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。 R@u6mMX{N,
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一、基础 Xq1n1_Z
1、说明:创建数据库 vH9/}w2
CREATE DATABASE database-name wqK>=Ri_
2、说明:删除数据库 [-=PK\ B
drop database dbname `fj(xrI
3、说明:备份sql server iO(9#rV
--- 创建 备份数据的 device Atzp\oO
USE master JIQS'r
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' FD,M.kbg
--- 开始 备份 /k l0(='
BACKUP DATABASE pubs TO testBack zsc8Lw
4、说明:创建新表 \|L@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5JBenTt
根据已有的表创建新表: )W(?wv!,
A:create table tab_new like tab_old (使用旧表创建新表) 1)X%n)2pr
B:create table tab_new as select col1,col2... from tab_old definition only P
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5、说明:删除新表 `[2nxP>w`
drop table tabname 1.]#FJe
6、说明:增加一个列 R4%!W~K
Alter table tabname add column col type &1{RuV&t
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。 4hr;k0sD
7、说明:添加主键: Alter table tabname add primary key(col) #swzZyM$
说明:删除主键: Alter table tabname drop primary key(col) :OUNZDL
8、说明:创建索引:create [unique] index idxname on tabname(col....) .TSj8,
删除索引:drop index idxname n'U*8ID
注:索引是不可更改的,想更改必须删除重新建。 HJ:s)As
9、说明:创建视图:create view viewname as select statement HBXp#$dPc
删除视图:drop view viewname _A;jtS)SY
10、说明:几个简单的基本的sql语句 l%oie1g l
选择:select * from table1 where 范围 r*OSEzGUz
插入:insert into table1(field1,field2) values(value1,value2) y9?B vPp+
删除:delete from table1 where 范围 o5-oQ_j
更新:update table1 set field1=value1 where 范围 7AX<>^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /xWkP{
排序:select * from table1 order by field1,field2 [desc] jxm.x[1ki^
总数:select count as totalcount from table1 g~S>_~WL
求和:select sum(field1) as sumvalue from table1 eo24I0`N
平均:select avg(field1) as avgvalue from table1 a]Bm0gdrO
最大:select max(field1) as maxvalue from table1 9N:Bu'j&/
最小:select min(field1) as minvalue from table1 XTUxMdN
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11、说明:几个高级查询运算词 O$V
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A: UNION 运算符 'p80X^g
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。 7%c9 nY
B: EXCEPT 运算符 \f}S Hh
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。 &HNJ'
C: INTERSECT 运算符 wWKC.N
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。 ><mZOTn e;
注:使用运算词的几个查询结果行必须是一致的。 TxoMCN?7c
12、说明:使用外连接 be |k"s|6)
A、left outer join: nw+L _b
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。 $6Lgaz
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |CexP^;!U
B:right outer join: 47ppyh6@
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 hWfJh0I
C:full outer join: rW0# 6
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 . p^='Kz?
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二、提升 v7&e,:r2E@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) W/<]mm~95
法一:select * into b from a where 1<>1 w}c1zpa
法二:select top 0 * into b from a -v'7;L0K
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B;r U
insert into b(a, b, c) select d,e,f from b; vvU;55-
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) r :{2}nE
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ClCb.Ozj4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ID
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4、说明:子查询(表名1:a 表名2:b) r /63
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) mT
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5、说明:显示文章、提交人和最后回复时间 YAv-5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b E{[c8l2B
6、说明:外连接查询(表名1:a 表名2:b) 22"M#:r$
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 ?_YdVZ
7、说明:在线视图查询(表名1:a ) ^o+2:G5z}
select * from (SELECT a,b,c FROM a) T where t.a > 1; zm-j FY ?
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 0(VH8@h`O
select * from table1 where time between time1 and time2 |\TOSaZ
select a,b,c, from table1 where a not between 数值1 and 数值2 A,ttn5Sh?
9、说明:in 的使用方法 ^0_ *AwIcN
select * from table1 where a [not] in ('值1','值2','值4','值6') bg[k8*.:F
10、说明:两张关联表,删除主表中已经在副表中没有的信息 MC D]n
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =;-/( C
11、说明:四表联查问题: `re]Q0IO
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 ..... d8`^;T
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12、说明:日程安排提前五分钟提醒 [cwc}f^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Oh9wBV
13、说明:一条sql 语句搞定数据库分页 V@&zn8?
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 XaW@CW
14、说明:前10条记录 ~O;!y%
select top 10 * form table1 where 范围 ;{
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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.) QU|{(c
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) R"Nvnpm
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 S5*wUd*p#
(select a from tableA ) except (select a from tableB) except (select a from tableC) PX65Z|~>_
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() "aHY]E{
18、说明:随机选择记录 nud,ag
select newid() )tl=tH/$
19、说明:删除重复记录 */sVuD^b`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) yw^t6E
20、说明:列出数据库里所有的表名 _v{,vLH
select name from sysobjects where type='U' =K I4
21、说明:列出表里的所有的 RXh0hD
select name from syscolumns where id=object_id('TableName') k!H;(B"s-
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。 /6B!&b2f
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 fQi7e5
显示结果: $IX>o&S@|
type vender pcs $9Hod-Z1
电脑 A 1 .\= GfF'
电脑 A 1 t_6sDr'.
光盘 B 2 5Al59]
光盘 A 2 O6LZ<}oUR
手机 B 3 ;ob-'
手机 C 3 7Oe |:Z
23、说明:初始化表table1 w~y+Pv@
TRUNCATE TABLE table1 ]|18tVXc
24、说明:选择从10到15的记录 zDeh#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc :BKY#uH~
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三、技巧 ;Xg6'yxJ
1、1=1,1=2的使用,在SQL语句组合时用的较多 ks<gSCB
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Idop!b5!
如: kD
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if @strWhere !='' .\M@oF
begin 7D\#1h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `=Pn{JaD
end "(5A5>
else xfCq;?MupW
begin FKY|xG9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' u4bPj2N8I
end (2(I|O#
我们可以直接写成 ]Cnj=\'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9-[g/qrF
2、收缩数据库 XmXp0b7
--重建索引 ,u^i0uOg
DBCC REINDEX !31v@v:)
DBCC INDEXDEFRAG RKFj6u
--收缩数据和日志 7\@[e, ^9
DBCC SHRINKDB I$xfCu
DBCC SHRINKFILE v/=O:SM}
3、压缩数据库 G 5w:
dbcc shrinkdatabase(dbname) QE[ETv
4、转移数据库给新用户以已存在用户权限 mwVH>3{j
exec sp_change_users_login 'update_one','newname','oldname' | V Ps5
go >i7zV`eK
5、检查备份集 ]S9~2;2^,
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <^6|ZgR
6、修复数据库 L3iYZ>]
ALTER DATABASE [dvbbs] SET SINGLE_USER "^VKs_U8o
GO %myg67u
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x9XQ
GO z1wy@1o'
ALTER DATABASE [dvbbs] SET MULTI_USER 3$[!BPLFO
GO ;V`e%9.
7、日志清除 Q!(16
SET NOCOUNT ON tNg}:a|J
DECLARE @LogicalFileName sysname, ]u
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@MaxMinutes INT, [R*UPa
@NewSize INT -8;U1 ^#
USE tablename -- 要操作的数据库名 #]<j.Fc`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ic/D!J{Y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d]6.$"\"p
@NewSize = 1 -- 你想设定的日志文件的大小(M) &l2oyQEF)
-- Setup / initialize }md[hi J
DECLARE @OriginalSize int \E1[ /
SELECT @OriginalSize = size 7y.$'<
FROM sysfiles ce!0Ws+
WHERE name = @LogicalFileName -:b0fKn
SELECT 'Original Size of ' + db_name() + ' LOG is ' + H(9%SP@[c
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + GhpVi<FL
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' wR
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FROM sysfiles ' _Ij9{M
WHERE name = @LogicalFileName ukb2[mb*u
CREATE TABLE DummyTrans TbbtD"b?
(DummyColumn char (8000) not null) Cfqgu;m
DECLARE @Counter INT, XcB!9AIO
@StartTime DATETIME, I!3qb-.Q
@TruncLog VARCHAR(255) #8iRWm0*6
SELECT @StartTime = GETDATE(), "4"gHs
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' T(zERWo
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ]8FSs/4
EXEC (@TruncLog) b!Pz~faXD
-- Wrap the log if necessary. C"no>A^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired udVEOn$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |n3fAN
AND (@OriginalSize * 8 /1024) > @NewSize oe`t ? (U
BEGIN -- Outer loop. 2iC7c6hc
SELECT @Counter = 0 k44sV.G4L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) L;$Gn"7~
BEGIN -- update xR
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INSERT DummyTrans VALUES ('Fill Log') $}RBK'cr}
DELETE DummyTrans gBb+Q,
SELECT @Counter = @Counter + 1 3*C9;Q}
END ,paD/
EXEC (@TruncLog) L]I ;{Y
END !j[Oyr|
SELECT 'Final Size of ' + db_name() + ' LOG is ' + h}r64<Y2{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?4v&TB@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,?g}->ZB
FROM sysfiles HLm6BtE
WHERE name = @LogicalFileName N9 @@n:JT
DROP TABLE DummyTrans uLXMEx<^
SET NOCOUNT OFF 6cH.s+
8、说明:更改某个表 #AHX{<
exec sp_changeobjectowner 'tablename','dbo' &?C%
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9、存储更改全部表 s<,[xkMB
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch H:byCFN-
@OldOwner as NVARCHAR(128), tmEF7e`(o
@NewOwner as NVARCHAR(128) &U/7D!^X
AS F;$z[z
DECLARE @Name as NVARCHAR(128) 7 -yf
DECLARE @Owner as NVARCHAR(128) j"o8]UT/
DECLARE @OwnerName as NVARCHAR(128) s8;/'?K
DECLARE curObject CURSOR FOR t;X
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select 'Name' = name, [yj-4v%u`
'Owner' = user_name(uid) gI<e=|J6w
from sysobjects -DD2
where user_name(uid)=@OldOwner WgX9k J
order by name kU^*hd]
OPEN curObject W2cgxT
FETCH NEXT FROM curObject INTO @Name, @Owner ?/"Fwjau
WHILE(@@FETCH_STATUS=0) _Bh-*e2k
BEGIN _"Yi>.{]
if @Owner=@OldOwner +Y;/10p
begin &L6xagR7M
set @OwnerName = @OldOwner + '.' + rtrim(@Name) FVw;`{
exec sp_changeobjectowner @OwnerName, @NewOwner g2Pa-}{
end ~nO]R
-- select @name,@NewOwner,@OldOwner %6Wv-:LY
FETCH NEXT FROM curObject INTO @Name, @Owner <j
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END <NRW^#g<x
close curObject P X/{
deallocate curObject 'MZX"t
GO ?Pg{nlJvq
10、SQL SERVER中直接循环写入数据 d +0(H
declare @i int _Q&O#f
set @i=1 T^FeahA7;
while @i<30 peW4J<,
begin Si=zxy T
insert into test (userid) values(@i) qy@v,a
set @i=@i+1 UC&f
end w}2 ;f=
小记存储过程中经常用到的本周,本月,本年函数 4#D=+70'
Dateadd(wk,datediff(wk,0,getdate()),-1) JBzRL"|
Dateadd(wk,datediff(wk,0,getdate()),6) G-FeDP
Dateadd(mm,datediff(mm,0,getdate()),0) 5X"y46i,H
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ErZYPl
Dateadd(yy,datediff(yy,0,getdate()),0) `s[77V>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) m"3gTqG
上面的SQL代码只是一个时间段 iIrH&}2
Dateadd(wk,datediff(wk,0,getdate()),-1) C'5b)0km
Dateadd(wk,datediff(wk,0,getdate()),6) xF|P6GXg
就是表示本周时间段. up`.#GWm
下面的SQL的条件部分,就是查询时间段在本周范围内的:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) jm~(OLg
而在存储过程中 dC&{zNG
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) )0F\[Jl}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) q]PeS~PjF\