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。 SgQ(#y|vV
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一、基础 8>|<m'e^\r
1、说明:创建数据库 $|I hO
CREATE DATABASE database-name nHQWO
2、说明:删除数据库 !#PA#Q|cO
drop database dbname (Y
3、说明:备份sql server RAA,%rRhu(
--- 创建 备份数据的 device 43*;" w=
USE master UW{C`^?=B
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -+:t%A?
--- 开始 备份 R=S)O.*R
BACKUP DATABASE pubs TO testBack EfX,0Nq T
4、说明:创建新表 cEK#5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) P9M%B2DQ6f
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) hcR^?
B:create table tab_new as select col1,col2... from tab_old definition only 5m?9O7Pg
5、说明:删除新表 Q5*"t*L!N
drop table tabname ">q?(i\
6、说明:增加一个列 P&*e\"{
Alter table tabname add column col type 'wo}1^V
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 `_OB_F
7、说明:添加主键: Alter table tabname add primary key(col) {z@a{L:SC
说明:删除主键: Alter table tabname drop primary key(col) Q'aVdJN,
8、说明:创建索引:create [unique] index idxname on tabname(col....) ov1#BeQ
删除索引:drop index idxname ob9=/ R?i
注:索引是不可更改的,想更改必须删除重新建。 Xvxrz{
9、说明:创建视图:create view viewname as select statement ,v#3A7"yW
删除视图:drop view viewname 0hq\{pw_y*
10、说明:几个简单的基本的sql语句 UGP&&A#T-
选择:select * from table1 where 范围 it->)?"(6
插入:insert into table1(field1,field2) values(value1,value2) ]G,BSttD
删除:delete from table1 where 范围 E4<#6q
更新:update table1 set field1=value1 where 范围 g+-^6UG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! dlMjy$/T
排序:select * from table1 order by field1,field2 [desc] w^[:wzF0
总数:select count as totalcount from table1 sc z8`%
求和:select sum(field1) as sumvalue from table1 .G>~xm0
平均:select avg(field1) as avgvalue from table1 t6~~s
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最大:select max(field1) as maxvalue from table1 ogoEtKi
最小:select min(field1) as minvalue from table1 J4?SC+\
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11、说明:几个高级查询运算词 xN6}4JB
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A: UNION 运算符 R xc
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。 G9CL}=lJ,
B: EXCEPT 运算符 J!yK/*sO,
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。 M[L@ej
C: INTERSECT 运算符 8]WcW/1r !
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。 5[P^O6'
注:使用运算词的几个查询结果行必须是一致的。 h@Ix9!?+
12、说明:使用外连接 jgBJs^JgYG
A、left outer join: n%6=w9.%c
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。 H^g&e$d0
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 Vr #o]v
B:right outer join: 7/dp_I}cO
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。 b6'ZVB
C:full outer join: afjEN
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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。 @Suww@<
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二、提升 !ozHS_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9 $zx<O
法一:select * into b from a where 1<>1 vyT-!mC
法二:select top 0 * into b from a $LtCI
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >n%ckL|rG
insert into b(a, b, c) select d,e,f from b; Kp6%=JjO
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) 3Q_)Xs
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )b,FE}YX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hO(A_Bw
4、说明:子查询(表名1:a 表名2:b) ZC)m&V1
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) `-5gsJ
5、说明:显示文章、提交人和最后回复时间 35YDP|XZb
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @ZtvpL}e
6、说明:外连接查询(表名1:a 表名2:b) j{HIdP
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _+ >V(,{G
7、说明:在线视图查询(表名1:a ) ;>Z0e`=
select * from (SELECT a,b,c FROM a) T where t.a > 1; vH6.;j'^
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 TU9$5l/;g
select * from table1 where time between time1 and time2 N'?#g`*KW
select a,b,c, from table1 where a not between 数值1 and 数值2 K\5/ ||gi
9、说明:in 的使用方法 ge%tj O
select * from table1 where a [not] in ('值1','值2','值4','值6') 3&B- w
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (>gb9n
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 'fY29Xr^
11、说明:四表联查问题: H
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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 ..... ;Ehv1{;
12、说明:日程安排提前五分钟提醒 m4G))||9Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 K^%ONultv
13、说明:一条sql 语句搞定数据库分页 4"Mq]_D
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 LKst
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14、说明:前10条记录 B8zc#0!1
select top 10 * form table1 where 范围 `bZgw
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.) ^C;ULUn3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) H~W=#Cx
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 GsIqUM#R
(select a from tableA ) except (select a from tableB) except (select a from tableC) qrcir-+
17、说明:随机取出10条数据 yRt7&,}zL
select top 10 * from tablename order by newid() MkM`)g 5
18、说明:随机选择记录 #X0Y8:vj
select newid() 1c4:'0
19、说明:删除重复记录 %5j*e
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2QKt.a
20、说明:列出数据库里所有的表名
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select name from sysobjects where type='U' E+Dcw
21、说明:列出表里的所有的 9M@,BXOt
select name from syscolumns where id=object_id('TableName') @[]#[7
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。 %4Yq
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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 \Z-Fu=8J8^
显示结果: ^[b DE0
type vender pcs M/YS%1
电脑 A 1 (.kzJ\x
电脑 A 1 HaQox.v%
光盘 B 2 ccy q~
光盘 A 2 .v['INK9
手机 B 3 o RK:{?Y
手机 C 3 %t]{C06w+{
23、说明:初始化表table1 Z5[g[Q
TRUNCATE TABLE table1 Ce} m_
24、说明:选择从10到15的记录 Uf~5Fc1d =
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc LB^xdMXi
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三、技巧 5)ooE
1、1=1,1=2的使用,在SQL语句组合时用的较多 a&B@F]+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '>t'U?7w<
如: 5`q#~fJ2
if @strWhere !='' 1?,C d
begin p,7?rI\N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~\ v"xV
end WpC9(AX5g
else q<4{&omUJ
begin }bnodb^.7
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' S(_DR8
end EEiWIf&S,
我们可以直接写成 DDZnNSo<JQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 1tl qw
2、收缩数据库 vZXdc+2l
--重建索引 @6H 7
DBCC REINDEX S]Aaf-X_
DBCC INDEXDEFRAG br*PB]dU
--收缩数据和日志 &5hs
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DBCC SHRINKDB Uv!VzkPfo
DBCC SHRINKFILE ]2MX7
3、压缩数据库 Y.%Vvg4z3
dbcc shrinkdatabase(dbname) ]^<\a=U
4、转移数据库给新用户以已存在用户权限 ^[Y/ +Q.J
exec sp_change_users_login 'update_one','newname','oldname' 8qoA5fW>
go z<8VJZd
5、检查备份集 Ei89Ngp\}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3Qu-X\
6、修复数据库 T[2<_ nn=
ALTER DATABASE [dvbbs] SET SINGLE_USER sk@aOv'*(
GO d"thM
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK nY,LQ0r
GO |Gr@Mi5
ALTER DATABASE [dvbbs] SET MULTI_USER P[r$KGz
GO TNF
7、日志清除 c!mMH~#
SET NOCOUNT ON WnA
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DECLARE @LogicalFileName sysname, =Ea,8bpn
@MaxMinutes INT, {8,_[?H
@NewSize INT SZvC4lOn#
USE tablename -- 要操作的数据库名 dcfwUjp[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 w4l]rH
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4|DN^F~iut
@NewSize = 1 -- 你想设定的日志文件的大小(M) .p(r|5(b
-- Setup / initialize l0tFj>q"
DECLARE @OriginalSize int t|*UlTLm
SELECT @OriginalSize = size G^#?~
FROM sysfiles [C@Ro,mI
WHERE name = @LogicalFileName 3V<c4'O\W
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2m9qg-W
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }Ggn2 X
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' -jVg{f!
FROM sysfiles 38%"#T3#
WHERE name = @LogicalFileName 7?\r9bD
CREATE TABLE DummyTrans B)rBM
(DummyColumn char (8000) not null) ovaX_d)cU
DECLARE @Counter INT, 7H4kj7UK
@StartTime DATETIME, \jAI~|3
@TruncLog VARCHAR(255) ,C|aiSh0-
SELECT @StartTime = GETDATE(), )))AxgM
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?',Wn3A
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \\35}
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EXEC (@TruncLog) TV}=$\D
-- Wrap the log if necessary. ^=qV)j
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Omph(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^}lL@Bd|
AND (@OriginalSize * 8 /1024) > @NewSize $SfY<j,R
BEGIN -- Outer loop. c*R18,5-
SELECT @Counter = 0 ?\zyeWK0L
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) hPUZ{#;n
BEGIN -- update ?"@SxM~\
INSERT DummyTrans VALUES ('Fill Log') {ea*dX872:
DELETE DummyTrans Zt
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SELECT @Counter = @Counter + 1 H7f
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END wV,=hMTd&\
EXEC (@TruncLog) qJw\<7m
END 2FGCf} ,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ?i}wm`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2~hQ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' s:I 8~Cc
FROM sysfiles JC}T*h>Ee
WHERE name = @LogicalFileName 6mjD@
DROP TABLE DummyTrans `0-i>>
SET NOCOUNT OFF 5'_:>0}
8、说明:更改某个表 ;|f]e/El
exec sp_changeobjectowner 'tablename','dbo' 0\+$j5;
9、存储更改全部表 ac8su0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )4H0Bz2G
@OldOwner as NVARCHAR(128), ,? Q1JZPy@
@NewOwner as NVARCHAR(128) 7r pTk&`
AS sR| /s3;
DECLARE @Name as NVARCHAR(128) biVsbxYurq
DECLARE @Owner as NVARCHAR(128) Gi&/`vm
DECLARE @OwnerName as NVARCHAR(128) (V"7H
DECLARE curObject CURSOR FOR A[f`xE
select 'Name' = name, B0^:nYko
'Owner' = user_name(uid) w<Iq:3
from sysobjects y tTppmJF
where user_name(uid)=@OldOwner U[:Js@uH_
order by name Kc+9n%sp
OPEN curObject 5"D\n B%
FETCH NEXT FROM curObject INTO @Name, @Owner Ef=4yH?\j
WHILE(@@FETCH_STATUS=0) {6F]w_\
BEGIN Dc] J3r
if @Owner=@OldOwner NC|VZwQtm
begin 1h`# H:
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fm Fs
exec sp_changeobjectowner @OwnerName, @NewOwner
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end Hq,znRz~`
-- select @name,@NewOwner,@OldOwner ;9qwB
FETCH NEXT FROM curObject INTO @Name, @Owner !0cb f&^:
END xww\L
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close curObject OGW0lnQ/
deallocate curObject u2*."W\
GO $C8s
10、SQL SERVER中直接循环写入数据 q2M%AvR
declare @i int P+,YWp
set @i=1 #*G}v%Ow/u
while @i<30 >jc17BJq
begin !ce,^z&5
insert into test (userid) values(@i) %}{.U
set @i=@i+1 U)1hC^[!
end =BzBM`-o
小记存储过程中经常用到的本周,本月,本年函数 VGOdJ|2]Wr
Dateadd(wk,datediff(wk,0,getdate()),-1) 8,:lw3x1
Dateadd(wk,datediff(wk,0,getdate()),6) Gn<e&|4>i}
Dateadd(mm,datediff(mm,0,getdate()),0) pzU:AUW
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \G6V -W
Dateadd(yy,datediff(yy,0,getdate()),0) M*F`s&vM
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ,MD>Jx|
上面的SQL代码只是一个时间段 YwJ<0;:+hS
Dateadd(wk,datediff(wk,0,getdate()),-1) :oJ!9\5
Dateadd(wk,datediff(wk,0,getdate()),6) UQjZhH
就是表示本周时间段. RI]x=
下面的SQL的条件部分,就是查询时间段在本周范围内的: $EZr@n
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) h5[.G!
而在存储过程中 ^_o:Ddz?l"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) = Ruq
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) !1P<A1K