、检查备份集 Si;eBPFH
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Dk~
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6、修复数据库 `C:J {`
ALTER DATABASE [dvbbs] SET SINGLE_USER )q7!CG'oY
GO f+Bv8 g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK QswFISch
GO uCFpH5>
ALTER DATABASE [dvbbs] SET MULTI_USER 'kCr1t
GO *xKY>E+
7、日志清除 R*"zLJP
SET NOCOUNT ON &'5j!
DECLARE @LogicalFileName sysname, }e1]Ib!
@MaxMinutes INT, Oi!uJofW
@NewSize INT ^O5PcV 3Eg
USE tablename -- 要操作的数据库名 ()$tP3o
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 w3Qil[rg
@MaxMinutes = 10, -- Limit on time allowed to wrap log. n\scOM)3
@NewSize = 1 -- 你想设定的日志文件的大小(M) XQ k,xQ
-- Setup / initialize B?XqH_=0L
DECLARE @OriginalSize int BfvvJh_
SELECT @OriginalSize = size G{s
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FROM sysfiles _'r&'s;<z
WHERE name = @LogicalFileName xirZ.wj W
SELECT 'Original Size of ' + db_name() + ' LOG is ' + M-f; ,>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x8rp Z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5DeAH;
FROM sysfiles mVyF M -`
WHERE name = @LogicalFileName _`]YWvh
CREATE TABLE DummyTrans K30{Fcb< h
(DummyColumn char (8000) not null) 5
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DECLARE @Counter INT, r/ LgmVRn
@StartTime DATETIME, tw]Q5:6
@TruncLog VARCHAR(255) ^X?3e1om
SELECT @StartTime = GETDATE(), c(S66lp
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >x1?t
DBCC SHRINKFILE (@LogicalFileName, @NewSize) i\P)P!
EXEC (@TruncLog) .ktyA+r8v
-- Wrap the log if necessary. SnW>`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _$qH\>se
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LT '2446
AND (@OriginalSize * 8 /1024) > @NewSize ?F%,d{^
BEGIN -- Outer loop. l:VcV
SELECT @Counter = 0 8<g9 ~L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) G
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BEGIN -- update k'{Bhi4
INSERT DummyTrans VALUES ('Fill Log') 6SD9lgF*-
DELETE DummyTrans &Sp2['a!
SELECT @Counter = @Counter + 1 }W* q
END M,9f}V)
EXEC (@TruncLog) *1b)Va8v*
END m:{IVvN_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + r`CsR0[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^5*9BwH`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ||kUi=5
FROM sysfiles |Xk>a7X
WHERE name = @LogicalFileName 39,7N2 uY
DROP TABLE DummyTrans |`6*~ciUV
SET NOCOUNT OFF H(j983
8、说明:更改某个表 0W>,RR)
exec sp_changeobjectowner 'tablename','dbo' DlbNW& V
9、存储更改全部表 w57D qG>
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch L(qQ,1VY
@OldOwner as NVARCHAR(128), r5aOQ
@NewOwner as NVARCHAR(128) *U^7MU0
AS Wi{ jC?2Q
DECLARE @Name as NVARCHAR(128) r(cd?sL96R
DECLARE @Owner as NVARCHAR(128) n[`FoY
DECLARE @OwnerName as NVARCHAR(128) /q >1X!Z
DECLARE curObject CURSOR FOR UgZuEfEGve
select 'Name' = name, N(^
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'Owner' = user_name(uid) ).1F0T
from sysobjects e47N 9&4
where user_name(uid)=@OldOwner 3rw<#t;v
order by name :HQQ8uQfb
OPEN curObject x.~A vJ
FETCH NEXT FROM curObject INTO @Name, @Owner %Y// }
WHILE(@@FETCH_STATUS=0) 1|Z!8:&pj
BEGIN .:=G=v=1
if @Owner=@OldOwner .+ g8zbD4
begin mXXU{IwUe
set @OwnerName = @OldOwner + '.' + rtrim(@Name) |.Y}2>{
exec sp_changeobjectowner @OwnerName, @NewOwner "_
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end )> |x 2q
-- select @name,@NewOwner,@OldOwner jUCrj'
FETCH NEXT FROM curObject INTO @Name, @Owner u'+;/8
END 6#/v:;bF
close curObject S4FR=QuVQC
deallocate curObject W #kOcw
GO R<n'v.~"A
10、SQL SERVER中直接循环写入数据 xF8^#J6>
declare @i int 1MnT*w
set @i=1 jou741
while @i<30 f/NfvLi(AU
begin i@p0Jnh|
insert into test (userid) values(@i) Dm0Ts~
set @i=@i+1 +:?"P<'
end wXnluE
小记存储过程中经常用到的本周,本月,本年函数 )4BLm
Dateadd(wk,datediff(wk,0,getdate()),-1) VwrHD$
Dateadd(wk,datediff(wk,0,getdate()),6) V*w~Sr%
Dateadd(mm,datediff(mm,0,getdate()),0) G :JQ_w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) of k@.TmO
Dateadd(yy,datediff(yy,0,getdate()),0) Q,m1mIf
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) w5uOkz #
上面的SQL代码只是一个时间段 2Ub!wee
Dateadd(wk,datediff(wk,0,getdate()),-1) ,4tuWO)"
Dateadd(wk,datediff(wk,0,getdate()),6) =7212('F
就是表示本周时间段. /I/gbmc)
下面的SQL的条件部分,就是查询时间段在本周范围内的: I c 2R\}q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Z0I>PBL@l
而在存储过程中 ;Wu6f"+Y#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )UgLs|G~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~SN *