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。
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一、基础 |c_qq Bd
1、说明:创建数据库 jc}G+|`
CREATE DATABASE database-name UO/sv2CN
2、说明:删除数据库 .KsR48g8
drop database dbname B/?
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3、说明:备份sql server ]Bw0Qq F#
--- 创建 备份数据的 device sDY~jP[Oa
USE master IK~&`n](>
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?$ r`T]>`2
--- 开始 备份 0XHQ5+"8
BACKUP DATABASE pubs TO testBack PNU(;&2<
4、说明:创建新表 E-e(K8R
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) U84W(X
根据已有的表创建新表: P]E-Wp'p
A:create table tab_new like tab_old (使用旧表创建新表) 5j%G7.S\
B:create table tab_new as select col1,col2... from tab_old definition only 6 SSDc/
5、说明:删除新表 f8
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drop table tabname AOf4y&B>q
6、说明:增加一个列 6*OL.~WE
Alter table tabname add column col type nB[-KS
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。 ~(5r+Z}*`
7、说明:添加主键: Alter table tabname add primary key(col) k9|5TLXq?
说明:删除主键: Alter table tabname drop primary key(col) 0D X_*f
8、说明:创建索引:create [unique] index idxname on tabname(col....) .6B\fr.za
删除索引:drop index idxname <g4}7l8
注:索引是不可更改的,想更改必须删除重新建。 .R9Z$Kbq
9、说明:创建视图:create view viewname as select statement gL; Kie6Z
删除视图:drop view viewname 4E'9;tA3l
10、说明:几个简单的基本的sql语句 "
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选择:select * from table1 where 范围 p{FI_6db
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 '`];=QY9pg
更新:update table1 set field1=value1 where 范围 H=r-f@EOrI
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 3r\8v`^>
排序:select * from table1 order by field1,field2 [desc] d|`Ll
总数:select count as totalcount from table1 l6viP}R
求和:select sum(field1) as sumvalue from table1 8xpplo8
平均:select avg(field1) as avgvalue from table1 xNP_>Qa~
最大:select max(field1) as maxvalue from table1 Uv^\[
最小:select min(field1) as minvalue from table1 6Rd4waj_,U
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11、说明:几个高级查询运算词 +Y\:Q<eMFg
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A: UNION 运算符 _GOSqu!3Y
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。 J
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B: EXCEPT 运算符 IG-\&
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。 N^^0j,
C: INTERSECT 运算符 :5d>^6eoB?
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。 K%^n.
注:使用运算词的几个查询结果行必须是一致的。 BHXi g~d
12、说明:使用外连接 OWd'z1Yl
A、left outer join: L9x-90'q,
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。 v
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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 n,la<N]
B:right outer join: Bq0 \T
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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。 /--p#G h'
C:full outer join: bOY;IB
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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。 gk ]QR.
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二、提升 gcLz}84
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 4s\spvJ
法一:select * into b from a where 1<>1 yDWIflP0;
法二:select top 0 * into b from a _|HhT^\P
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3v* ~CQy9
insert into b(a, b, c) select d,e,f from b; \P\Z<z7jy
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) cHFi(K]|1
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 "S#FI
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^?z%f_ri
4、说明:子查询(表名1:a 表名2:b) 8hRcB[F~S
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) 1MelHW
5、说明:显示文章、提交人和最后回复时间 f60w%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Iv`IJQH>
6、说明:外连接查询(表名1:a 表名2:b) Io6/Fv>!
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|RmAP;X,
7、说明:在线视图查询(表名1:a ) *Cy54Z#
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^l &lwSRVt
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 6(
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select * from table1 where time between time1 and time2 UD I{4+z
select a,b,c, from table1 where a not between 数值1 and 数值2 n:j'0WW
9、说明:in 的使用方法 HL)!p8UHJ
select * from table1 where a [not] in ('值1','值2','值4','值6') J3$>~?^1
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~lj~]j
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0D-`>_
11、说明:四表联查问题: E-LkP;
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... Obdn#Wm=
12、说明:日程安排提前五分钟提醒 f~IJ4T2#N
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )7q$PcY
13、说明:一条sql 语句搞定数据库分页 3;nOm =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 _vQ52H,
14、说明:前10条记录 9hp&HL)BOa
select top 10 * form table1 where 范围 R!nf^*~
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.) A|A~$v("R
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) z^Q'GBoBA
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 {@Wv@H+4
(select a from tableA ) except (select a from tableB) except (select a from tableC) Hxu5Dx5![
17、说明:随机取出10条数据 >A#5` $i
select top 10 * from tablename order by newid() &$"#hGg
18、说明:随机选择记录 Dc9uq5l
select newid() k.@![w\ea
19、说明:删除重复记录 cx}Yu8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) J8|MK.oD
20、说明:列出数据库里所有的表名 Daf|.5>(@
select name from sysobjects where type='U' j50vPV8m
21、说明:列出表里的所有的 MJn-] E
select name from syscolumns where id=object_id('TableName') _k84#E0
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。 &|>@K#V8-;
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 "hkcN+=
显示结果: g` rr3jP
type vender pcs =]5tYIU
电脑 A 1 ~/OY1~c
电脑 A 1 w$2q00R>
光盘 B 2 F!z0N
光盘 A 2 .ZXoRT
手机 B 3 V^~RDOSy7n
手机 C 3 g?j)p y
23、说明:初始化表table1 24sMX7Q,i
TRUNCATE TABLE table1 5Rqdo\vE
24、说明:选择从10到15的记录 Pz4#>tP
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc "k zKQ~
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三、技巧 .qBc;u
1、1=1,1=2的使用,在SQL语句组合时用的较多 K7}.# *% ~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, <'Q6\R}:vC
如: 8NN+Z<
if @strWhere !='' ]ua3I}_B6v
begin hA=uoe\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &AiAd6
end ]uXJjS f
else (qn=BPI
begin ~(kEGEF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' /ViY:-8s
end J,W<ha*
我们可以直接写成 +{UY9_~\3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere q'D Ts9Bj
2、收缩数据库 `[ZswLE
--重建索引 U%3N=M
DBCC REINDEX A;AQw
DBCC INDEXDEFRAG mxNd
--收缩数据和日志 =NB[jQ :(
DBCC SHRINKDB aNbS0R>l
DBCC SHRINKFILE /VR~E'Cy%
3、压缩数据库 ;hj lRQ\
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 fQ+whGB
exec sp_change_users_login 'update_one','newname','oldname' c3]t"TA,
go 0R
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5、检查备份集 ?kjQ_K
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^WA7X9ed
6、修复数据库 {3Inj8a=?A
ALTER DATABASE [dvbbs] SET SINGLE_USER 1U\ap{z@
GO Q%e<0t7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?m7:@GOE1
GO l9K`+c+t
ALTER DATABASE [dvbbs] SET MULTI_USER I~,.@{4
GO RpdUR*K9x
7、日志清除 YQ0#j'}/
SET NOCOUNT ON ^[<BMk
DECLARE @LogicalFileName sysname, v,4{:y]p
@MaxMinutes INT, +C~h(
@NewSize INT >Kgw2,y+
USE tablename -- 要操作的数据库名 zs$r>rlO
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 $6"sR I6u
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9A|A@E#
@NewSize = 1 -- 你想设定的日志文件的大小(M) /=2aD5r
-- Setup / initialize _p$/.~Xo9
DECLARE @OriginalSize int \o<ucp\J
SELECT @OriginalSize = size 3,PR6a,b'
FROM sysfiles mK:gj&N7X|
WHERE name = @LogicalFileName ^PG"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + O9ex=m `L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0`/G(ukO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,dC.|P' `
FROM sysfiles WJ{Iv] }9
WHERE name = @LogicalFileName 7_~ A*LM
CREATE TABLE DummyTrans d$IROZK-D
(DummyColumn char (8000) not null) NcA
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DECLARE @Counter INT, 2 6#p,P
@StartTime DATETIME, ki1(b]rf
@TruncLog VARCHAR(255) x0 j5D
SELECT @StartTime = GETDATE(), '9\cIni0
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v9(5HY
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \Vc[/Qp7Bb
EXEC (@TruncLog) rr#nBhh8
-- Wrap the log if necessary.
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired "i&)+dr-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) B{Q}^Mcxy
AND (@OriginalSize * 8 /1024) > @NewSize i/:L^SQAq
BEGIN -- Outer loop.
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SELECT @Counter = 0 G,C`+1$*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *6I$N>1
BEGIN -- update d4o
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INSERT DummyTrans VALUES ('Fill Log') (MGgr
DELETE DummyTrans J[lC$X[
SELECT @Counter = @Counter + 1 G
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END @*%3+9`yq
EXEC (@TruncLog) ?
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END Po ?MTA
SELECT 'Final Size of ' + db_name() + ' LOG is ' + N+&uR!:.C
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + zgD?e?yPO
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Q68~D.V%r
FROM sysfiles L0w6K0J4
WHERE name = @LogicalFileName vQ rxx
DROP TABLE DummyTrans FJ_JaIby
SET NOCOUNT OFF B=A!hXNa
8、说明:更改某个表 St5;X&Q
exec sp_changeobjectowner 'tablename','dbo' wFMH\a
9、存储更改全部表 ERPg TZT
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch pg{VKrT`
@OldOwner as NVARCHAR(128), F
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@NewOwner as NVARCHAR(128) pRQ7rT',v
AS TV{GHB!p"
DECLARE @Name as NVARCHAR(128) BTAbDyH5
DECLARE @Owner as NVARCHAR(128) 99yWUC,
DECLARE @OwnerName as NVARCHAR(128) 3IxC@QR
DECLARE curObject CURSOR FOR bEcs(Mc~
select 'Name' = name, |[],z 8
'Owner' = user_name(uid) t/ \S9
from sysobjects YsmRY=3
where user_name(uid)=@OldOwner UPtj@gtcY
order by name ~z^?+MgZ2
OPEN curObject I\*6
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FETCH NEXT FROM curObject INTO @Name, @Owner ("U<@~
WHILE(@@FETCH_STATUS=0) JrcbJt
BEGIN s|%R
if @Owner=@OldOwner ]>M\|,wh
begin "B'c;0@q
set @OwnerName = @OldOwner + '.' + rtrim(@Name) U["0B8
exec sp_changeobjectowner @OwnerName, @NewOwner r+#{\~r7T
end x2v0cR"KL
-- select @name,@NewOwner,@OldOwner N7?]eD
FETCH NEXT FROM curObject INTO @Name, @Owner )rEl{a
END Y` }X5(A@
close curObject ,I"T9k-^
deallocate curObject !!\}-r^y%
GO @}y.
10、SQL SERVER中直接循环写入数据 @c^ Dl
declare @i int (dlp5:lQz
set @i=1 88HqP!m%P:
while @i<30 W&5/1``u\
begin
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insert into test (userid) values(@i) m%0-3c(
set @i=@i+1 '0Cp
end GDSV:]hL
小记存储过程中经常用到的本周,本月,本年函数 }=X: F1S
Dateadd(wk,datediff(wk,0,getdate()),-1) o`f^ m
Dateadd(wk,datediff(wk,0,getdate()),6) $w(RJ/
Dateadd(mm,datediff(mm,0,getdate()),0) ?R]`M_^&u!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 9a*#r;R
Dateadd(yy,datediff(yy,0,getdate()),0) tV!?Ol
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) t:2DB)
上面的SQL代码只是一个时间段 "Z&.m..gc
Dateadd(wk,datediff(wk,0,getdate()),-1) v,i|:;G
Dateadd(wk,datediff(wk,0,getdate()),6) "t^v;?4
就是表示本周时间段. W>#yXg9
下面的SQL的条件部分,就是查询时间段在本周范围内的: prZ
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) g}MUfl-L
而在存储过程中 +2`BZ}5y
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) PC9,;T&7_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~| j
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