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。 j
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一、基础 j,
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1、说明:创建数据库 +~P_o_M
CREATE DATABASE database-name ~>_UTI
2、说明:删除数据库 Brd9"M|d
drop database dbname PRBlf
3、说明:备份sql server =w:)AWZ
--- 创建 备份数据的 device o9C#5%9
USE master +M#}(hK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' A@:U|)+4
--- 开始 备份 Nq6;
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BACKUP DATABASE pubs TO testBack !I&,!$
4、说明:创建新表 P1^|r}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3xdJ<Lrq
根据已有的表创建新表: )%kiM<})
A:create table tab_new like tab_old (使用旧表创建新表) @J qo'\~&
B:create table tab_new as select col1,col2... from tab_old definition only M0?%r`
5、说明:删除新表 ly_8p63-
drop table tabname A>mk0P)~Q
6、说明:增加一个列 Akws I@@
Alter table tabname add column col type >lyE@S sA
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。 -eD]gm
7、说明:添加主键: Alter table tabname add primary key(col)
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说明:删除主键: Alter table tabname drop primary key(col) 1_;{1O+B
8、说明:创建索引:create [unique] index idxname on tabname(col....) *(5T?p[7
删除索引:drop index idxname D#`>p
注:索引是不可更改的,想更改必须删除重新建。 0%q H=do6
9、说明:创建视图:create view viewname as select statement se]&)%p[
删除视图:drop view viewname -0]%#(E%`h
10、说明:几个简单的基本的sql语句 ?1O`
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选择:select * from table1 where 范围 BG.sHI{
插入:insert into table1(field1,field2) values(value1,value2) Z.x]6
删除:delete from table1 where 范围 3Of!Ykf=
更新:update table1 set field1=value1 where 范围 9%"\s2T
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {Xr 9]g`
排序:select * from table1 order by field1,field2 [desc] |QR9#Iv
总数:select count as totalcount from table1 ]Wjcr2Wq
求和:select sum(field1) as sumvalue from table1 ;R<V-gab
平均:select avg(field1) as avgvalue from table1 ,!PV0(F(
最大:select max(field1) as maxvalue from table1 B&1E&Cv_8
最小:select min(field1) as minvalue from table1 f87XE";:A
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11、说明:几个高级查询运算词 lF40n4}
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A: UNION 运算符 5DkEJk7a
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。 "3a}~J<g
B: EXCEPT 运算符 ?|
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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。 -okq=9
C: INTERSECT 运算符 F!4V!VWA}
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。 \}Iq-Je
注:使用运算词的几个查询结果行必须是一致的。 Y7I\<JG<
12、说明:使用外连接 0V^I.S/q
A、left outer join: tTubW=H
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。 CBpwtI>p
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 iE_[]Vgc
B:right outer join: ma<uXq
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。 6R$Yh0%
C:full outer join: o-AF_N
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。 ]ZW-`U MO
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二、提升 xD~r Q$6sI
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~Je40vO[
法一:select * into b from a where 1<>1 x%[NK[^&
法二:select top 0 * into b from a hsYE&Np_Q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) UlNV%34"
insert into b(a, b, c) select d,e,f from b; mI:^lp
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) \IudS{
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M`@AS L:u
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. fgC@(dvfk
4、说明:子查询(表名1:a 表名2:b) gSj0+|
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) B%kC>J
5、说明:显示文章、提交人和最后回复时间 `
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b AGjjhbGB
6、说明:外连接查询(表名1:a 表名2:b) >ZeARCf"f
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c TXf60{:f
7、说明:在线视图查询(表名1:a ) Z5*(xony0
select * from (SELECT a,b,c FROM a) T where t.a > 1; N[fwd=$\#
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 xirq$sEl
select * from table1 where time between time1 and time2 L<B)BEE.
select a,b,c, from table1 where a not between 数值1 and 数值2 ^Pu:&:ki
9、说明:in 的使用方法 $d4&H/u^
select * from table1 where a [not] in ('值1','值2','值4','值6') ^K_FGE0ec
10、说明:两张关联表,删除主表中已经在副表中没有的信息 h;y}g/HZ
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Qe4 % A
11、说明:四表联查问题: rl$"~/ oz
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 ..... ,S<) )
12、说明:日程安排提前五分钟提醒 s16, *;Z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 H8HVmfM
13、说明:一条sql 语句搞定数据库分页 HD2C^V2@M
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 2Qh)/=8lM
14、说明:前10条记录 '$'a .q1q9
select top 10 * form table1 where 范围 ct
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ""|;5kJS4
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) lFSvHs5
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 9vwm
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(select a from tableA ) except (select a from tableB) except (select a from tableC) [F;\NJp6?^
17、说明:随机取出10条数据 mE>{K
select top 10 * from tablename order by newid() E`hR(UL
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18、说明:随机选择记录 Y|J=72!]
select newid() W\5 -Yg(@
19、说明:删除重复记录 mpVD;)?JmM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2mMi=pv9
20、说明:列出数据库里所有的表名 r ?<kWR?w
select name from sysobjects where type='U' Gr)G-zE
21、说明:列出表里的所有的 \&ZEIAe
select name from syscolumns where id=object_id('TableName') j8PeO&n>
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 !>=lah$&
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 U /~uu
显示结果: q8;MPXSG3
type vender pcs 4`fV_H.8
电脑 A 1 k'PvQl"I
电脑 A 1 a^E>LJL
光盘 B 2 Sl'$w4s
光盘 A 2 kzNRRs\e
手机 B 3 KK4e'[Wf
手机 C 3 (!J;g|58
23、说明:初始化表table1 ^8]7
TRUNCATE TABLE table1 :F#^Q%-IS
24、说明:选择从10到15的记录 Q-#<{' (
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #h
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三、技巧 *PB /I4>{
1、1=1,1=2的使用,在SQL语句组合时用的较多 BS,EW
"where 1=1" 是表示选择全部 "where 1=2"全部不选, &5bIM>)v
如: @Bjp7v:w
if @strWhere !='' 0=t2|,}
begin .J&89I]U
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S'w}Ir
end Y
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else 05\0g9
begin .a(G=fk
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }$qrNbLJ
end GM1.pVb
我们可以直接写成 n9k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Nh/i'q/
2、收缩数据库 *qAG0EM|
--重建索引 vWrTB
DBCC REINDEX ?EPHq,
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DBCC INDEXDEFRAG hA1B C3
--收缩数据和日志 + @|u8+
DBCC SHRINKDB W/ WP }QM
DBCC SHRINKFILE e6tU8`z
3、压缩数据库 +]NpcE'
dbcc shrinkdatabase(dbname) W&D{0 i`y
4、转移数据库给新用户以已存在用户权限 #R31VQwK5
exec sp_change_users_login 'update_one','newname','oldname' R^sgafGl=
go Z(tO]tQE
5、检查备份集 ZNk[Jn
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ,/TmTX--d
6、修复数据库 NZADHO@0
ALTER DATABASE [dvbbs] SET SINGLE_USER .f. tPm
GO nN@
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK E_[a|N"D
GO z8%qCq
ALTER DATABASE [dvbbs] SET MULTI_USER zSk`Ou8M
GO %[9ty`UE
7、日志清除 MtF0/aT
SET NOCOUNT ON lcy+2)+
DECLARE @LogicalFileName sysname, qwnVtD
@MaxMinutes INT, -)Vy)hD,
@NewSize INT ZqpK}I
USE tablename -- 要操作的数据库名 c=bK_Z_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Hg8
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. bj 8pqw|;
@NewSize = 1 -- 你想设定的日志文件的大小(M) z7L+wNYwg
-- Setup / initialize !wfUD2K1
DECLARE @OriginalSize int .f;@OqU
SELECT @OriginalSize = size u*uHdV5
FROM sysfiles dn?'06TD
WHERE name = @LogicalFileName a.JjbFL
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |22vNt_
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `'EG7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' qdKqc,R1{
FROM sysfiles 3XQe? 2:<
WHERE name = @LogicalFileName 5 $$Cav
CREATE TABLE DummyTrans X%JyC_~<
(DummyColumn char (8000) not null) ].aFdy
DECLARE @Counter INT, 0kls/^ 0,
@StartTime DATETIME, $)PS#ND&
@TruncLog VARCHAR(255) |r?0!;bN0
SELECT @StartTime = GETDATE(), PO0Od z
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' m$(OQ,E
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Mw-L?j0o[k
EXEC (@TruncLog) W?P4oKsql*
-- Wrap the log if necessary. 4${3e
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _5(p=Zc
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +%KkzdS'
AND (@OriginalSize * 8 /1024) > @NewSize Lp@Al#X55
BEGIN -- Outer loop. !TY0;is
SELECT @Counter = 0 *b0z/6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) z
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BEGIN -- update S
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INSERT DummyTrans VALUES ('Fill Log') F0zaA
DELETE DummyTrans _1Ne+"V
SELECT @Counter = @Counter + 1 M2d&7>N
END qTwl\dcncC
EXEC (@TruncLog) n@"<NKzh
END mvt-+K?U
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _LfbEv<,T
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3$:F/H
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' }aXS MxCd
FROM sysfiles ,WnZ^R/n
WHERE name = @LogicalFileName '/9MN;_
DROP TABLE DummyTrans wxj}k7_(`A
SET NOCOUNT OFF J&JZYuuf
8、说明:更改某个表 @W
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exec sp_changeobjectowner 'tablename','dbo' zw$\d1-+h
9、存储更改全部表 mJ5%+.V
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Iw(
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@OldOwner as NVARCHAR(128), Knb(MI6
@NewOwner as NVARCHAR(128) b2[U3)|oO
AS OkISRj'!U
DECLARE @Name as NVARCHAR(128) IuAu_`,Ndi
DECLARE @Owner as NVARCHAR(128) \pTC[Ry1
DECLARE @OwnerName as NVARCHAR(128) O:T
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DECLARE curObject CURSOR FOR |*h{GX.(
select 'Name' = name, |]?W`KN0
'Owner' = user_name(uid) 8f)pf$v`
from sysobjects fi ~@J`
where user_name(uid)=@OldOwner )t7MD(
order by name eX}aa0
OPEN curObject '/0e!x/8
FETCH NEXT FROM curObject INTO @Name, @Owner "zTy_0[;
WHILE(@@FETCH_STATUS=0) h&d"| <
BEGIN gp $Rf9\
if @Owner=@OldOwner xt"-Jmox
begin u(f;4`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +|pYu<OY
exec sp_changeobjectowner @OwnerName, @NewOwner gae=+@z
end 5T( cy
-- select @name,@NewOwner,@OldOwner 7,Z<PE
FETCH NEXT FROM curObject INTO @Name, @Owner ZHeq)5C ;f
END ;/?w-)n?
close curObject t>*(v#WeZ
deallocate curObject 3W#E$^G_v
GO !^0vi3I
10、SQL SERVER中直接循环写入数据 `Je1$)%
declare @i int QOrMz`OA
set @i=1 $""kZ
while @i<30 #=ij</
begin 8No'8(dPX
insert into test (userid) values(@i) `Eu,SvkF w
set @i=@i+1 kv+^U^WoU
end Lw(tO0b2H
小记存储过程中经常用到的本周,本月,本年函数 %0}}Qt
Dateadd(wk,datediff(wk,0,getdate()),-1) 2DJg__("
Dateadd(wk,datediff(wk,0,getdate()),6) L;{{P7
Dateadd(mm,datediff(mm,0,getdate()),0) |#yT]0L%pA
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) eK*oV}U-k
Dateadd(yy,datediff(yy,0,getdate()),0) ,1~zMzw ^
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) @H+L1H%9n
上面的SQL代码只是一个时间段 9(z) ^G
Dateadd(wk,datediff(wk,0,getdate()),-1) [E6ceX0
Dateadd(wk,datediff(wk,0,getdate()),6) e00}YWf%
就是表示本周时间段. hDZyFRg
下面的SQL的条件部分,就是查询时间段在本周范围内的: v.>K
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) l;R8"L:,p\
而在存储过程中 jA^Dk$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 9b,0_IMHH
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 5=<KA