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。 a9;KS>~bq
l!XCYg@67
L3HC-
一、基础 y+k^CT/u
1、说明:创建数据库 P<Bx1H-z-
CREATE DATABASE database-name O>+=cg
2、说明:删除数据库 UFT JobU
drop database dbname fQC{LcS
3、说明:备份sql server awo'#Y2>
--- 创建 备份数据的 device *<S>PbqLw
USE master , @UOj=
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' nK03x YA
--- 开始 备份 smfI+Z S"
BACKUP DATABASE pubs TO testBack Nc(CGl:
4、说明:创建新表 mST8+R@S
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Lhp&RGy
根据已有的表创建新表: [u!n=ev
A:create table tab_new like tab_old (使用旧表创建新表) ?2#'>B
B:create table tab_new as select col1,col2... from tab_old definition only y>w;'QR&a
5、说明:删除新表 &~+QPnI>Pm
drop table tabname Z@dVK`nD
6、说明:增加一个列 \8$~ i
Alter table tabname add column col type j24 3oD
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 mrRid}2
7、说明:添加主键: Alter table tabname add primary key(col) izcaWt3 a
说明:删除主键: Alter table tabname drop primary key(col) XX/s@C
8、说明:创建索引:create [unique] index idxname on tabname(col....) 17?YN<
删除索引:drop index idxname UJh;Hp:
注:索引是不可更改的,想更改必须删除重新建。 BVeMV4
9、说明:创建视图:create view viewname as select statement `dcz9 *
删除视图:drop view viewname }R16WY_'
10、说明:几个简单的基本的sql语句 ;6``t+]q
选择:select * from table1 where 范围 /;(ji?wN
插入:insert into table1(field1,field2) values(value1,value2) Ur]$@N
删除:delete from table1 where 范围 #0T/^ #
更新:update table1 set field1=value1 where 范围 FHU6o910
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 'I/_vqp@
排序:select * from table1 order by field1,field2 [desc] [5~mP`He
总数:select count as totalcount from table1 ";=!PL
求和:select sum(field1) as sumvalue from table1 b9X*2pnWJ
平均:select avg(field1) as avgvalue from table1 04dz?`HuB
最大:select max(field1) as maxvalue from table1 >nSt<e
最小:select min(field1) as minvalue from table1 +Mijio
ou-UR5
I[k"I(
:!g|pd[{ag
11、说明:几个高级查询运算词 v
=y
2
R`c[?U
DNq(\@x[!
A: UNION 运算符 k o[w#j
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。 u*Xp%vNe
B: EXCEPT 运算符 &
V>rq'~;
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。 Gqd|F>
C: INTERSECT 运算符 (&eF E ;c
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。 t}_ #N'`
注:使用运算词的几个查询结果行必须是一致的。 Godrz*"
12、说明:使用外连接 =W3
K6w
A、left outer join: Dj96t5R
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。 ) %Fwfb
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 LE<J<~2Z
B:right outer join: ?< b{
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。 L>~Tc
C:full outer join: .+ u
b\
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。 7?R600OA
JXJ+lZmsz
u|t l@_
二、提升 :+Ukwno?/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1V1I[CxlX
法一:select * into b from a where 1<>1 70 7( LG
法二:select top 0 * into b from a
Qh&Qsyo%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _|GbU1Hz
insert into b(a, b, c) select d,e,f from b; [-$
Do
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) WuUwd#e
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Su,:f_If,
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !-7n69:G
4、说明:子查询(表名1:a 表名2:b) iWD|F-
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) 4l
ZK@3
5、说明:显示文章、提交人和最后回复时间 0i_:J
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b klJ21j0Bb2
6、说明:外连接查询(表名1:a 表名2:b) rT[qh+KWe
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ia'z9
7、说明:在线视图查询(表名1:a ) Q"qI'*Kgt
select * from (SELECT a,b,c FROM a) T where t.a > 1; viAAb
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 l{Df{1b.
select * from table1 where time between time1 and time2 L_!ShE
select a,b,c, from table1 where a not between 数值1 and 数值2 oVy{~D=
9、说明:in 的使用方法 O<cP1TF
select * from table1 where a [not] in ('值1','值2','值4','值6') ;`#R9\C=h
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ;Z{D@g+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ElQ?|HsQ6p
11、说明:四表联查问题: t6nRg
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 ..... P'U2hCif
12、说明:日程安排提前五分钟提醒 @ye!? %
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %BGg?&
13、说明:一条sql 语句搞定数据库分页 D8Fi{?A#FV
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 d{4;qM#
14、说明:前10条记录 GHGyeqNM
select top 10 * form table1 where 范围 [oTe8^@[
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.) !G;u
)7'v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {o24A:M
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 ^-Od*DTL
(select a from tableA ) except (select a from tableB) except (select a from tableC) qazA,|L!
17、说明:随机取出10条数据 +\Vm t[v
select top 10 * from tablename order by newid() RHC ZP
18、说明:随机选择记录 3{3@>8{w
select newid() {Uw
0zC
19、说明:删除重复记录 [Iks8ZWr_
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "OjAhKfG
20、说明:列出数据库里所有的表名 *XTd9E^tXq
select name from sysobjects where type='U' tVn?cS
21、说明:列出表里的所有的 |EE1S{!24m
select name from syscolumns where id=object_id('TableName') 6^Wep- $
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。 &|>~7(
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 GF ux?8A:%
显示结果: _!',%+
type vender pcs YqX$a~
电脑 A 1 4 ThFC
电脑 A 1 /IpCo
光盘 B 2 ;>?h/tS6
光盘 A 2 Ki;SONSV~|
手机 B 3 -x//@8"
手机 C 3 /WTEz\k
23、说明:初始化表table1 ss)x
fG
TRUNCATE TABLE table1 f4f2xe7\Q
24、说明:选择从10到15的记录 ~18a&T:
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc q?(]
Y*
Y b+A{`
@z@%vr=vX
D!&(#Vl
_
三、技巧 y+(\:;y$7
1、1=1,1=2的使用,在SQL语句组合时用的较多 k]@]a
"where 1=1" 是表示选择全部 "where 1=2"全部不选, A;TP~xq\
如: Nwi|>'\C
if @strWhere !='' [r/zBF-.
begin &P?2H66s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere j<<d A[X
end FO2e7p^Q
else PE%$g\#?
begin 1)(>'pY
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -* ,CMw
end !ZBtXt#P
我们可以直接写成 @[n#-!i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rpT.n-H>%A
2、收缩数据库 L80(9Y^xn
--重建索引 'h*jL@%TT
DBCC REINDEX p>B2bv+L
DBCC INDEXDEFRAG 8 t5kou]h
--收缩数据和日志 t7+A!7b{
DBCC SHRINKDB EA& 3rI>U)
DBCC SHRINKFILE xl\Kj2^
3、压缩数据库 $m 4-^=
dbcc shrinkdatabase(dbname) Jxe+LG
4、转移数据库给新用户以已存在用户权限 ~K;QdV=YX
exec sp_change_users_login 'update_one','newname','oldname' ":Dm/g
go tq3_az ~1
5、检查备份集 ;m(iKwDt
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' sl]<A[jR
6、修复数据库 8-2`S*
ALTER DATABASE [dvbbs] SET SINGLE_USER 4_R|3L
GO w_(3{P[Iz
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x|6]+?l@6
GO -R`{]7V
ALTER DATABASE [dvbbs] SET MULTI_USER <g[z jV9p
GO %nZl`<M
7、日志清除 Z?axrGmg0
SET NOCOUNT ON hS]w
A"\87
DECLARE @LogicalFileName sysname, vi,hWz8WB
@MaxMinutes INT, Y?0/f[Ax,y
@NewSize INT ~e{ @ 5.g
USE tablename -- 要操作的数据库名 1 R5pf
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ZwmucY%3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -#|D>
@NewSize = 1 -- 你想设定的日志文件的大小(M) NQ9v[gv
-- Setup / initialize kka5=u
DECLARE @OriginalSize int ;5Sdx5`_
SELECT @OriginalSize = size @]=40Yj~w
FROM sysfiles WgtLKRZ\
WHERE name = @LogicalFileName L|=5jn9 :
SELECT 'Original Size of ' + db_name() + ' LOG is ' + jJ,_-ui
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0t <nH%N}^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $83B10OQ&L
FROM sysfiles '/W$9jm
WHERE name = @LogicalFileName )[Y B&
CREATE TABLE DummyTrans mayJwBfU
(DummyColumn char (8000) not null) c3vb~l)
DECLARE @Counter INT,
cw Obq\
@StartTime DATETIME, aB]0?C y9(
@TruncLog VARCHAR(255) 4DA34m(
SELECT @StartTime = GETDATE(), ~^mUu`@r
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [{x}# oRSE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) pCIzpEsRs
EXEC (@TruncLog) %$!3Pbui
-- Wrap the log if necessary. ag=d6q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Rr)+M3'
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Jz@~$L
AND (@OriginalSize * 8 /1024) > @NewSize ?8b19DMK6
BEGIN -- Outer loop. lPTx] =G
SELECT @Counter = 0 yeo&Qz2vU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) P?54"$b
BEGIN -- update c`a(
INSERT DummyTrans VALUES ('Fill Log') G.W !
DELETE DummyTrans 8t-GsjHb
SELECT @Counter = @Counter + 1 drq3=2
END ]R__$fl`8
EXEC (@TruncLog) kx"10Vw
END +&EXTZ@o
SELECT 'Final Size of ' + db_name() + ' LOG is ' + FfoOJzf~o
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + gAqK)@8-
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ;XKe$fsa~?
FROM sysfiles *ukyQZ9
WHERE name = @LogicalFileName 6
63o
DROP TABLE DummyTrans %oZ:Awx
SET NOCOUNT OFF J$dwy$n
8、说明:更改某个表 kxn&f(5
exec sp_changeobjectowner 'tablename','dbo' }Mcb\+[
9、存储更改全部表 }r:o8+4
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %`Re{%1;
@OldOwner as NVARCHAR(128), 4fEDg{T
@NewOwner as NVARCHAR(128) }cKB)N
BJb
AS pfA6?tP`
DECLARE @Name as NVARCHAR(128) zkQ[<
DECLARE @Owner as NVARCHAR(128) +X}i%F'
DECLARE @OwnerName as NVARCHAR(128) "t@p9>
DECLARE curObject CURSOR FOR #/)t]&n
select 'Name' = name, C8N)!5(A
'Owner' = user_name(uid) r"h;JC/&<T
from sysobjects i|YS>Pw~j
where user_name(uid)=@OldOwner mgs(n5V5
order by name a?cJl
OPEN curObject s{hKl0ds
FETCH NEXT FROM curObject INTO @Name, @Owner UO/sv2CN
WHILE(@@FETCH_STATUS=0) :+rGBkw1m
BEGIN N##`
if @Owner=@OldOwner _73q,3`24
begin .g*j]!_]
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 7N.b-}$(
exec sp_changeobjectowner @OwnerName, @NewOwner MK$u}G
end 'M90Yia
-- select @name,@NewOwner,@OldOwner sp9gz~Kq
FETCH NEXT FROM curObject INTO @Name, @Owner QLA.;`HIE
END bz>X~
close curObject cr7MvXF-
deallocate curObject $vO&C6m$
GO O] _4pP
10、SQL SERVER中直接循环写入数据 7nZPh3%
declare @i int e#eVc'=cDR
set @i=1 C0rf
while @i<30 !40>LpL[
begin /zn=AAYb
insert into test (userid) values(@i) d[ N1zQW
set @i=@i+1 ~%TWF+
end gEA SYIQ
小记存储过程中经常用到的本周,本月,本年函数 \bA Yic
Dateadd(wk,datediff(wk,0,getdate()),-1) Z:;}
Dateadd(wk,datediff(wk,0,getdate()),6) 9>""xt
Dateadd(mm,datediff(mm,0,getdate()),0) R%E7 |NAG
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) bS.w<V
Ew
Dateadd(yy,datediff(yy,0,getdate()),0) ]S|FK>U[
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) niVR!l
上面的SQL代码只是一个时间段 wb-yAQ8
Dateadd(wk,datediff(wk,0,getdate()),-1) 7*/{m K)
Dateadd(wk,datediff(wk,0,getdate()),6) 5=dL`
就是表示本周时间段. I<SgKva;c
下面的SQL的条件部分,就是查询时间段在本周范围内的: k$EVr([
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) K|& f5w
而在存储过程中 Z 6jEj9?O
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Mf}M/Fh
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) wBPo{