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。 %%6('wi
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一、基础 s2~dmZ_B|_
1、说明:创建数据库 @88i/ Z_
CREATE DATABASE database-name YS~t d+*
2、说明:删除数据库 "Q{~Bj~
drop database dbname 'V#ew\
3、说明:备份sql server KVxb"|[
--- 创建 备份数据的 device (PcK(C!}=\
USE master 493i*j5r)l
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 4iqmi<[("
--- 开始 备份 {yMA7W7]
BACKUP DATABASE pubs TO testBack |SKG4_wGe
4、说明:创建新表 z \>X[yNpA
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) J"/z?!)IB
根据已有的表创建新表: PMs_K"-K
A:create table tab_new like tab_old (使用旧表创建新表) j#t8Krd] "
B:create table tab_new as select col1,col2... from tab_old definition only +wozjjc
5、说明:删除新表 x}'4^Cv
drop table tabname :xS&Y\ry
6、说明:增加一个列 siYRRr
Alter table tabname add column col type S.|kg2
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。 AYIz;BmWy
7、说明:添加主键: Alter table tabname add primary key(col) <[:7#Yo
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说明:删除主键: Alter table tabname drop primary key(col) 2pa3}6P+
8、说明:创建索引:create [unique] index idxname on tabname(col....) PlH`(n#
删除索引:drop index idxname 3n(gfQo-o
注:索引是不可更改的,想更改必须删除重新建。 ggc?J<Dv
9、说明:创建视图:create view viewname as select statement w/5^R
删除视图:drop view viewname y*h1W4:^-
10、说明:几个简单的基本的sql语句 #Jz&9I<OKx
选择:select * from table1 where 范围 86fK=G:>
插入:insert into table1(field1,field2) values(value1,value2) +'KE T,
删除:delete from table1 where 范围 C_cs(}wi
更新:update table1 set field1=value1 where 范围 cvE.r330|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! qlITQKGG
排序:select * from table1 order by field1,field2 [desc] :5<9/
总数:select count as totalcount from table1 [ 5
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求和:select sum(field1) as sumvalue from table1 cO+Xzd;838
平均:select avg(field1) as avgvalue from table1 V<ApHb
最大:select max(field1) as maxvalue from table1 fGf-fh;s
最小:select min(field1) as minvalue from table1 <W59mweW#5
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11、说明:几个高级查询运算词 \UqS -j|
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A: UNION 运算符 aq+IC@O
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\~ KVn
B: EXCEPT 运算符 ITIj=!F*
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。 |W*@}D
C: INTERSECT 运算符 %=9yzIjbAt
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。 5%?b5(mnD
注:使用运算词的几个查询结果行必须是一致的。 D&l,SD
12、说明:使用外连接 UlNfI}#X
A、left outer join:
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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。 B$TChc3B
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @ Rx6 >52>
B:right outer join: |4S?>e
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 @D~+D@i$TW
C:full outer join:
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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。 9/1+BQ
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二、提升 J4v0O="
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ct}%Mdg
法一:select * into b from a where 1<>1 qJ+52U|z
法二:select top 0 * into b from a (;pi"/x[
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Zfy~mv$
insert into b(a, b, c) select d,e,f from b; zf3:<CRX5
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) Np<s[dQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mvq7G
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P B(
4、说明:子查询(表名1:a 表名2:b) ]osx.
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) ]TBtLU3
5、说明:显示文章、提交人和最后回复时间 Bug}^t{M
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b YYE8/\+B.
6、说明:外连接查询(表名1:a 表名2:b) Z@,PZ
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {!}F
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7、说明:在线视图查询(表名1:a ) w^])(
select * from (SELECT a,b,c FROM a) T where t.a > 1; qfGtUkSSb
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 QGr\I/Y
select * from table1 where time between time1 and time2 3g0u#t{
select a,b,c, from table1 where a not between 数值1 and 数值2 HS\3)Ooj>
9、说明:in 的使用方法 6b]1d04hT
select * from table1 where a [not] in ('值1','值2','值4','值6') B3dA%\'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /MKNv'5&!%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0SMQDs5j
11、说明:四表联查问题: ,9Z2cgXwJ
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 ..... nx-1*
12、说明:日程安排提前五分钟提醒 O~h94 B`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (D>y6r>r
13、说明:一条sql 语句搞定数据库分页 Ni!;-,H+E
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 k%]DT.cE
14、说明:前10条记录 dv'E:R(a
select top 10 * form table1 where 范围 xaWGa1V'z
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.) h41$|lonU%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Z>x7|Q3CX
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 m0|Ae@g~3
(select a from tableA ) except (select a from tableB) except (select a from tableC) @)vy'qP d
17、说明:随机取出10条数据 ,](v?v.[4
select top 10 * from tablename order by newid() Jh$"f r3
18、说明:随机选择记录 j,=*WG
select newid() ?""\
19、说明:删除重复记录 F_nZvv[H?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) tE]5@b,R
20、说明:列出数据库里所有的表名 uNe}"hs
select name from sysobjects where type='U' qDRNtFa
21、说明:列出表里的所有的 \D,M2vC~G
select name from syscolumns where id=object_id('TableName') ]yAEjn9cN
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。 (_w
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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 r(:
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显示结果:
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type vender pcs \E$1lc
电脑 A 1 ls"b#eFC#
电脑 A 1 %2Epgh4?
光盘 B 2 5pRY&6So
光盘 A 2 ua`6M
手机 B 3 z;dcAdz9
手机 C 3 k,,!P""
23、说明:初始化表table1 gX@nPZjg
TRUNCATE TABLE table1 psIkG0
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24、说明:选择从10到15的记录 pbDw Lo]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc xH<'GB)
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三、技巧 D=r-
1、1=1,1=2的使用,在SQL语句组合时用的较多 50LHF%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, A&<?
如: )=jT_?9b
if @strWhere !='' CAUijMI@
begin T8$%9&j!UE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere (R_CUH
end ?R;nL{
else zmf"I[)
begin /Hv*K&}M
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,IIZXl@
end i8Fs0U4"
我们可以直接写成 5<89Af&&K8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^|wT_k\
2、收缩数据库 f49"pTw7
--重建索引 `$S^E !=
DBCC REINDEX +D:83h{
DBCC INDEXDEFRAG bh6d./
--收缩数据和日志 lPY@{1W
DBCC SHRINKDB ,b4):{
DBCC SHRINKFILE S:ls[9G[3
3、压缩数据库 9i0M/vx
dbcc shrinkdatabase(dbname) =op`fn%
4、转移数据库给新用户以已存在用户权限 tC&fAE:S
exec sp_change_users_login 'update_one','newname','oldname' u3 ]Uxy
go [{`)j
5、检查备份集 Bul.RCP'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' sFLcOPj-%
6、修复数据库 B?SNea,I4
ALTER DATABASE [dvbbs] SET SINGLE_USER LeY+p]n~
GO r4E`'o[
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK FZiZg;
GO ( %[Tk[
ALTER DATABASE [dvbbs] SET MULTI_USER ~xS@]3n=
GO jCzGus!rM
7、日志清除 RCI4~q
SET NOCOUNT ON aH%ZetLNJ
DECLARE @LogicalFileName sysname, 1Gsw-a;a
@MaxMinutes INT, !:(C"}5wM
@NewSize INT np\st7&f6
USE tablename -- 要操作的数据库名 "YJ[$TG
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 nO~b=qO
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |GtY*|
@NewSize = 1 -- 你想设定的日志文件的大小(M) /D0RC
-- Setup / initialize 8;TAb.r
DECLARE @OriginalSize int 75ZH
SELECT @OriginalSize = size cVp[ Z#B
FROM sysfiles H+a~o=/cR
WHERE name = @LogicalFileName k({2yc#RD&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2B-.}OJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + m}98bw
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
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FROM sysfiles 4E2yH6l
WHERE name = @LogicalFileName ejVdxVr \7
CREATE TABLE DummyTrans 5MxH)~VQoM
(DummyColumn char (8000) not null) WSQ[.C
DECLARE @Counter INT, {O)YwT$`
@StartTime DATETIME, ]}kI)34/
@TruncLog VARCHAR(255) \yNQQ$B
SELECT @StartTime = GETDATE(), ,eDD:#)$}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' wX ,h<\7
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {LP
b))
EXEC (@TruncLog) AH^e]<2-
-- Wrap the log if necessary. dIk'pA^d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6mCq/$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :X_CFW
AND (@OriginalSize * 8 /1024) > @NewSize F?z<xL@
BEGIN -- Outer loop. s2%V4yy%
SELECT @Counter = 0 Z?17Pu'Dp
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 0#QKVZq2>
BEGIN -- update d<x1*a
INSERT DummyTrans VALUES ('Fill Log') ;hwzYXWF
DELETE DummyTrans 3cqQL!Gm
SELECT @Counter = @Counter + 1 i'HPRY
END :[xvlW29
EXEC (@TruncLog) F.<L>
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END bpW!iY/q3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + zOB !(R
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + pz7H To;p
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' I5qM.@%zB
FROM sysfiles Pt)S;6j
WHERE name = @LogicalFileName ~wOTjz
DROP TABLE DummyTrans %:3'4;jh%
SET NOCOUNT OFF ?6f7ld5
8、说明:更改某个表 03EV%Vc
exec sp_changeobjectowner 'tablename','dbo' |jT2W
9、存储更改全部表 %x2uP9
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch C/G]v*MBQ
@OldOwner as NVARCHAR(128),
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@NewOwner as NVARCHAR(128) f2yq8/J8.
AS 9_ZBV{
DECLARE @Name as NVARCHAR(128) llq*T"7
DECLARE @Owner as NVARCHAR(128) ,}0$Tv\1
DECLARE @OwnerName as NVARCHAR(128) #{$1z;i?f
DECLARE curObject CURSOR FOR sw$2d
select 'Name' = name, H\E7o"m
'Owner' = user_name(uid) jY/ARBC}H
from sysobjects URA0ey`
where user_name(uid)=@OldOwner ! Z;T-3^.
order by name U\jb"
OPEN curObject Fu7M0X'p
FETCH NEXT FROM curObject INTO @Name, @Owner fN)x#?
WHILE(@@FETCH_STATUS=0) o@W_ai_
BEGIN {~N3D4n^
if @Owner=@OldOwner H z@h0+h
begin IkDiT63]I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *KJB>W%@uM
exec sp_changeobjectowner @OwnerName, @NewOwner E9+ HS
end sWHyL(C@
-- select @name,@NewOwner,@OldOwner KVR~jF%
FETCH NEXT FROM curObject INTO @Name, @Owner <sX VW
END K]/Od
close curObject h?Nek+1'
deallocate curObject *%!M4&
GO \\:|Odd
10、SQL SERVER中直接循环写入数据 &nY;=Hv`WY
declare @i int r\2vl8X~
set @i=1 5Fbs
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while @i<30 2q PhLCeZ
begin u5Up&QE!>q
insert into test (userid) values(@i) 2-dh;[4
set @i=@i+1 +q{[\#t5
end Vr=OYI'A
小记存储过程中经常用到的本周,本月,本年函数 PD6_)PXn
Dateadd(wk,datediff(wk,0,getdate()),-1) 6e&$l-
Dateadd(wk,datediff(wk,0,getdate()),6) "AC^ rz~U
Dateadd(mm,datediff(mm,0,getdate()),0) Qz,|mo+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) w^q7n
Dateadd(yy,datediff(yy,0,getdate()),0) s5D:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) G:IP? z]
上面的SQL代码只是一个时间段 j 1*f]va
Dateadd(wk,datediff(wk,0,getdate()),-1) `Ye8
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Dateadd(wk,datediff(wk,0,getdate()),6) 'T,c.Vj)
就是表示本周时间段. h|bT)!|
下面的SQL的条件部分,就是查询时间段在本周范围内的: G.\l qYrXU
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6w|J-{2
而在存储过程中 kWhr1wR1
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) TL0[@rr4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Ws I>n