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。 hHCzj*5
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一、基础 g})6V
1、说明:创建数据库 5/tj
CREATE DATABASE database-name ] xb]8]
2、说明:删除数据库 sS-W~u|C
drop database dbname 2H[=lY
3、说明:备份sql server D!X>O}
--- 创建 备份数据的 device
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USE master $4DFgvy$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Vu_&~z7h
--- 开始 备份 Z"-ntx#
BACKUP DATABASE pubs TO testBack 4pLQ"&>}80
4、说明:创建新表 f( ]R/'o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]}p2Tp;1
根据已有的表创建新表: RV(
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A:create table tab_new like tab_old (使用旧表创建新表) %I_&Ehu
B:create table tab_new as select col1,col2... from tab_old definition only GXarUj s
5、说明:删除新表 Yr5iZ~V$
drop table tabname Y_$^:LG
6、说明:增加一个列 *4-r`k|@>/
Alter table tabname add column col type Ok*VQKyDLH
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 `@4 2jG}*
7、说明:添加主键: Alter table tabname add primary key(col) :-$cdZ3E
说明:删除主键: Alter table tabname drop primary key(col) 2IKxh
8、说明:创建索引:create [unique] index idxname on tabname(col....) g4zT(,ZY
删除索引:drop index idxname }Vs~RJM)}
注:索引是不可更改的,想更改必须删除重新建。 ^?E^']H)5u
9、说明:创建视图:create view viewname as select statement ARmu{cL
删除视图:drop view viewname kSLSxfR
10、说明:几个简单的基本的sql语句 Tq9,c#}&
选择:select * from table1 where 范围 9+]ZH.(YE
插入:insert into table1(field1,field2) values(value1,value2) F"-S~I7'L
删除:delete from table1 where 范围 [Xs}FJ
更新:update table1 set field1=value1 where 范围 2dv|6p
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 2.^7?ok
排序:select * from table1 order by field1,field2 [desc] QV`X?m
总数:select count as totalcount from table1 oN.Mra]D
求和:select sum(field1) as sumvalue from table1 /Lq;w'|I
平均:select avg(field1) as avgvalue from table1 :X3rd|;kc
最大:select max(field1) as maxvalue from table1 :jZ*,d%1={
最小:select min(field1) as minvalue from table1 w~bG<kxP
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11、说明:几个高级查询运算词 fGu5%T,
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A: UNION 运算符 ?whRlh
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。 o%kSR ]V|
B: EXCEPT 运算符 0-8ELX[#
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。 (1j(*
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C: INTERSECT 运算符 ~0VwF
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。 H=JP3ID>{
注:使用运算词的几个查询结果行必须是一致的。 yC9:sQ'k
12、说明:使用外连接 Jm{As*W>
A、left outer join: RM?_15m
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。 |u?k-,uI9
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 sW>P-
B:right outer join: m
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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。 9Q
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C:full outer join: ')5jllxv
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。 dg!1wD
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二、提升 UDIac;vT
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ZaEBdBv
法一:select * into b from a where 1<>1 &(z8GYBr
法二:select top 0 * into b from a :kf3_?9rc
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +1JZB*W
insert into b(a, b, c) select d,e,f from b; Apw-7*/
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) !5g)3St
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `4"y#Z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^)eessZ
4、说明:子查询(表名1:a 表名2:b) MkluK=$
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) (HTk;vbZm
5、说明:显示文章、提交人和最后回复时间 iTKG,$G
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7085&\9
6、说明:外连接查询(表名1:a 表名2:b) R
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3&
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7、说明:在线视图查询(表名1:a ) ?aui q
select * from (SELECT a,b,c FROM a) T where t.a > 1; {cFei3'q
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ?CC6/bE-{
select * from table1 where time between time1 and time2 iD~s,
select a,b,c, from table1 where a not between 数值1 and 数值2 ub&1L_K
9、说明:in 的使用方法 `y(3:##p
select * from table1 where a [not] in ('值1','值2','值4','值6') &}ow-u9c3
10、说明:两张关联表,删除主表中已经在副表中没有的信息 P!/8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) X"]ZV]7(]s
11、说明:四表联查问题: 622).N4
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... l;ugrAo?
12、说明:日程安排提前五分钟提醒 ()Z$j,2
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $A,=z
13、说明:一条sql 语句搞定数据库分页 FpEdwzBb<
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 G[mYx[BTz
14、说明:前10条记录 FVHL;J]nf1
select top 10 * form table1 where 范围 jB;+tDC!Co
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) e)M1$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) sQkP@Y
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 20qT1!ju
(select a from tableA ) except (select a from tableB) except (select a from tableC) F=#Wfl-o
17、说明:随机取出10条数据 &1&*(oi]X
select top 10 * from tablename order by newid() A8?>V%b[Y
18、说明:随机选择记录 VC@o]t5
select newid() anbr3L[!
19、说明:删除重复记录 8447hb?W$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) A6d+RAx
20、说明:列出数据库里所有的表名 G8SJ<\?
select name from sysobjects where type='U' V\_
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21、说明:列出表里的所有的 ^6=nL<L
select name from syscolumns where id=object_id('TableName') B\6\QQ;rUo
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。 \<5xf<{
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 xn-n{U"
显示结果: 8ViDh
type vender pcs '&`Zy pq
电脑 A 1 FY'f{gD^
电脑 A 1 MKbW^:
光盘 B 2 w$p v
光盘 A 2 8WAg{lVs
手机 B 3 qU"+0t4
手机 C 3 A
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23、说明:初始化表table1 }}
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TRUNCATE TABLE table1 fE(rDQI
24、说明:选择从10到15的记录 +iXA|L9=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?vXy7y&4
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三、技巧 z=!xN5
1、1=1,1=2的使用,在SQL语句组合时用的较多 :5ji.g* 0
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !nTq"d%(W
如: @Fo0uy\G
if @strWhere !='' 8 }-"&-X
begin MQhL>oQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5@i/4%S
end *b> ~L
else .7oz
begin 2 Y%$6NX
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' y0Ag px
end N/Z<v* i"
我们可以直接写成 !bQ5CB
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KX{ S8_
2、收缩数据库 4\t9(_
--重建索引 3^8%/5$v
DBCC REINDEX y6$5meh.T
DBCC INDEXDEFRAG ibEQ5 2
--收缩数据和日志 z55P~p
DBCC SHRINKDB /KH3v!G0
DBCC SHRINKFILE 9kTU|py
3、压缩数据库 HuG|BjP
dbcc shrinkdatabase(dbname) p=T]%k*^h#
4、转移数据库给新用户以已存在用户权限 Tf` ~=fg%
exec sp_change_users_login 'update_one','newname','oldname' 41$7P[M;
go :h" Y >1P
5、检查备份集 jytfGE:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9^XT,2Wwf
6、修复数据库 \=1k29O
ALTER DATABASE [dvbbs] SET SINGLE_USER Y!}BmRLh2
GO +tl&Jjdm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK '\P6NszY~
GO *joM[ML` 6
ALTER DATABASE [dvbbs] SET MULTI_USER %*zgN[/w
GO V9][a
7、日志清除 d.sxB}_O
SET NOCOUNT ON g?)9zJ9
DECLARE @LogicalFileName sysname, a~WtW]
@MaxMinutes INT, 0Kq\ oMn
@NewSize INT &?v^xAr?B
USE tablename -- 要操作的数据库名 xrS;06$
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "4zTP!Ow
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zN0^FXGD
@NewSize = 1 -- 你想设定的日志文件的大小(M) =T!iM2
-- Setup / initialize ]&jXD=a"
DECLARE @OriginalSize int S!0<aFh
SELECT @OriginalSize = size skf7Si0z
FROM sysfiles Y 8EL
WHERE name = @LogicalFileName ,aU_bve
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \GEFhM4)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + MZv In ZS
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
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FROM sysfiles
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WHERE name = @LogicalFileName km|;T!
CREATE TABLE DummyTrans D<$,v(-
(DummyColumn char (8000) not null) X3P~z8_
DECLARE @Counter INT, mR)Xq=
@StartTime DATETIME, 7LbBS:@3z_
@TruncLog VARCHAR(255) qk<(iVUO
SELECT @StartTime = GETDATE(), sB"Oi|#lk
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ZBUEg7c
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ,6uON@
EXEC (@TruncLog) L'iENZI$
-- Wrap the log if necessary. GWsvN&nr
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _0Qp[l-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) E_[|ZrIO&*
AND (@OriginalSize * 8 /1024) > @NewSize {N42z0c
BEGIN -- Outer loop. 1Rg tZp%
SELECT @Counter = 0 UzTFT:\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) '[Ap/:/UY
BEGIN -- update &@p _g8r#
INSERT DummyTrans VALUES ('Fill Log') DO`
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DELETE DummyTrans b{%p
SELECT @Counter = @Counter + 1 M=:!d$c
END -.<fGhmU
EXEC (@TruncLog) E!nEB(FD
END R9@Dd
SELECT 'Final Size of ' + db_name() + ' LOG is ' + AqnDsr!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + $a.fQ<,\X
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \]uD"Jqv#
FROM sysfiles -5B>2K F
WHERE name = @LogicalFileName BPs|qb-
DROP TABLE DummyTrans tUU`R{=(
SET NOCOUNT OFF Gmi ^2?Z(
8、说明:更改某个表 %Z_/MNI
exec sp_changeobjectowner 'tablename','dbo' B?n
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9、存储更改全部表 a@4
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch tQ~vLPi$
@OldOwner as NVARCHAR(128), PIOG|E
@NewOwner as NVARCHAR(128) .\)`Xj[?
AS 5^lFksZ
DECLARE @Name as NVARCHAR(128) R<(kiD\?]
DECLARE @Owner as NVARCHAR(128) w(Jf;[o
DECLARE @OwnerName as NVARCHAR(128) NN>E1d=
DECLARE curObject CURSOR FOR Rn?Yz^
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select 'Name' = name, 3<F\5|
'Owner' = user_name(uid) r:N =?X`N
from sysobjects $[(amj-;l
where user_name(uid)=@OldOwner {o>51fXc)
order by name H#/ #yVw
OPEN curObject V Ioqn$
FETCH NEXT FROM curObject INTO @Name, @Owner 0SS,fs<w3
WHILE(@@FETCH_STATUS=0) c?(;6$ A
BEGIN -nK\+bTL}
if @Owner=@OldOwner M9~eDw'Pr
begin B|I9Ex~L
set @OwnerName = @OldOwner + '.' + rtrim(@Name) =#=<%HPT
exec sp_changeobjectowner @OwnerName, @NewOwner oyw*Z_ 9~
end R;d)I^@
-- select @name,@NewOwner,@OldOwner ^lvYj
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FETCH NEXT FROM curObject INTO @Name, @Owner dMd2a4
END I}^Q u0ub
close curObject LOO<)XFJ
deallocate curObject "%zb>`1s
GO ,]Gi942
10、SQL SERVER中直接循环写入数据 #!.26RM:P
declare @i int mv,p*0
set @i=1 _s{;9&qX]
while @i<30 t GS>f>i
begin Ty&Ok*
insert into test (userid) values(@i) 2K:Rrn/cR
set @i=@i+1 1
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end 0%(.$c>:f
小记存储过程中经常用到的本周,本月,本年函数 /`kM0=MMa
Dateadd(wk,datediff(wk,0,getdate()),-1) D`4>Wh/H
Dateadd(wk,datediff(wk,0,getdate()),6) )swu~Wb}U@
Dateadd(mm,datediff(mm,0,getdate()),0) cM?i _m
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) faIHmU
Dateadd(yy,datediff(yy,0,getdate()),0) ~fF_]UVq3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) j+eto'
上面的SQL代码只是一个时间段 /_(q7:<ZF
Dateadd(wk,datediff(wk,0,getdate()),-1) dy'
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Dateadd(wk,datediff(wk,0,getdate()),6) ?mi1PNps#
就是表示本周时间段. E+"m@63
下面的SQL的条件部分,就是查询时间段在本周范围内的: a(#aEbN?d
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) x{_3/4
而在存储过程中 360b`zS
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Wm^RfxgN/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 3:g~@PB