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。 .}E@7^X
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一、基础 *@WBaN+
1、说明:创建数据库 =<AG}by![
CREATE DATABASE database-name j!@,r^(
2、说明:删除数据库 `H9!Z$7G
drop database dbname OU*skc>
3、说明:备份sql server 0%yPuY>
--- 创建 备份数据的 device w BoP&l
USE master ~b%dBn]n>
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Oe;1f#`5
--- 开始 备份 Fz5eCe\B
BACKUP DATABASE pubs TO testBack Ci2*5n<
4、说明:创建新表 lbh7`xCR
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) /XdLdA!v
根据已有的表创建新表: &3itBQF
A:create table tab_new like tab_old (使用旧表创建新表) =p dLh
B:create table tab_new as select col1,col2... from tab_old definition only 474
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5、说明:删除新表 1k{H,p7
drop table tabname ?/(*cA
6、说明:增加一个列 *T.V5FB0S
Alter table tabname add column col type =6=l.qyYK
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 hW\'EJ
7、说明:添加主键: Alter table tabname add primary key(col) iEbW[sX[4
说明:删除主键: Alter table tabname drop primary key(col) 7Q~$&G
8、说明:创建索引:create [unique] index idxname on tabname(col....) *9`k$'
删除索引:drop index idxname 3~LNz8Z*
注:索引是不可更改的,想更改必须删除重新建。 G)gb5VW k
9、说明:创建视图:create view viewname as select statement -oY8]HrXfK
删除视图:drop view viewname cmY `$=
10、说明:几个简单的基本的sql语句 )"63g
选择:select * from table1 where 范围 gOp81)
插入:insert into table1(field1,field2) values(value1,value2) t&IWKu#
删除:delete from table1 where 范围 >A}ra ^gU
更新:update table1 set field1=value1 where 范围 (R9"0WeF
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7_eV.'h
排序:select * from table1 order by field1,field2 [desc] {yMkd4v
总数:select count as totalcount from table1 !yz3:Yzu
求和:select sum(field1) as sumvalue from table1 V=Z%y$1Bc
平均:select avg(field1) as avgvalue from table1 iaQFVROu
最大:select max(field1) as maxvalue from table1 Z5`V\$
最小:select min(field1) as minvalue from table1 PH?<)Wj9i
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11、说明:几个高级查询运算词 FR\r/+n:t0
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A: UNION 运算符 :\%hv>}|
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 rY$wC%
B: EXCEPT 运算符 ppeF,Q
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。 V2g"5nYT
C: INTERSECT 运算符 \\Z?v,XsS
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。 }$* z:E
注:使用运算词的几个查询结果行必须是一致的。 Q_*.1L
12、说明:使用外连接 &0{&4,
A、left outer join: BT
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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。 Hdjp^O!
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 \JP9lJ3<
B:right outer join: -tp3qi
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。 T7 (d
C:full outer join: "i!W(}x+
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。 C\ 34R
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二、提升 WWLf'89It
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Wq<HsJd/
法一:select * into b from a where 1<>1 y"H(F,(N
法二:select top 0 * into b from a %-|$7?~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) khQfLA
insert into b(a, b, c) select d,e,f from b; `'pfBVBz
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) eGWwPSIp
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 "M,Hm!j
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 9|K:\!7
4、说明:子查询(表名1:a 表名2:b) f^Q)lIv
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) Q{~;4+ZD
5、说明:显示文章、提交人和最后回复时间 gU?M/i2
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b tnq ZlS
6、说明:外连接查询(表名1:a 表名2:b) #=Whh
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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;LP#(h ?
7、说明:在线视图查询(表名1:a ) .EjjCE/v-
select * from (SELECT a,b,c FROM a) T where t.a > 1; <B+
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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 ;U? 323Z
select * from table1 where time between time1 and time2 rgEN~e'
select a,b,c, from table1 where a not between 数值1 and 数值2 -JclEp
9、说明:in 的使用方法 )?(_vrc<
select * from table1 where a [not] in ('值1','值2','值4','值6') SN$3cg]z
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Q0L1!}w
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) R,-DP/ (im
11、说明:四表联查问题: <4I`|D3@
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 ..... E:P_CDSd]
12、说明:日程安排提前五分钟提醒 "a<:fEsSE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 C~M,N|m+^
13、说明:一条sql 语句搞定数据库分页 qI[AsM+
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 Io('kCOR;
14、说明:前10条记录 unr`.}A2>
select top 10 * form table1 where 范围 mlz|KI~\F;
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.) HrRw
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) V\AF%=6}
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 'Xasd3*Py
(select a from tableA ) except (select a from tableB) except (select a from tableC) -8SZ}J
17、说明:随机取出10条数据 l?HC-_Pbh
select top 10 * from tablename order by newid() u!McPM8Yk
18、说明:随机选择记录 <JW%h :\t
select newid() 7&Ie3[Rm_3
19、说明:删除重复记录 V@`%k]k
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) |#B)`r8
20、说明:列出数据库里所有的表名 $7p0<<Nck
select name from sysobjects where type='U' {k']nI.>
21、说明:列出表里的所有的 (Y"./BDY
select name from syscolumns where id=object_id('TableName') p<B*)1Tj0
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 D% 2S!
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type B!J&=*=e
显示结果: _V3}F1?W
type vender pcs [6nN]U~ Y
电脑 A 1 \WZSY||C|_
电脑 A 1 &B$%|~Y5
光盘 B 2 d 0:;IUG
光盘 A 2 sDkO!P
手机 B 3 TR:4$92:H
手机 C 3 WKq{g+a
23、说明:初始化表table1 -I~\
TRUNCATE TABLE table1 `L3{y/U'
24、说明:选择从10到15的记录 \{o<-S;h
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 1Q$/L+uJ5
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三、技巧 {G=|fgz
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?%b#FXA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +rKV*XX@
如: Pe@*')o*
if @strWhere !='' >{"E~U
begin = @lM*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Uf|@h
end rW*[sLl3
else 2Xv$
begin 6<YAoo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t]ID
end mwF{z.t"
我们可以直接写成 !"
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S]gV! Q4%
2、收缩数据库 <
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--重建索引 ?p>m;Aq
DBCC REINDEX "l B%"}
DBCC INDEXDEFRAG uFfk!
--收缩数据和日志 N \woFrG
DBCC SHRINKDB *^ua2s.
DBCC SHRINKFILE 2
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3、压缩数据库 ixB"6O
dbcc shrinkdatabase(dbname) 'lOpoWDL
4、转移数据库给新用户以已存在用户权限 M|UCV_omN
exec sp_change_users_login 'update_one','newname','oldname' IJLuu@kRm,
go H4W!@"e
5、检查备份集 <#)Q.P
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' g!`^!Q/($
6、修复数据库 sLc,Dx"+
ALTER DATABASE [dvbbs] SET SINGLE_USER N <M6~
GO bDq<]h_7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK xr31<4B
GO WFvVu3
ALTER DATABASE [dvbbs] SET MULTI_USER ".kH5(:
GO W A#y&
7、日志清除 zuJ@@\75
SET NOCOUNT ON Gf-GDy\{
DECLARE @LogicalFileName sysname, H2yPVJ\Y)"
@MaxMinutes INT, 4UMOC_
@NewSize INT z7&m,:M
USE tablename -- 要操作的数据库名 =RHIB1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 l(8@?t^;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Axla@
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9r 5(
-- Setup / initialize <jh=W9.N_
DECLARE @OriginalSize int <9S 5
SELECT @OriginalSize = size ;S'1fci6
FROM sysfiles x}O J~Yk]
WHERE name = @LogicalFileName NOl/y@#
SELECT 'Original Size of ' + db_name() + ' LOG is ' + E=ObfN"ge
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "!:)qVL^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' t V2o9!N4
FROM sysfiles /#[mV(k
WHERE name = @LogicalFileName (Y
CREATE TABLE DummyTrans RAA,%rRhu(
(DummyColumn char (8000) not null) 43*;" w=
DECLARE @Counter INT, UW{C`^?=B
@StartTime DATETIME, -+:t%A?
@TruncLog VARCHAR(255) R=S)O.*R
SELECT @StartTime = GETDATE(), EfX,0Nq T
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' cEK#5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) P9M%B2DQ6f
EXEC (@TruncLog) $]4o!Z
-- Wrap the log if necessary. +9.GNu
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5m?9O7Pg
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Q5*"t*L!N
AND (@OriginalSize * 8 /1024) > @NewSize ">q?(i\
BEGIN -- Outer loop. P&*e\"{
SELECT @Counter = 0 'wo}1^V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) X*`b}^T
BEGIN -- update 6Z;D`X,5
INSERT DummyTrans VALUES ('Fill Log') "||'
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DELETE DummyTrans Rpxg
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SELECT @Counter = @Counter + 1 {#z[iiB
END +a^0Q
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EXEC (@TruncLog) Eg1|Kg\&
END [=>[ 2Ty
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 4H`B]Zt7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + HC|
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' w]US-7
FROM sysfiles Q$Q:Jm53
WHERE name = @LogicalFileName |A2o$H
DROP TABLE DummyTrans .+~9
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SET NOCOUNT OFF ~oRT@E
8、说明:更改某个表 H5be 5
exec sp_changeobjectowner 'tablename','dbo' C-/+n5J
9、存储更改全部表 Sre:l'.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )O>M~
@OldOwner as NVARCHAR(128), Q!h+1fb
@NewOwner as NVARCHAR(128) y)3OQ24
AS b[MKo7
DECLARE @Name as NVARCHAR(128) B8>@q!G8P
DECLARE @Owner as NVARCHAR(128) nE4rB\
DECLARE @OwnerName as NVARCHAR(128) }'h\;8y
DECLARE curObject CURSOR FOR d,o|>e$
select 'Name' = name, Us3zvpy)o
'Owner' = user_name(uid) .~|[*
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from sysobjects Gg%pU+'T
where user_name(uid)=@OldOwner od*#)
order by name >P-'C^:V=
OPEN curObject )ZpMB
FETCH NEXT FROM curObject INTO @Name, @Owner uC2qP)m,^
WHILE(@@FETCH_STATUS=0) DN;$->>
BEGIN 9+~1# |
if @Owner=@OldOwner kE1k@h#/
begin +[pJr-k
set @OwnerName = @OldOwner + '.' + rtrim(@Name) )2R]KU_=g
exec sp_changeobjectowner @OwnerName, @NewOwner srH.$Y;~
end Bd[H@oKru
-- select @name,@NewOwner,@OldOwner ZpZoOdjslV
FETCH NEXT FROM curObject INTO @Name, @Owner 1czU$!MV
END 7Kti&T
close curObject a)!R4
deallocate curObject *]ME]2qP
GO 8x9;3{R
10、SQL SERVER中直接循环写入数据 #y1M1O g
declare @i int Jjh=zxR>
set @i=1 VgMuX3=
while @i<30 0kaMYV?
begin Kp6%=JjO
insert into test (userid) values(@i) 3Q_)Xs
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set @i=@i+1 )b,FE}YX
end hO(A_Bw
小记存储过程中经常用到的本周,本月,本年函数 ZC)m&V1
Dateadd(wk,datediff(wk,0,getdate()),-1) `-5gsJ
Dateadd(wk,datediff(wk,0,getdate()),6) 35YDP|XZb
Dateadd(mm,datediff(mm,0,getdate()),0) @ZtvpL}e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) 4!Lj\.!$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) R%Xz3Z&|
上面的SQL代码只是一个时间段 ZsGJ[
Dateadd(wk,datediff(wk,0,getdate()),-1) :* J!
Dateadd(wk,datediff(wk,0,getdate()),6) 5w</Ga
就是表示本周时间段. 9dp1NjOtAc
下面的SQL的条件部分,就是查询时间段在本周范围内的: #YSFiy:+r_
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) }jYVB|2
而在存储过程中 isz-MP$:K5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) {-yw@Kq
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) YyC$\HH6