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。 [p^N].K$
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一、基础 r BQFC4L
1、说明:创建数据库 $hZb<Xz
CREATE DATABASE database-name sEP-jEuwG
2、说明:删除数据库 fl #gWAM
drop database dbname (Z;;v|F.i=
3、说明:备份sql server qpjtF'
--- 创建 备份数据的 device r9McCebIW
USE master :8\!; !
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ,K'>s<}
--- 开始 备份 VJmX@zX9
BACKUP DATABASE pubs TO testBack >77N5>]e
4、说明:创建新表 xOnbYU
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |WqEJ*$,
根据已有的表创建新表: r2M Iw
A:create table tab_new like tab_old (使用旧表创建新表) V3DXoRE-8i
B:create table tab_new as select col1,col2... from tab_old definition only
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5、说明:删除新表 D/uGL
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drop table tabname F67%xz0
6、说明:增加一个列 ()a(PvEO
Alter table tabname add column col type G5a PjP
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。 (ZH5/VKp
7、说明:添加主键: Alter table tabname add primary key(col) |:BKexjHL
说明:删除主键: Alter table tabname drop primary key(col) 5#3/
8、说明:创建索引:create [unique] index idxname on tabname(col....) ARvT
删除索引:drop index idxname ;T0F1
注:索引是不可更改的,想更改必须删除重新建。 $fES06%
9、说明:创建视图:create view viewname as select statement F9@,T8I
删除视图:drop view viewname 3C'`K,
10、说明:几个简单的基本的sql语句 A(zF[\{]
选择:select * from table1 where 范围 u>SGa @R)
插入:insert into table1(field1,field2) values(value1,value2) exT
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删除:delete from table1 where 范围 uTTM%-DMHT
更新:update table1 set field1=value1 where 范围 })RT2zw}
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1henQiIO
排序:select * from table1 order by field1,field2 [desc] B7BXS*_b
总数:select count as totalcount from table1 z ea=vx>`
求和:select sum(field1) as sumvalue from table1 v'gP,UO-%D
平均:select avg(field1) as avgvalue from table1 [!1z;
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最大:select max(field1) as maxvalue from table1 \i_y(;
最小:select min(field1) as minvalue from table1 GG%X1c8K
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11、说明:几个高级查询运算词 tVVnQX
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A: UNION 运算符 AKs=2N>7
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 C$Pe<C#
B: EXCEPT 运算符 2ED^uc:
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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。 gSLwpIK%
C: INTERSECT 运算符 5dOA^P@`,M
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。 hpp>+=
注:使用运算词的几个查询结果行必须是一致的。 Xb +)@Y4h
12、说明:使用外连接 b[p<kMTir
A、left outer join: ;ELQIHnD"
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。 {T|sU\| Q
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 ZfalB
B:right outer join: U U!M/QJ
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。 Cx$C+
C:full outer join: v\7k
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。 s33< }O0
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二、提升 .Rl58]x~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !#cZ!
法一:select * into b from a where 1<>1 8was/^9;
法二:select top 0 * into b from a 5"(AqXoq
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) t95hI DtD
insert into b(a, b, c) select d,e,f from b; clfi)-^{K
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) *4}lV8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 S~^0
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &X0/7)*"v
4、说明:子查询(表名1:a 表名2:b) Ij;=
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) V"":_`1VW
5、说明:显示文章、提交人和最后回复时间 V#
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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 LX A1rgUWT
6、说明:外连接查询(表名1:a 表名2:b) yH_L<n
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!" ]e*q
7、说明:在线视图查询(表名1:a ) :()(P9?
select * from (SELECT a,b,c FROM a) T where t.a > 1; pcw!e_"+
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 mw}obblR
select * from table1 where time between time1 and time2 JHpoW}7QB
select a,b,c, from table1 where a not between 数值1 and 数值2 )US|&>
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9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') 0_JbE
10、说明:两张关联表,删除主表中已经在副表中没有的信息 'TclH80
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }G
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11、说明:四表联查问题: AU1P?lk
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 ..... L8-
12、说明:日程安排提前五分钟提醒 _nu
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N!6{c~^
13、说明:一条sql 语句搞定数据库分页 pAg;Rib
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 *0bbSw1kc
14、说明:前10条记录 "aNl2 T
select top 10 * form table1 where 范围 `K[:<p}
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.) 7Cf%v`B4D
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) FI@2KM
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 ^9T6Ix{=
(select a from tableA ) except (select a from tableB) except (select a from tableC) EFeG[bxM
17、说明:随机取出10条数据 !NuYx9L?L
select top 10 * from tablename order by newid() it!i'lG
18、说明:随机选择记录 !fdni}f)
select newid() {#M=gDhbX
19、说明:删除重复记录 qmUq9bV
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 9_IR%bm
20、说明:列出数据库里所有的表名 }D.?O,ue
select name from sysobjects where type='U' ?#]K54?
21、说明:列出表里的所有的 wP3PI.g-g
select name from syscolumns where id=object_id('TableName') @~6A9Fr
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。 5xW)nEV
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 N>i1TM2
显示结果: ]*a)'k_@[
type vender pcs sQW$P9s
c
电脑 A 1 .K^'Q|?
电脑 A 1 @ [_I|
光盘 B 2 ]7kq@o/7
光盘 A 2 ;cZ9C 1
手机 B 3 jeb<qi>
手机 C 3 #r 1
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23、说明:初始化表table1 z79L2lJn
TRUNCATE TABLE table1 :6LOb f\01
24、说明:选择从10到15的记录 cqeId&Cg
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G-oCA1UdN
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三、技巧 9m56oT'U{
1、1=1,1=2的使用,在SQL语句组合时用的较多 K/oPfD]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 'T[=Uuj"
如: :j$K.3n
if @strWhere !='' !7J;h{3Uw
begin l ,)l"6OV
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #m
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end "d'xT/l
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else yZI4%fen
begin G1B~?i2$ ?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' G~)jk+Qq
end 'ntb.S)
我们可以直接写成 *sf9(%j
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ] d| -r:4
2、收缩数据库 :YjOv
--重建索引 "Ks%!
DBCC REINDEX !Dkz6B*
DBCC INDEXDEFRAG Q"8)'dL'
--收缩数据和日志 7d/wT+f
DBCC SHRINKDB n);2b\&
DBCC SHRINKFILE # l~d
3、压缩数据库 XRs/gUT
dbcc shrinkdatabase(dbname) [K13Jy+
4、转移数据库给新用户以已存在用户权限 O89<IXk
exec sp_change_users_login 'update_one','newname','oldname' g2C-)*'{yh
go `ZN@L<I6
5、检查备份集 H_;Dq*
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ` 2|~Z
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6、修复数据库 hX)r%v:
ALTER DATABASE [dvbbs] SET SINGLE_USER -a3+C,I8g
GO fh$U"
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /@FB;`'
GO 5`oor86
ALTER DATABASE [dvbbs] SET MULTI_USER k}>l+_*+7
GO 05*_h0}
7、日志清除 vJGxD\h
SET NOCOUNT ON v Xio1hu
DECLARE @LogicalFileName sysname, z1!ya#,$
@MaxMinutes INT, m|~,# d@
@NewSize INT SrK;b .
USE tablename -- 要操作的数据库名 doc5;?6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 fFXs:(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. DWJ%r"aN
@NewSize = 1 -- 你想设定的日志文件的大小(M) $qQ6u!
-- Setup / initialize g^)> -$=
DECLARE @OriginalSize int <!X'- >i%q
SELECT @OriginalSize = size HAo8]?J
FROM sysfiles ] >ipC,v
WHERE name = @LogicalFileName Djf2ir'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + toTAWT D
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /dOQ4VA\
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' pRc(>P3;
FROM sysfiles WbH/K]/1)h
WHERE name = @LogicalFileName !::k\}DS
CREATE TABLE DummyTrans IvIBf2D;Q
(DummyColumn char (8000) not null) NL&g/4A[a
DECLARE @Counter INT, &%u,b~cL?
@StartTime DATETIME, |BH,
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@TruncLog VARCHAR(255) k`)LO`))
SELECT @StartTime = GETDATE(), C==tJog[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3Un/-4uL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Z+t?ah00
EXEC (@TruncLog) c'`7p/l.
-- Wrap the log if necessary. /UyW&]nK
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w0/W=!_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l$m^{6IYc
AND (@OriginalSize * 8 /1024) > @NewSize Zy*}C,Z
BEGIN -- Outer loop. 3{M IBMA
SELECT @Counter = 0 w#PaN83+
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) oE)c8rE
BEGIN -- update oK5(,8
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INSERT DummyTrans VALUES ('Fill Log') -<z'f){gb
DELETE DummyTrans " "a+Nc
SELECT @Counter = @Counter + 1 D{BH~IM
END :Yz.Bfli
EXEC (@TruncLog) }T,E$vsx
END p6=#LwL'
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Arp4$h
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + R<UjhCvx.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' aE{b65'Dt
FROM sysfiles _%zU^aE
WHERE name = @LogicalFileName W]Ph:O^5c
DROP TABLE DummyTrans 6\0GVM\
SET NOCOUNT OFF {##A|{$3%
8、说明:更改某个表 * y(2BrL>
exec sp_changeobjectowner 'tablename','dbo' T82=R@7
9、存储更改全部表 SmR*b2U
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch dje3&a
@OldOwner as NVARCHAR(128), ) 0}o bPp
@NewOwner as NVARCHAR(128) {7/6~\'/@
AS `}Q;2 F
DECLARE @Name as NVARCHAR(128) MeplM$9
DECLARE @Owner as NVARCHAR(128) {{EQM
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DECLARE @OwnerName as NVARCHAR(128) q6_1`Ew
DECLARE curObject CURSOR FOR gu:..'V
select 'Name' = name, ;'o>6I7Ph
'Owner' = user_name(uid) ?J6hiQvL
from sysobjects qA30z%#z_
where user_name(uid)=@OldOwner sL/Lw
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order by name \17)=W
OPEN curObject n.1a1 Tf
FETCH NEXT FROM curObject INTO @Name, @Owner P{>T?-Hj
WHILE(@@FETCH_STATUS=0) ?q,x?`|(8
BEGIN ;=^WIC+Nr
if @Owner=@OldOwner 0e7v ?UT
begin q0c)pxD%`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) i;dr(c/ft
exec sp_changeobjectowner @OwnerName, @NewOwner ,MvvW{EY
end MPL2#YU/a
-- select @name,@NewOwner,@OldOwner 1}ToR=
FETCH NEXT FROM curObject INTO @Name, @Owner \'p7,F{:>5
END W}=2?vHV=
close curObject ]iNSa{G
deallocate curObject v#/,,)m
GO lJYv2EZ
10、SQL SERVER中直接循环写入数据 \uPT-M*
declare @i int 6|jE3rHw
set @i=1 Ppp&3h[dW)
while @i<30 &Y#9~$V=
begin QiRzA4-zq
insert into test (userid) values(@i) 9QX{b+}"e
set @i=@i+1 D3HB`{
end 3=K-+dhk|t
小记存储过程中经常用到的本周,本月,本年函数 Ys3C'Gc
Dateadd(wk,datediff(wk,0,getdate()),-1) 7olA@;$
Dateadd(wk,datediff(wk,0,getdate()),6) DHJnz>bE
Dateadd(mm,datediff(mm,0,getdate()),0) 4PF4#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4@W.{|2~
Dateadd(yy,datediff(yy,0,getdate()),0) zYs? w=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) (f.A5~e
上面的SQL代码只是一个时间段 ?t%5 /
Dateadd(wk,datediff(wk,0,getdate()),-1) <