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。 $I.'7
&h;
0wx`y$~R
a^22H
一、基础 g
{00i
1、说明:创建数据库 7L!k9"X`0F
CREATE DATABASE database-name qU"+0t4
2、说明:删除数据库 Mqq7;w@(J
drop database dbname .e6 :/x~p*
3、说明:备份sql server ]'"$qm:
--- 创建 备份数据的 device %bAv.'C
USE master DV.m({?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X0m\
--- 开始 备份 d+_qBp
BACKUP DATABASE pubs TO testBack H)5]K9D
4、说明:创建新表 WPPmh~:
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) UW\.!TV
根据已有的表创建新表: BM3nZ<%3
A:create table tab_new like tab_old (使用旧表创建新表) 4u<oe_n
B:create table tab_new as select col1,col2... from tab_old definition only (*|hlD~
5、说明:删除新表 ]1klfp,`
drop table tabname x{=ty*E
6、说明:增加一个列 @Fo0uy\G
Alter table tabname add column col type XRZmg "
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 HxkhlNB
7、说明:添加主键: Alter table tabname add primary key(col) ,ujoGSx}
说明:删除主键: Alter table tabname drop primary key(col) 4YKb~1qkk
8、说明:创建索引:create [unique] index idxname on tabname(col....) *b> ~L
删除索引:drop index idxname . uhP(
注:索引是不可更改的,想更改必须删除重新建。 [z?<'Tj
9、说明:创建视图:create view viewname as select statement I(C_}I>Wb
删除视图:drop view viewname :}Z+K*%o-
10、说明:几个简单的基本的sql语句 hse$M\5
选择:select * from table1 where 范围 Nl1&na)K}
插入:insert into table1(field1,field2) values(value1,value2) !bQ5CB
删除:delete from table1 where 范围 )jnxR${M
更新:update table1 set field1=value1 where 范围 n]|[|Rf1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! aaLT%
排序:select * from table1 order by field1,field2 [desc] 9= :!XkT.
总数:select count as totalcount from table1 a6[bF
求和:select sum(field1) as sumvalue from table1 6%:N^B=%}
平均:select avg(field1) as avgvalue from table1 ^"l4
最大:select max(field1) as maxvalue from table1 Zx3m$.8
最小:select min(field1) as minvalue from table1 8USF;k
Qd$d*mwg:
gVA$P
XmLHZ,/
11、说明:几个高级查询运算词 Tf` ~=fg%
qL(Qmgd
kZfO`BVL
A: UNION 运算符 \!`*F:7]-
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。 L[D}pL=
B: EXCEPT 运算符 hV_0f_Og
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。 wuI+$?
C: INTERSECT 运算符 ._#|h5
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 [@Y?'={qE
注:使用运算词的几个查询结果行必须是一致的。 {R\ "x|
12、说明:使用外连接 O]`CSTv'_
A、left outer join: AfyEFnY
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 0Bb amU
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .Q4EmpByCg
B:right outer join: dYW19$W
n
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。 klv ]+F&[
C:full outer join: @32JMS<
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。 hK?uGt
d?
Za5*HCo
]hc.cj`\W&
二、提升 5)nm6sf
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) MYDAS-
法一:select * into b from a where 1<>1 %
?@PlQ
法二:select top 0 * into b from a aOETms w
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) !Hxx6/
insert into b(a, b, c) select d,e,f from b; v~9PS2
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) ^dld\t:tV7
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Syo1Dq6z.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. |s+y]3-_
4、说明:子查询(表名1:a 表名2:b) YOy/'Le^:
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) hVd%
jU:
5、说明:显示文章、提交人和最后回复时间 fMy7pXa_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8N'[)Jw
6、说明:外连接查询(表名1:a 表名2:b) 0PjWfM8%
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c = ;4cDmZh
7、说明:在线视图查询(表名1:a ) ]`b/_LJN$F
select * from (SELECT a,b,c FROM a) T where t.a > 1; UzWf_r
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 k7'_
select * from table1 where time between time1 and time2 Lp.,:z7
select a,b,c, from table1 where a not between 数值1 and 数值2 /z.Y<xOc
9、说明:in 的使用方法 nZ0-
Kb
select * from table1 where a [not] in ('值1','值2','值4','值6') ia?{]!7$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o+r?N5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) VE`5bD+%e
11、说明:四表联查问题: An{`'U(l
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 ..... 79^Y^.D
12、说明:日程安排提前五分钟提醒 TmxhP
nJ~
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 tt$DWmm
13、说明:一条sql 语句搞定数据库分页 40w,:$
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 v[E*K@6f
14、说明:前10条记录 m0DD|7}+
select top 10 * form table1 where 范围 <%Zg;]2H`
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.) n6Je5fE
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ph
qx<N@
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 dDK4I3a
(select a from tableA ) except (select a from tableB) except (select a from tableC) }6*+>?
17、说明:随机取出10条数据 7o_1PwKS6
select top 10 * from tablename order by newid() q$L=G
18、说明:随机选择记录 &mXJL3iN
select newid() WhQK3hnm
19、说明:删除重复记录 hd0d
gc
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ND $m|V-C
20、说明:列出数据库里所有的表名 @~,&E*X! .
select name from sysobjects where type='U' ek\8u`GC
21、说明:列出表里的所有的 094~ s
select name from syscolumns where id=object_id('TableName') jeXP|;#Una
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 )WuU?Tn&
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type t.Q}V5t{g
显示结果: ur7sf$
type vender pcs 5tfD*j n
电脑 A 1 50kjX}
电脑 A 1 N1/)Fk-z
光盘 B 2 q#s:2#=
光盘 A 2 cetHpU,
手机 B 3 69/aP=
手机 C 3 Kcf1$`F24
23、说明:初始化表table1 Qf|x]x*5
TRUNCATE TABLE table1 PIOG|E
24、说明:选择从10到15的记录 r:;nv D
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Jy<hTd*q
kd55y
m03D+@F
Uao8#<CkvJ
三、技巧 3kqO5+,C
1、1=1,1=2的使用,在SQL语句组合时用的较多 T1$=0VSEa+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W;L<zFFbU)
如: '^mCLfo0}
if @strWhere !='' T<XGG_NOl
begin ^V6cx2M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ?|,dHqh{nM
end 4gD;X NrV
else 0ndk=V
begin ={g.Fn(_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l$_q#Kd
end n$Nb,/o
我们可以直接写成 2-G6I92d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C?dQ
QB$
2、收缩数据库 AUk-[i
--重建索引 B8Vhl:p
DBCC REINDEX X 8/9x-E_
DBCC INDEXDEFRAG @kh:o\
--收缩数据和日志 ~t=73fwB
DBCC SHRINKDB oz8z%*9(
DBCC SHRINKFILE ^lvYj
E
3、压缩数据库 ?58,Ja
dbcc shrinkdatabase(dbname) &JUHm_wd&S
4、转移数据库给新用户以已存在用户权限 V8KdY=[
exec sp_change_users_login 'update_one','newname','oldname' {4]sJT
go o,NTIh
5、检查备份集 7=3'PfS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b?^CnMO
6、修复数据库 =`st1K
ALTER DATABASE [dvbbs] SET SINGLE_USER
eeMeV>
GO )70i/%}7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WMi$ATq
GO U3t$h
ALTER DATABASE [dvbbs] SET MULTI_USER s2Rg-:7
GO {u}d`%_.M
7、日志清除 3*(w=;y
SET NOCOUNT ON n=F|bW
DECLARE @LogicalFileName sysname, B+VD53 V
@MaxMinutes INT, D`9 a"o
@NewSize INT HpKF7oJ'N
USE tablename -- 要操作的数据库名 B0+r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ztEM>xsk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [z[<onFIq
@NewSize = 1 -- 你想设定的日志文件的大小(M) ~fF_]UVq3
-- Setup / initialize "L9yG:
DECLARE @OriginalSize int [`n)2}
k
SELECT @OriginalSize = size vk><S|[n
FROM sysfiles uN;]Fv@Z
WHERE name = @LogicalFileName "/kTEp
SELECT 'Original Size of ' + db_name() + ' LOG is ' + b#
|
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sx^0*h-Qq
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (5/>arDn
FROM sysfiles 3;%dn\
D
WHERE name = @LogicalFileName a%YohfsY?U
CREATE TABLE DummyTrans Wm^RfxgN/
(DummyColumn char (8000) not null) BcaX:C?f
DECLARE @Counter INT, o%SD\zk
@StartTime DATETIME, AZH=r S`
@TruncLog VARCHAR(255) c'}dsq\
SELECT @StartTime = GETDATE(), qP5'&!s&!
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' o+0x1Ct3P
DBCC SHRINKFILE (@LogicalFileName, @NewSize) A(@VjXl
EXEC (@TruncLog) "6t#
-- Wrap the log if necessary. ;RzbPlkl
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired dWi:V7t+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) AuIg=-xR
AND (@OriginalSize * 8 /1024) > @NewSize 1yd}F`{8UF
BEGIN -- Outer loop. /H'F4->
SELECT @Counter = 0 !(i}FFn{:
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) efrVF5,y?
BEGIN -- update zDohp 5,
INSERT DummyTrans VALUES ('Fill Log') <|>7?#s2=
DELETE DummyTrans 2A(?9
R9&h
SELECT @Counter = @Counter + 1 + t7n6
END MO-7yp:K
EXEC (@TruncLog) MO%kUq|pg
END ?}ly`Js
SELECT 'Final Size of ' + db_name() + ' LOG is ' + P*:9u>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nXJG4$G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |kc#=b@l
FROM sysfiles 5Z_ 7Sc
WHERE name = @LogicalFileName xcM*D3
DROP TABLE DummyTrans Ftw;T|
SET NOCOUNT OFF \'hZm%S
8、说明:更改某个表 [4
y7tjar^
exec sp_changeobjectowner 'tablename','dbo' .H#<yPty
9、存储更改全部表 kNk$[Yfs
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Ka/ *Z4"
@OldOwner as NVARCHAR(128), :lE_hY
@NewOwner as NVARCHAR(128) <,+nS%a
AS TjY-C m
DECLARE @Name as NVARCHAR(128) tl"?AQcBR
DECLARE @Owner as NVARCHAR(128) <HB@j}qi
DECLARE @OwnerName as NVARCHAR(128) ,GUOq!z
DECLARE curObject CURSOR FOR R5& R~1N
select 'Name' = name, G7NRpr
'Owner' = user_name(uid) nh]}KFO h
from sysobjects *Y`c.n"
where user_name(uid)=@OldOwner $_f"NE}
order by name ><wYk)0E
OPEN curObject _?oofE:{
FETCH NEXT FROM curObject INTO @Name, @Owner 9/#?]LJ
WHILE(@@FETCH_STATUS=0) gZ@z}CIw'
BEGIN ?rxq//S2
if @Owner=@OldOwner +)ba9bJ|
begin k9m9IE"9=$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +x]3 -s
exec sp_changeobjectowner @OwnerName, @NewOwner ~-f"&@){,
end <?FkwW\?
-- select @name,@NewOwner,@OldOwner ~UNK[
FETCH NEXT FROM curObject INTO @Name, @Owner G$A=T u~
END y8j6ttQv=t
close curObject }l7@:ezZZ7
deallocate curObject EE5mVC&
GO 2y5d
10、SQL SERVER中直接循环写入数据 m[DCA\Mo@
declare @i int N4)ZPLV
set @i=1 sc&u NfJ
while @i<30 g\]~H%2 ,
begin "cz'|z`
insert into test (userid) values(@i) K_ Od u^
set @i=@i+1 N|e#&
end '!<gPAVTzV
小记存储过程中经常用到的本周,本月,本年函数 3|(<]@
$
Dateadd(wk,datediff(wk,0,getdate()),-1) '.{_
7U
Dateadd(wk,datediff(wk,0,getdate()),6) Q!y%N&
Dateadd(mm,datediff(mm,0,getdate()),0) RXRoMg!-P
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 5tl($j
Dateadd(yy,datediff(yy,0,getdate()),0) Y/ I32@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) X/ lmj_v
上面的SQL代码只是一个时间段
yT-qT_.
Dateadd(wk,datediff(wk,0,getdate()),-1) 6aKfcvf &
Dateadd(wk,datediff(wk,0,getdate()),6) dJ{q}U
就是表示本周时间段. Z;y(D_;_
下面的SQL的条件部分,就是查询时间段在本周范围内的: =Q*x=}NH
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) PiN^/#D
而在存储过程中 *WfQi8
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 8d7 NESYl
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \V#fl