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。 p-GT`D
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一、基础 # nfI%
1、说明:创建数据库 7SI)1_%G
CREATE DATABASE database-name ke/_k/
2、说明:删除数据库 W'_/6_c$!
drop database dbname r@T| e
3、说明:备份sql server EaS~`
--- 创建 备份数据的 device S=gW(c2'
USE master 2w?G.pO#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' dmR3Y.\jd
--- 开始 备份 ]
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BACKUP DATABASE pubs TO testBack SZVV40w
4、说明:创建新表 "E*8h/4u
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }sMW3'V
根据已有的表创建新表: i#,1iVSG
A:create table tab_new like tab_old (使用旧表创建新表) Q2C)tVK+
B:create table tab_new as select col1,col2... from tab_old definition only /BH.>R4`A
5、说明:删除新表 "+iAd.qd
drop table tabname {Iy7.c8S
6、说明:增加一个列 ^i<}]c_|f
Alter table tabname add column col type ;mO,3dV
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。 L(WOet( '
7、说明:添加主键: Alter table tabname add primary key(col) _g6m=N4
说明:删除主键: Alter table tabname drop primary key(col) Sb^
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8、说明:创建索引:create [unique] index idxname on tabname(col....) A|<;
删除索引:drop index idxname |#TXE|#ux
注:索引是不可更改的,想更改必须删除重新建。 $cK^23H/Fj
9、说明:创建视图:create view viewname as select statement 7;HUE!5,^l
删除视图:drop view viewname ;.Zh,cU
10、说明:几个简单的基本的sql语句 N4 [E~-
选择:select * from table1 where 范围 :$"7-a%f
插入:insert into table1(field1,field2) values(value1,value2) R'EW7}&
删除:delete from table1 where 范围 U($^E}I2(
更新:update table1 set field1=value1 where 范围 GhnE>d;i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $P?{O3:V
排序:select * from table1 order by field1,field2 [desc] o_yRn16
总数:select count as totalcount from table1 xQz#i-v
求和:select sum(field1) as sumvalue from table1 ^now}u9S6
平均:select avg(field1) as avgvalue from table1 A9BxwQU#
最大:select max(field1) as maxvalue from table1 GqjO>v fy
最小:select min(field1) as minvalue from table1 IYNMU\s
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11、说明:几个高级查询运算词 v+tO$QZ`
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A: UNION 运算符 (G5T%[/U
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。 vug-n 8
B: EXCEPT 运算符 ~yN(-I1P
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。 ChIoR:y>
C: INTERSECT 运算符 e<'U8|}hc{
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。 *?Wtj
注:使用运算词的几个查询结果行必须是一致的。 }'jV/
12、说明:使用外连接 Kcn\g.
A、left outer join: EW5]!%
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。 v,\93mNp[
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 SY6r 8RK
B:right outer join: J%4HNW*p
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。 70<K.T<b
C:full outer join: /s-d?
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。 luF#OP C
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二、提升 --/-D5
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) &V;x 4
法一:select * into b from a where 1<>1 sUda
法二:select top 0 * into b from a xL&PJ /'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^%zNa6BL
insert into b(a, b, c) select d,e,f from b; |Y4q+sDW
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) dKe@JQ+-z
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 x=3I)}J(kn
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +GPd
4、说明:子查询(表名1:a 表名2:b) gCwt0)
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) LO>8 j:
5、说明:显示文章、提交人和最后回复时间 !>|`ly$6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b cX"G7Bh
6、说明:外连接查询(表名1:a 表名2:b) 3qcpf:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5xv,!/@
7、说明:在线视图查询(表名1:a ) Fs9W>*(
select * from (SELECT a,b,c FROM a) T where t.a > 1; #,Bj!'Q'-
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 q5gP~*?
select * from table1 where time between time1 and time2 coO.kTO;
select a,b,c, from table1 where a not between 数值1 and 数值2 ULbP_y>(Y
9、说明:in 的使用方法 #x|VfN5f
select * from table1 where a [not] in ('值1','值2','值4','值6') >;.*
10、说明:两张关联表,删除主表中已经在副表中没有的信息 MZiF];OY
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) |bvGYsn_#=
11、说明:四表联查问题: W["HDR
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where .....
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12、说明:日程安排提前五分钟提醒 HtS#_y%(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 M[vCpa
13、说明:一条sql 语句搞定数据库分页 _pW'n=}R
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 @_uFX!;
14、说明:前10条记录 }Y$VB%&Hy
select top 10 * form table1 where 范围 W#Cq6N
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.) }amE6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) *hl<Y,W(
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 =KW|#]RB^
(select a from tableA ) except (select a from tableB) except (select a from tableC) k^yy$^=<
17、说明:随机取出10条数据 tpz=}q
select top 10 * from tablename order by newid() ^X(_zinN"
18、说明:随机选择记录 [sptU3,2U
select newid() :`j"Sj!t3
19、说明:删除重复记录 s3y}Yg
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) YL!oF^XO
20、说明:列出数据库里所有的表名 *q[^Q'jnN
select name from sysobjects where type='U' 1[#
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21、说明:列出表里的所有的 tdb4?^.s
select name from syscolumns where id=object_id('TableName') fIlIH
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。 `v<f}
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 3V!W@[ }:
显示结果: @hBx,`H^
type vender pcs \ /sF:~=
电脑 A 1 ~vkud+r
电脑 A 1 2"_ 18l.
光盘 B 2 ;p .j
光盘 A 2 @]yQJuXA&Z
手机 B 3 V?o&])?[
手机 C 3 L;kyAX@^
23、说明:初始化表table1 <|wmjW/D
TRUNCATE TABLE table1 MbM:3
24、说明:选择从10到15的记录 ),z,LU Yf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc H.f9d.<W%
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三、技巧 ~'|&{-<
1、1=1,1=2的使用,在SQL语句组合时用的较多 X ^9t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jeyaT^F(
如: )
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if @strWhere !='' 8g&uE*7N
begin KS8\F0q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _GRv
end 7?*~oVZW
else wP+'04H0
begin 8HB?=a2Q<'
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]IL3 $eR
end "P9wT)J_
我们可以直接写成 xU:PhhS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :s? y,
2、收缩数据库 ((n5';|N
--重建索引
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DBCC REINDEX o(vZ*^\
DBCC INDEXDEFRAG X/K| WOO6
--收缩数据和日志 eDvXU_yA
DBCC SHRINKDB {_+>"esc
DBCC SHRINKFILE cM|af#o
3、压缩数据库 06Sqn3MB
dbcc shrinkdatabase(dbname) 2I9{+>k
4、转移数据库给新用户以已存在用户权限 3Ro7M=]
exec sp_change_users_login 'update_one','newname','oldname' #{.pQi})
go =#J9
5、检查备份集 Q2??Kp]1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <$Xn:B<H
6、修复数据库 i,\t]EJAU
ALTER DATABASE [dvbbs] SET SINGLE_USER >!CH7wX
GO )yfOrsM
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >0[qi1
GO &L2`L)
ALTER DATABASE [dvbbs] SET MULTI_USER T749@! v`z
GO v#zfs'
7、日志清除 p=je"{
SET NOCOUNT ON ?d,acm
DECLARE @LogicalFileName sysname, =W97|BIW,
@MaxMinutes INT, N$L&|4r
@NewSize INT !:`Ra
USE tablename -- 要操作的数据库名 a'(lVZA;
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 C&qDvvk
@MaxMinutes = 10, -- Limit on time allowed to wrap log. gqKC 4'G0
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1mkQ"E4
-- Setup / initialize hwG||;&/H
DECLARE @OriginalSize int 6+5(.z-[
SELECT @OriginalSize = size .T[!!z#^
FROM sysfiles u&Ie%@:h9R
WHERE name = @LogicalFileName Vz+=ZK r5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + =D;UMSf
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + C]{V%jU
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' E$oA+n~
FROM sysfiles R;N>#_9HU
WHERE name = @LogicalFileName ,(5dQ` hA0
CREATE TABLE DummyTrans as\)S?0`.
(DummyColumn char (8000) not null) 9'1;-^U1
DECLARE @Counter INT, 4
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@StartTime DATETIME, |ij W_r
@TruncLog VARCHAR(255) _r^G%Mvy|
SELECT @StartTime = GETDATE(), ]ys4
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' RJ7/I/yD|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) rmAP&Gw I
EXEC (@TruncLog) 1L(Nfkh
-- Wrap the log if necessary. cftn`:(&8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !~VR|n-
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) mDe+ M{/
AND (@OriginalSize * 8 /1024) > @NewSize Ynt&cdK9
BEGIN -- Outer loop. +$an*k9
SELECT @Counter = 0 5Od(J5`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) '8((;N|I^
BEGIN -- update }*{\)7g
INSERT DummyTrans VALUES ('Fill Log') UeC%Wa<[
DELETE DummyTrans P+D|_3j
SELECT @Counter = @Counter + 1 C'xU=OnA8
END Mf,Mcvs
EXEC (@TruncLog) h1D~AgZOVj
END z.\[Va$@l
SELECT 'Final Size of ' + db_name() + ' LOG is ' + '+GVozc6c"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <y b=!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' HtS1N}@
FROM sysfiles rVIb'sa
WHERE name = @LogicalFileName /s-jR]#VA
DROP TABLE DummyTrans cnjj)
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SET NOCOUNT OFF t8wz'[z
8、说明:更改某个表 -;DE&~p
exec sp_changeobjectowner 'tablename','dbo' "|~B};|MFF
9、存储更改全部表 EZa{C}NQ$2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y}H*p
@OldOwner as NVARCHAR(128), ?geWR_Z
@NewOwner as NVARCHAR(128) {?kKpMNNn
AS :@z5& h
DECLARE @Name as NVARCHAR(128) y("0Xve
DECLARE @Owner as NVARCHAR(128) IU;pkgBj0Y
DECLARE @OwnerName as NVARCHAR(128) t=@Jw
DECLARE curObject CURSOR FOR ?yd(er<_f
select 'Name' = name, 9_CA5?y$:
'Owner' = user_name(uid) 4<K ,w{I
from sysobjects LMhY"/hAXa
where user_name(uid)=@OldOwner j#.-MfB
order by name Duo#WtC
OPEN curObject SS<+fWXE
FETCH NEXT FROM curObject INTO @Name, @Owner v"?PhO/{=
WHILE(@@FETCH_STATUS=0) QYCNO#*
BEGIN P*qNRP%
if @Owner=@OldOwner BIB>U W
begin [laL6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) WRU@i;l
exec sp_changeobjectowner @OwnerName, @NewOwner MjF.>4
end R4J>M@-0v
-- select @name,@NewOwner,@OldOwner 86)
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FETCH NEXT FROM curObject INTO @Name, @Owner hZF&PV5H
END m@
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close curObject ]mGsNQ ].H
deallocate curObject 'c+qBSDA
GO XC8z|A-@
10、SQL SERVER中直接循环写入数据 /x"pj3
declare @i int >+c`GpZH
set @i=1 "x) pp
while @i<30 ,Elga}7u
begin \~1zAiSd>#
insert into test (userid) values(@i) KLv
set @i=@i+1 3B_} :
end 4Hd@U&E
小记存储过程中经常用到的本周,本月,本年函数 7=ga_2
Dateadd(wk,datediff(wk,0,getdate()),-1) >kLH6.
Dateadd(wk,datediff(wk,0,getdate()),6) (nZ=9+j]d
Dateadd(mm,datediff(mm,0,getdate()),0) uB)6\fkTB
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) .f!eRV.&
Dateadd(yy,datediff(yy,0,getdate()),0) )9W#5V$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) HjY-b*B
上面的SQL代码只是一个时间段 7g<`wLAH
Dateadd(wk,datediff(wk,0,getdate()),-1) DEeL48{R
Dateadd(wk,datediff(wk,0,getdate()),6) xo"4mbTV
就是表示本周时间段. 0b QiUcg/
下面的SQL的条件部分,就是查询时间段在本周范围内的: 06W=(fY
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) K]]rOF
而在存储过程中 ~ !+h"%'t
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 'C?f"P:X{
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 01d26`G$i~