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。 =WIJ>#Go<
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一、基础 A A^{B
1、说明:创建数据库 2ZcKK8X;7
CREATE DATABASE database-name zK|i='XSf
2、说明:删除数据库 PjKECN
drop database dbname ^r6!l.
3、说明:备份sql server ;&V s4
--- 创建 备份数据的 device w[tmCn+
USE master }e2VY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' vS\Nd1~ ?
--- 开始 备份 SAYLG
BACKUP DATABASE pubs TO testBack ZJPmR/OV_
4、说明:创建新表 HpZ1xT
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) N@ \&1I`c$
根据已有的表创建新表: EU7|,>a
A:create table tab_new like tab_old (使用旧表创建新表) V!v:]E
B:create table tab_new as select col1,col2... from tab_old definition only f| _u7"OX
5、说明:删除新表 5"XC$?I<}
drop table tabname PHOP%hI$
6、说明:增加一个列 0k)rc$eDF+
Alter table tabname add column col type Q7Iw[=;\
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 fGhn+8VfX
7、说明:添加主键: Alter table tabname add primary key(col) v6.t{6zYgY
说明:删除主键: Alter table tabname drop primary key(col) 'k;rH!R
8、说明:创建索引:create [unique] index idxname on tabname(col....) s\!>"J bAQ
删除索引:drop index idxname 3?2 FP|G8
注:索引是不可更改的,想更改必须删除重新建。 oND@:>QBF
9、说明:创建视图:create view viewname as select statement `F<jLU^3
删除视图:drop view viewname G uz"wY
10、说明:几个简单的基本的sql语句 KlRr8G!Z
选择:select * from table1 where 范围 h/?l4iR*
插入:insert into table1(field1,field2) values(value1,value2) ls@i".[
删除:delete from table1 where 范围 p
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更新:update table1 set field1=value1 where 范围 c\a_VRN>r
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! '5&s=M_
排序:select * from table1 order by field1,field2 [desc] .<@8gNm3
总数:select count as totalcount from table1 #@<9S{F
求和:select sum(field1) as sumvalue from table1 [8tL"G6s
平均:select avg(field1) as avgvalue from table1 _SW3_8SuM.
最大:select max(field1) as maxvalue from table1 BauU{:Sh
最小:select min(field1) as minvalue from table1 C8
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:#@ = B]
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11、说明:几个高级查询运算词 PDs@?nz,
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A: UNION 运算符 '>r7V
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Ym3\pRFiD
B: EXCEPT 运算符 94B\5I}
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 hzk cP
C: INTERSECT 运算符 'yMF~r3J
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ggJO:$?$L
注:使用运算词的几个查询结果行必须是一致的。 *S2ypzwRZ,
12、说明:使用外连接 O,Cb"{qH8
A、left outer join: nBk)WX&[K
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 u\C
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `
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B:right outer join: t+9][Adf
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 v`M3eh@$A
C:full outer join: X5j1`t,
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。 Djg,Lvhm
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二、提升 ^]TVo\,N
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) c%MW\qx
法一:select * into b from a where 1<>1 l1f\=G?tmU
法二:select top 0 * into b from a %i5M77#Z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \otWd
insert into b(a, b, c) select d,e,f from b; 8ji_#og
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) gLOEh6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 30SW\@
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. y&V@^"`
4、说明:子查询(表名1:a 表名2:b) 9I4K}R
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) rk #sy$
5、说明:显示文章、提交人和最后回复时间 ax (c#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V#iPj'*
6、说明:外连接查询(表名1:a 表名2:b) E{|W(z,
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R6]Gk)5
7、说明:在线视图查询(表名1:a ) 6_FE 4RR[
select * from (SELECT a,b,c FROM a) T where t.a > 1; EM[WK+9>I{
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 DQr Y*nH
select * from table1 where time between time1 and time2 \--8lH -K
select a,b,c, from table1 where a not between 数值1 and 数值2 3.*8)NW
9、说明:in 的使用方法 lhqg$lb
select * from table1 where a [not] in ('值1','值2','值4','值6') ;C2K~8,
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #w' kV#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [Al&
11、说明:四表联查问题: INJEsz
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... cLLbZ=`
12、说明:日程安排提前五分钟提醒 NxsBX:XDn
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !wNr3LG
13、说明:一条sql 语句搞定数据库分页 2.l:O2<
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ]7RD"}
14、说明:前10条记录 d8c=L8~jt
select top 10 * form table1 where 范围 R^Y
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ?.Ca|H<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) s+<Yg$)
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 i%0ur}p
(select a from tableA ) except (select a from tableB) except (select a from tableC) EwvoQ$#jv
17、说明:随机取出10条数据 g\&g N
select top 10 * from tablename order by newid() a ?)NC
18、说明:随机选择记录 AJF#Aw `o
select newid() ivN&HAxI@
19、说明:删除重复记录 f=WDR m]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =,6z4" )
20、说明:列出数据库里所有的表名 y~U #veY
select name from sysobjects where type='U' pe1R(|H
21、说明:列出表里的所有的 :g Wu9Y|{
select name from syscolumns where id=object_id('TableName') $xPaYf
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 (&F
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ZZzMO6US0
显示结果: pC@{DW;V6R
type vender pcs 5Ou`z5S\k
电脑 A 1 woK&q 7Vn
电脑 A 1 {+Rog/;S'
光盘 B 2 8~@c)Z;
光盘 A 2 62ws/8d6f
手机 B 3 Yp^rR }N
手机 C 3 <+?7H\b
23、说明:初始化表table1 + |n*b
TRUNCATE TABLE table1 hG12ZZ D
24、说明:选择从10到15的记录 EVsC >rz
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc f'EuY17w
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三、技巧 42$VhdG
1、1=1,1=2的使用,在SQL语句组合时用的较多 Ch<[l8;K
"where 1=1" 是表示选择全部 "where 1=2"全部不选, "&G/T ?4
如: Ku5\]
if @strWhere !=''
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begin #P0&ewy
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere r\'A
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end o$jLzE"
else W{6|tx)
begin Y5- F@(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' \/zq7j
end YIQ
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我们可以直接写成 e> e}vZlX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @#T|Y&
2、收缩数据库 @tNz Q8
--重建索引 R;uvkg[o
DBCC REINDEX 8]/bK5`
DBCC INDEXDEFRAG _E@2ZnD2
--收缩数据和日志
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DBCC SHRINKDB cPyE 6\lN
DBCC SHRINKFILE <Tzrj1"Q3
3、压缩数据库 D9^h;
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dbcc shrinkdatabase(dbname) -*X a3/kQ
4、转移数据库给新用户以已存在用户权限 *x@Onj
exec sp_change_users_login 'update_one','newname','oldname' .WA-&b_
go p6>Svcc
5、检查备份集 8lvV4yb
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 7)`nD<j5
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER i&bA2p3+d
GO nP$Ky1y G
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK v_+{'F
GO PUp6Q;AdQ
ALTER DATABASE [dvbbs] SET MULTI_USER H<i]V9r
GO c|e~BQdRw
7、日志清除 [%y';`( x
SET NOCOUNT ON [1g8*j~L
DECLARE @LogicalFileName sysname, AG`L64B
@MaxMinutes INT, A5c%SCq;
@NewSize INT /?5 1D@
USE tablename -- 要操作的数据库名 +Vb.lH[av
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 U)fc*s
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Rr&h!YMb
@NewSize = 1 -- 你想设定的日志文件的大小(M) JjtNP)We
-- Setup / initialize ,<(}|go
DECLARE @OriginalSize int :}'=`wa
SELECT @OriginalSize = size #A1%gIw<v2
FROM sysfiles 6m*QX+
WHERE name = @LogicalFileName ]b2p G'
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^a0um/+M}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @vC4[:"pD}
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' w'Y7IlC
FROM sysfiles Xv ]W(f1
WHERE name = @LogicalFileName FtP0krO(
CREATE TABLE DummyTrans XixL R
(DummyColumn char (8000) not null) 5sj4;w[
DECLARE @Counter INT, 7zXvnxYE
@StartTime DATETIME, kbX8$xTM
@TruncLog VARCHAR(255) 4Tb
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SELECT @StartTime = GETDATE(), 8]M ;T>n[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 'f!8DGix
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Pr':51(
EXEC (@TruncLog) Q{s H3Y#l
-- Wrap the log if necessary. deBY5|
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired wN_Vfb
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 9UdM`v)(
AND (@OriginalSize * 8 /1024) > @NewSize rK' L6o
BEGIN -- Outer loop. =upeRY@u5
SELECT @Counter = 0 u^@f&BIG]:
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) }eCw6
BEGIN -- update > kGGR
INSERT DummyTrans VALUES ('Fill Log') '\l"
DELETE DummyTrans xI #9
SELECT @Counter = @Counter + 1 Qp)v?k ]
END oR)Jznmi}
EXEC (@TruncLog) @Q)OGjaq
END U6glp@s
SELECT 'Final Size of ' + db_name() + ' LOG is ' + kyR:[+je
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2e+UM$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' u@W|gLT1
FROM sysfiles &47i"%
WHERE name = @LogicalFileName /?uPEKr
DROP TABLE DummyTrans >K_(J/&p
SET NOCOUNT OFF [_R~%Yh+'E
8、说明:更改某个表 n`? py
exec sp_changeobjectowner 'tablename','dbo' !,wIQy_e4
9、存储更改全部表 o5Dk:Bw
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Qf~vZtJ+J
@OldOwner as NVARCHAR(128), ~Z\8UsVN
@NewOwner as NVARCHAR(128) ^cOUQ33
AS
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DECLARE @Name as NVARCHAR(128) B]nEkO'a:
DECLARE @Owner as NVARCHAR(128) Y071Y:
DECLARE @OwnerName as NVARCHAR(128) : %lTU
DECLARE curObject CURSOR FOR }MJy
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select 'Name' = name, Jj; L3S
'Owner' = user_name(uid) py$Q
from sysobjects ~qiJR`Jj
where user_name(uid)=@OldOwner }*M6x;t
order by name dN$0OS`s[
OPEN curObject e>} s;H,
FETCH NEXT FROM curObject INTO @Name, @Owner J{.{f
WHILE(@@FETCH_STATUS=0) 0.`/X66;V
BEGIN Z;ht
if @Owner=@OldOwner NO*u9YH?
begin ((YMVe
set @OwnerName = @OldOwner + '.' + rtrim(@Name) v [wb~uw\
exec sp_changeobjectowner @OwnerName, @NewOwner :}He\V
end 7x"R3
-- select @name,@NewOwner,@OldOwner +SP{hHa^
FETCH NEXT FROM curObject INTO @Name, @Owner m~iXl,r
END ]J1dt N=
close curObject VQc_|z_s
deallocate curObject \\iQEy<i
GO &PR5q7
10、SQL SERVER中直接循环写入数据 ]~Rho_mq#
declare @i int JrJo|0Q
set @i=1 ]AINKUI0
while @i<30 O*hDbM2QQw
begin Y+kfBvxyf
insert into test (userid) values(@i) -$pzl,^ h
set @i=@i+1 j@n)kPo,1
end k$ 4y9{
小记存储过程中经常用到的本周,本月,本年函数 Z+*9#!?J
Dateadd(wk,datediff(wk,0,getdate()),-1) td(li.,
Dateadd(wk,datediff(wk,0,getdate()),6) >~''&vdsk\
Dateadd(mm,datediff(mm,0,getdate()),0) AHD=<7Rs
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]0Y4U7W
Dateadd(yy,datediff(yy,0,getdate()),0) OV1_|##LC
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0z`a1 %U
上面的SQL代码只是一个时间段 0!4Ts3qn1
Dateadd(wk,datediff(wk,0,getdate()),-1) /Wi[OT14
Dateadd(wk,datediff(wk,0,getdate()),6) I:=S0&%)
就是表示本周时间段. +^` I?1\UF
下面的SQL的条件部分,就是查询时间段在本周范围内的: QE^$=\l0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Gw}%{=D9
而在存储过程中 n<Z({\9&H
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) tIWmp30S
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) :vmH]{R