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。 nCV7(ldmH
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一、基础 wtL=^
1、说明:创建数据库 owa&HW/_
CREATE DATABASE database-name g9Dynm5
2、说明:删除数据库 1e9~):C~W
drop database dbname (3K,f4S@
3、说明:备份sql server sc-+?i
--- 创建 备份数据的 device #3>jgluM'
USE master modem6#x'
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' *k&V;?x|wt
--- 开始 备份 U$@}!X
BACKUP DATABASE pubs TO testBack 3 %BI+1&T_
4、说明:创建新表 %IIFLlD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )C\/ (
根据已有的表创建新表: g^:`h
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A:create table tab_new like tab_old (使用旧表创建新表) ifWQwS/,a
B:create table tab_new as select col1,col2... from tab_old definition only -oZw+ge}
5、说明:删除新表 $qpW?<>,0
drop table tabname hBz>E 4mEv
6、说明:增加一个列 CZ^
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Alter table tabname add column col type `uDOIl
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 @}r
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7、说明:添加主键: Alter table tabname add primary key(col) h0x'QiCc
说明:删除主键: Alter table tabname drop primary key(col) 1TzwXX7
8、说明:创建索引:create [unique] index idxname on tabname(col....) KAVkYL0
删除索引:drop index idxname Vv`94aQTD
注:索引是不可更改的,想更改必须删除重新建。 6c>:h)?
9、说明:创建视图:create view viewname as select statement bO('y@)X
删除视图:drop view viewname ~USyN'5lU7
10、说明:几个简单的基本的sql语句 S%?%06$
选择:select * from table1 where 范围 W}k/>V_
插入:insert into table1(field1,field2) values(value1,value2) 1JOoICjB
删除:delete from table1 where 范围 !u:;Ew
更新:update table1 set field1=value1 where 范围 `PLax@]2
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! C%%gCPI^y
排序:select * from table1 order by field1,field2 [desc] i}f" 'KW
总数:select count as totalcount from table1 3C;;z
求和:select sum(field1) as sumvalue from table1 `Um-Y'KE
平均:select avg(field1) as avgvalue from table1 7uu\R=$
最大:select max(field1) as maxvalue from table1 cl{mRt0
最小:select min(field1) as minvalue from table1 Q4L7{^[X
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11、说明:几个高级查询运算词 SpIiMu(
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A: UNION 运算符 q&:%/?)x
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。 ,t*H: *
B: EXCEPT 运算符 y\9#"=+
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&ff1(j(
C: INTERSECT 运算符 (6
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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。 @bAuR
注:使用运算词的几个查询结果行必须是一致的。 e?o/H
12、说明:使用外连接 0\k{v
A、left outer join: +T,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。 tp"eXA0n
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
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B:right outer join: so Lmr's
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。 ?5%o-hB|
C:full outer join: x lsAct:
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。 F{
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二、提升 iJKGzHvS
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Nn?$}g
法一:select * into b from a where 1<>1 yKz%-6cpSl
法二:select top 0 * into b from a rzvKvGd#N
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) /z}b1m+
insert into b(a, b, c) select d,e,f from b; 4`o<e)c3
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Le/}xST@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \lwLVe
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. D'% O<.m
4、说明:子查询(表名1:a 表名2:b) 0xeY0!ux
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) "kVzN22
5、说明:显示文章、提交人和最后回复时间 |v1*
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ,.|/B^jV
6、说明:外连接查询(表名1:a 表名2:b) R`Hy0;X
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :FmH=pI!=
7、说明:在线视图查询(表名1:a ) 6 =G=4{q
select * from (SELECT a,b,c FROM a) T where t.a > 1; Z@>kqJ%
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 I_R 6
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select * from table1 where time between time1 and time2 5-&"nn2*}1
select a,b,c, from table1 where a not between 数值1 and 数值2 ##alzC
9、说明:in 的使用方法 Cm"S=gV
select * from table1 where a [not] in ('值1','值2','值4','值6') =u.23#.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 D O||o&u
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) VZ
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11、说明:四表联查问题: `'pAiu
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... -]n%+,3L
12、说明:日程安排提前五分钟提醒 zXbA$c
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 AYp~;@
13、说明:一条sql 语句搞定数据库分页 bUYjmb2g)
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 vWa\8y f
14、说明:前10条记录 BP\6N%HC%&
select top 10 * form table1 where 范围 U9
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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.) 9}4~3_gv;M
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) vF[ 4kDHk
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 dB:c2
(select a from tableA ) except (select a from tableB) except (select a from tableC) cz|?j
17、说明:随机取出10条数据 {9^p3Q+:P
select top 10 * from tablename order by newid() k;qWiYMV
18、说明:随机选择记录 -YrMVoZl
select newid() Ea-U+7JC
19、说明:删除重复记录 9^nRwo
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) t-<BRnxhE
20、说明:列出数据库里所有的表名 H(y Gh
select name from sysobjects where type='U' K5jeazasp
21、说明:列出表里的所有的 +F2X2e)g"
select name from syscolumns where id=object_id('TableName') #5{BxX&\
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。 L1y71+iqU
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 K{B|
显示结果: ovDPnf(
type vender pcs G!h75G20
电脑 A 1 :AI%{EV-L
电脑 A 1 ZNL+w4
光盘 B 2 (Fq:G) $
光盘 A 2 pUW7p
手机 B 3 3=*ur( Qy
手机 C 3 Z/|=@gpw
23、说明:初始化表table1 Tf?`_jL
TRUNCATE TABLE table1 -8<vW e
24、说明:选择从10到15的记录 :fq4oHA#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Zs ,6}m\
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三、技巧 KD H<T4#x
1、1=1,1=2的使用,在SQL语句组合时用的较多 kQQDaZ8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, g#cet{>
如: LhM$!o?W
if @strWhere !='' *;~u 5y2b
begin gU NWM^n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BBv+*jj
end )S/=5Uc
else 8F@Sy,D
begin DH.UJ+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Kpa$1x
end X8N9*vy
我们可以直接写成 5sN6&'[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6]kBG?m0
2、收缩数据库 N^@:+,<3
--重建索引 P8ZmrtQm
DBCC REINDEX 6 . )Xeb"
DBCC INDEXDEFRAG _{gqi$Mi
--收缩数据和日志 {IaDZ/XS6
DBCC SHRINKDB 5Z5x\CcC3
DBCC SHRINKFILE M}f(-,9
3、压缩数据库 cC NRv$IO\
dbcc shrinkdatabase(dbname) D|Wlq~IpQ
4、转移数据库给新用户以已存在用户权限 22U`1AD3U
exec sp_change_users_login 'update_one','newname','oldname' +oq<}CNr{
go Im@OAR4,R
5、检查备份集 0Oc?:R'$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b78~{ht`
6、修复数据库 8N?D1;F;
ALTER DATABASE [dvbbs] SET SINGLE_USER KB(W'M_D\
GO %Ta"H3ZW
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o[iN/
GO ( N};.DB1Y
ALTER DATABASE [dvbbs] SET MULTI_USER vv{+p(~**O
GO +@?'dw
7、日志清除 v+W'0ymbnV
SET NOCOUNT ON f.+1Ubq!5
DECLARE @LogicalFileName sysname, |5O>7~Tp
@MaxMinutes INT, f5FEHyj|
@NewSize INT .g\Oj0Cbxh
USE tablename -- 要操作的数据库名 D&D6!jz
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 0<NS1y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. a.}#nSYP
@NewSize = 1 -- 你想设定的日志文件的大小(M) L\E>5G;
-- Setup / initialize 6=;(~k&x9:
DECLARE @OriginalSize int EG\;l9T
SELECT @OriginalSize = size ZH9Fs'c=
FROM sysfiles =DDKGy.g
WHERE name = @LogicalFileName jy?*` q1]
SELECT 'Original Size of ' + db_name() + ' LOG is ' + =CZRX'
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \AKP ea=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \y]K]iv
FROM sysfiles ^jwzCo-
WHERE name = @LogicalFileName J:Qx5;b;
CREATE TABLE DummyTrans z[v4(pO6
(DummyColumn char (8000) not null) VN!nef
DECLARE @Counter INT, X.k8w\~
@StartTime DATETIME, >(S)aug$1
@TruncLog VARCHAR(255) 10*Tk 8
SELECT @StartTime = GETDATE(), x5BS|3W$a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) jYRSV7d
EXEC (@TruncLog) %HoD)OJe
-- Wrap the log if necessary. e'G=.:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =2Yt[8';
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1ruI++P
AND (@OriginalSize * 8 /1024) > @NewSize ]Z8u0YtM)
BEGIN -- Outer loop. /}8Au$nA
SELECT @Counter = 0 Pd"c*n&9
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) e8^/S^ =&d
BEGIN -- update Af]zv~uM
INSERT DummyTrans VALUES ('Fill Log') 4=Ru{ewRV
DELETE DummyTrans fI<LxU_n:
SELECT @Counter = @Counter + 1 YYYF a
END aH'fAX0bF
EXEC (@TruncLog) RBn/7
END |<,qnf| -
SELECT 'Final Size of ' + db_name() + ' LOG is ' + vjx'yh|
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + jc
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' M?"4{
FROM sysfiles &AJkYh
WHERE name = @LogicalFileName j;]I
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DROP TABLE DummyTrans "I/05k K
SET NOCOUNT OFF !6=;dX
8、说明:更改某个表 x,25ROaHY
exec sp_changeobjectowner 'tablename','dbo' iIX%%r+
9、存储更改全部表 bXF8V
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Kgr<OL}V J
@OldOwner as NVARCHAR(128), @i>)x*I#AI
@NewOwner as NVARCHAR(128) ?96r7C|
AS I!*P' {lh
DECLARE @Name as NVARCHAR(128) 92<+ug =
DECLARE @Owner as NVARCHAR(128) `+n#CWZ"Y
DECLARE @OwnerName as NVARCHAR(128) C78g|n{
DECLARE curObject CURSOR FOR E0+L?(;
select 'Name' = name, *eIX"&ba
'Owner' = user_name(uid) xB Wl|j
from sysobjects %QEBY>|lI
where user_name(uid)=@OldOwner g]?pY
order by name $`3yImv+w
OPEN curObject O|8@cO
FETCH NEXT FROM curObject INTO @Name, @Owner }vZf&ib-
WHILE(@@FETCH_STATUS=0) -^m?%_<50l
BEGIN |w|c!;,
if @Owner=@OldOwner it\$Pih]
begin 2{b/*w
set @OwnerName = @OldOwner + '.' + rtrim(@Name) M^:JhX{
exec sp_changeobjectowner @OwnerName, @NewOwner >=; -:
end ojnO69v
-- select @name,@NewOwner,@OldOwner L.'61ZU
FETCH NEXT FROM curObject INTO @Name, @Owner \{ EVRRXn
END oqF?9<Vgc,
close curObject &!X<F,
deallocate curObject TF:'6#p
GO Gkuqe3
10、SQL SERVER中直接循环写入数据 >o1dc*
declare @i int u.X]K:Yow
set @i=1 Hvk~BP'
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while @i<30 1cOR?=G~
begin ,M3hE/rb/
insert into test (userid) values(@i) (dSYb&]
set @i=@i+1 Ct)58f2
end ({t^/b*8
小记存储过程中经常用到的本周,本月,本年函数 }[JB%
Dateadd(wk,datediff(wk,0,getdate()),-1) 5`p9Xo>)yW
Dateadd(wk,datediff(wk,0,getdate()),6) i-v: %
Dateadd(mm,datediff(mm,0,getdate()),0) xcW\U^1d
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) K{DC{yLu
Dateadd(yy,datediff(yy,0,getdate()),0) 0"OEOYs}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) wkZwtq
上面的SQL代码只是一个时间段 0QZT<Zs
Dateadd(wk,datediff(wk,0,getdate()),-1) 88_ef7w
Dateadd(wk,datediff(wk,0,getdate()),6) )^o.H~Pv
就是表示本周时间段. ,.9 lz
下面的SQL的条件部分,就是查询时间段在本周范围内的: Uyb0iQ-,s
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) `qs,V
而在存储过程中 qF~9:`
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 7o+L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) B3ItZojAuw