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。 s^n}m#T
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一、基础
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1、说明:创建数据库 GWU"zWli]z
CREATE DATABASE database-name .-Xp]>f,
2、说明:删除数据库 *yx&4)Or
drop database dbname V*bX>D/
3、说明:备份sql server covr0N)
--- 创建 备份数据的 device LXm5f;
USE master .|pyloL.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' JFvVRGWB
--- 开始 备份 @vC7j>*4B
BACKUP DATABASE pubs TO testBack Y)-)owx7
4、说明:创建新表 J9kmIMq-C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9b/7~w.
根据已有的表创建新表: @"\j]ZEnY
A:create table tab_new like tab_old (使用旧表创建新表) Dj~]]
B:create table tab_new as select col1,col2... from tab_old definition only WI?iz-,](
5、说明:删除新表 yJheni
drop table tabname !&3iZQGWv
6、说明:增加一个列 "K"]/3`k-
Alter table tabname add column col type '>}dqp{Wr
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。 Z]1=nSv
7、说明:添加主键: Alter table tabname add primary key(col) Zj*kHjn"
说明:删除主键: Alter table tabname drop primary key(col) Ls<.&3X2
8、说明:创建索引:create [unique] index idxname on tabname(col....) <H Le,
删除索引:drop index idxname gm-I)z!tz
注:索引是不可更改的,想更改必须删除重新建。 d"1DE
9、说明:创建视图:create view viewname as select statement :`9hgd/9
删除视图:drop view viewname 3N'f Hy
10、说明:几个简单的基本的sql语句 \uumNpB*n
选择:select * from table1 where 范围 #q06K2
插入:insert into table1(field1,field2) values(value1,value2) <h$Nh0
删除:delete from table1 where 范围 Bc/'LI.%
更新:update table1 set field1=value1 where 范围 ],fu#pi=]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! fI/?2ZH
排序:select * from table1 order by field1,field2 [desc] Koi
总数:select count as totalcount from table1 uG|d7LS,%
求和:select sum(field1) as sumvalue from table1 W;Rx(o>
平均:select avg(field1) as avgvalue from table1 eYER"E
最大:select max(field1) as maxvalue from table1 m#D+Yh/y{n
最小:select min(field1) as minvalue from table1 CDy *8<-&
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11、说明:几个高级查询运算词 ~\4B 1n7
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A: UNION 运算符 !n=?H1@
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。 NhI&wl
B: EXCEPT 运算符 9 >t
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。 aUdbN&G
C: INTERSECT 运算符 YWV"I|Z
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。 j.3#rxq
注:使用运算词的几个查询结果行必须是一致的。 ; bBz<
12、说明:使用外连接 5/v,|
A、left outer join: y^rcUPLT
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。 YF+hN\
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 F-\Swbx+
B:right outer join: *h<=
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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。 *^BW[C/CTR
C:full outer join: 'IorjR@40
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。 ho1Mo
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二、提升 b8?qYm
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Qy)+YhE
法一:select * into b from a where 1<>1 p.r \|
法二:select top 0 * into b from a uHBEpqC%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +d[A'&"
insert into b(a, b, c) select d,e,f from b; p2c4 <f-M
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) wq[\Fb`
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 2Xu?/yd
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) GM.2bA(y
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) "(@W^qF}d
5、说明:显示文章、提交人和最后回复时间 y8Q96zi
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 49)A.Bh&!
6、说明:外连接查询(表名1:a 表名2:b) L53qQej<
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~s}0z&v^te
7、说明:在线视图查询(表名1:a ) *WSH-*0
select * from (SELECT a,b,c FROM a) T where t.a > 1; 'Zq$W]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 }E01B_T9z
select * from table1 where time between time1 and time2 wzw`9^B
select a,b,c, from table1 where a not between 数值1 and 数值2 OH.Re6Rr
9、说明:in 的使用方法 4Xna}7
select * from table1 where a [not] in ('值1','值2','值4','值6') u9WQ0.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 _3q%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RwH<JaL:
11、说明:四表联查问题: ?e? mg
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 ..... %ZNp
12、说明:日程安排提前五分钟提醒 /PP\L](
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n-h2SQl!
13、说明:一条sql 语句搞定数据库分页 G;:D6\
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 \z}/=Qgc
14、说明:前10条记录
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select top 10 * form table1 where 范围 ; Q-f6)+&
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.) x\=2D<@az
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) HaP0;9q
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 *>Z|!{bI
(select a from tableA ) except (select a from tableB) except (select a from tableC) r]x;JBy
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() B]PTe~n^
18、说明:随机选择记录 H'Mc]zw_,
select newid() zj!&12w%3
19、说明:删除重复记录 $#4J^(I*:
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5XO eYO{
20、说明:列出数据库里所有的表名 fvajNP
select name from sysobjects where type='U' V?g@pnN"
21、说明:列出表里的所有的 >Z#=<
select name from syscolumns where id=object_id('TableName') Wsn}Y-x
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 RP]hW{:U
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 1vcI`8%S+u
显示结果: KtWG2
type vender pcs ]w _,0q
电脑 A 1 lYlU8l5>
电脑 A 1 stnyJ9
光盘 B 2 lO/<xSjNd
光盘 A 2 =*q|568
手机 B 3 K)2ZH@
手机 C 3 {}?;|&_
23、说明:初始化表table1 @MfuV4*
TRUNCATE TABLE table1 {;(X#vK}9
24、说明:选择从10到15的记录 /Kmzi9j+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ({3hX"C@Q
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三、技巧 W_EM
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1、1=1,1=2的使用,在SQL语句组合时用的较多 C24[brf
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8?S32Gdu
如: 7@g8nv(p
if @strWhere !='' |]a=He;
begin 9Vx2VjK2'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Bcx-t)[
end D_GIj$%N[
else z`-?5-a]I
begin u,0N[.&N
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' s8| =1{
end 6JWCB9$4
我们可以直接写成 ?2VY^7N[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \oF79
2、收缩数据库 v*%#Fp,g8
--重建索引 03*` T
DBCC REINDEX VOBzB]
DBCC INDEXDEFRAG @sly-2{e1
--收缩数据和日志 #LlHsY530N
DBCC SHRINKDB }7CMXw
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DBCC SHRINKFILE \^iPU 27H
3、压缩数据库 PF@+~FI
dbcc shrinkdatabase(dbname) ._m+@Uy]H}
4、转移数据库给新用户以已存在用户权限 >{i/LC^S
exec sp_change_users_login 'update_one','newname','oldname' ;crQ7}k
go n(.y_NEgV!
5、检查备份集 ]]{$X_0n
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' U'S}7gya
6、修复数据库 ~lMw*Qw^
ALTER DATABASE [dvbbs] SET SINGLE_USER F)/}Q[o8
GO Z~{0XG\Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Zrp`91&I
GO 6_/691
ALTER DATABASE [dvbbs] SET MULTI_USER Z]l<,m
GO {hB7F"S
7、日志清除 ghm5g/
SET NOCOUNT ON y0qrl4S)v
DECLARE @LogicalFileName sysname, brJ_q0@
@MaxMinutes INT, O(;K]8
@NewSize INT hK9Trr wau
USE tablename -- 要操作的数据库名 Dt)\q^bH)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {dJC3/Rf
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !b0'd'xe
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7''l\3mIn
-- Setup / initialize kH1hsDe|&y
DECLARE @OriginalSize int ";38vjIV
SELECT @OriginalSize = size 1g6AzUXg
FROM sysfiles 9;s:Bo
WHERE name = @LogicalFileName v5l)T}Nb
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^'i(@{{o\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `;b@a<Wl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {4Y@DQ-
FROM sysfiles `O(ec
WHERE name = @LogicalFileName Tx?,]c,(u
CREATE TABLE DummyTrans X-9>;Mb~y
(DummyColumn char (8000) not null) N-|E^XIV
DECLARE @Counter INT, Etty{r}
@StartTime DATETIME, *@=in7*c
@TruncLog VARCHAR(255) Mk"+*G
SELECT @StartTime = GETDATE(), MB
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' cVJ"^wgBt
DBCC SHRINKFILE (@LogicalFileName, @NewSize) V0 x[sEW
EXEC (@TruncLog) {~>?%]tf
-- Wrap the log if necessary. +9G
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ?F20\D\V
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) aO('X3?
AND (@OriginalSize * 8 /1024) > @NewSize ZB GLwe
BEGIN -- Outer loop. Xn-GSW3{
SELECT @Counter = 0 Xu`c_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $j:$
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BEGIN -- update $u_0"sUV
INSERT DummyTrans VALUES ('Fill Log') j*>+^g\Q6
DELETE DummyTrans 3}=r.\]U
SELECT @Counter = @Counter + 1 :S}!i?n
END ~C=I{qzF+
EXEC (@TruncLog) TSqfl/UI
END .MkHB0
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + M3@Wb@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Hrq1 {3~
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' *JE%bQ2Q
FROM sysfiles Twyx(~'&R
WHERE name = @LogicalFileName R/r)l<X@
DROP TABLE DummyTrans pC
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SET NOCOUNT OFF k@U8K(:x
8、说明:更改某个表 w@Uw8b
exec sp_changeobjectowner 'tablename','dbo' LnIln[g:
9、存储更改全部表 D"0:n.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch W)3?T&`
@OldOwner as NVARCHAR(128), *LpEH,J
@NewOwner as NVARCHAR(128) >_P7 k5Y^
AS D-e0q)RSU
DECLARE @Name as NVARCHAR(128) G%w.Z< qy
DECLARE @Owner as NVARCHAR(128) )orVI5ti
DECLARE @OwnerName as NVARCHAR(128) lP& 7U
DECLARE curObject CURSOR FOR :8aa #bA
select 'Name' = name, Vy0s%k
'Owner' = user_name(uid) M*FUtu
from sysobjects P:h;"
where user_name(uid)=@OldOwner J$
order by name `<!Nk^2ap
OPEN curObject =r"8J5[f
FETCH NEXT FROM curObject INTO @Name, @Owner &C<K|F!j!
WHILE(@@FETCH_STATUS=0) cHOtMPyQ
BEGIN MTo<COp($
if @Owner=@OldOwner OJiW@Z_\
begin yQE|FbiA
set @OwnerName = @OldOwner + '.' + rtrim(@Name) eznt "Rr2
exec sp_changeobjectowner @OwnerName, @NewOwner O*{<{3
end Pe6}y
-- select @name,@NewOwner,@OldOwner \7PPFKS
FETCH NEXT FROM curObject INTO @Name, @Owner Q\Dx/?g!vx
END r!SMF]?SJ
close curObject ^Gt&c_gH
deallocate curObject u~n*P``{
GO RUqN,C,m5I
10、SQL SERVER中直接循环写入数据 i'9aQi"G
declare @i int >p#` %S
set @i=1 %jz]s4u$5j
while @i<30 0fwmQ'lW(
begin LVKvPi
insert into test (userid) values(@i) 4k/B=%l
set @i=@i+1 [xzgk[>5
end g^|}e?
小记存储过程中经常用到的本周,本月,本年函数 !.1oW(
Dateadd(wk,datediff(wk,0,getdate()),-1) ^Pl(V@
Dateadd(wk,datediff(wk,0,getdate()),6) c} )U:?6
Dateadd(mm,datediff(mm,0,getdate()),0) 3/c3e{,!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) .[&0FHnJ5
Dateadd(yy,datediff(yy,0,getdate()),0) nMXk1`|/)x
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) A>WMPe:sSS
上面的SQL代码只是一个时间段 it]im
Dateadd(wk,datediff(wk,0,getdate()),-1) }5c%v1
Dateadd(wk,datediff(wk,0,getdate()),6) m ;-FP 2~
就是表示本周时间段. h}-}!v
下面的SQL的条件部分,就是查询时间段在本周范围内的: `G*7y7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) zQ3m@x
而在存储过程中 +GCN63nX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ;6S,|rC]
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) XN9s!5A<L)