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。 iRlZWgj4^
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一、基础 seBmhe5qR
1、说明:创建数据库
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CREATE DATABASE database-name $/IFSB9
2、说明:删除数据库 +,LWyvc'
drop database dbname tO:JB&vO2
3、说明:备份sql server vszm9Qf
--- 创建 备份数据的 device HdB>CVuh
USE master KU9FHN
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' }YFM40H
--- 开始 备份 Mh5>
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BACKUP DATABASE pubs TO testBack m}s.a.x
4、说明:创建新表 4^bt~{}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) igk<]AwxS
根据已有的表创建新表: C)EP;5k'!\
A:create table tab_new like tab_old (使用旧表创建新表) It&CM,=t
B:create table tab_new as select col1,col2... from tab_old definition only rlY0UA,
5、说明:删除新表 >L2_k'uE+;
drop table tabname SM4`Hys;p
6、说明:增加一个列 m x |V)
Alter table tabname add column col type ;..z)OP_
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。 b(;u2 8
7、说明:添加主键: Alter table tabname add primary key(col) 1*dN. v:5
说明:删除主键: Alter table tabname drop primary key(col) c:7F
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8、说明:创建索引:create [unique] index idxname on tabname(col....) 2*z~'i
删除索引:drop index idxname ka\{?:r,8
注:索引是不可更改的,想更改必须删除重新建。 W3/bM>1
9、说明:创建视图:create view viewname as select statement $KGMAg/H
删除视图:drop view viewname !uW*~u
10、说明:几个简单的基本的sql语句 *S:~U
选择:select * from table1 where 范围 |y eQz
插入:insert into table1(field1,field2) values(value1,value2) 0h*Le
删除:delete from table1 where 范围 6` TwP\!$/
更新:update table1 set field1=value1 where 范围 J*$%d1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $$1t4=Pz
排序:select * from table1 order by field1,field2 [desc] "}*D,[C5e
总数:select count as totalcount from table1 |;wc8;
求和:select sum(field1) as sumvalue from table1 gI;"P kN
平均:select avg(field1) as avgvalue from table1 )c' 45bD
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 ^?+[yvq
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11、说明:几个高级查询运算词 '%[ Y
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A: UNION 运算符 C:t>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。 #[{{&sN
B: EXCEPT 运算符 &3Zb?
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。 rBTg"^jsw
C: INTERSECT 运算符 X_o#!
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。 iv *$!\Cd
注:使用运算词的几个查询结果行必须是一致的。 xBTx`+%WS
12、说明:使用外连接 D`a6D
A、left outer join: Y|fD)zG_
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )0exGx+:
B:right outer join: WT<}3(S'?
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 v-3VzAd=*&
C:full outer join: K_)~&Cu*'
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Yjc U2S"=P
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二、提升 ;kk[x8$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) & mO n]
法一:select * into b from a where 1<>1 b},2A'X
法二:select top 0 * into b from a G^k'sgy.
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 5+M,X kg
insert into b(a, b, c) select d,e,f from b; `5?0yXK
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) L?d?O
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }h45j84)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <WZ{<'ajI
4、说明:子查询(表名1:a 表名2:b) ?Te#lp;`~
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) u_^mN9h
5、说明:显示文章、提交人和最后回复时间 IRm}?hHf
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b <@;}q^`
6、说明:外连接查询(表名1:a 表名2:b) \(i'i C
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l[$GOLeS
7、说明:在线视图查询(表名1:a ) lfHN_fE>Mq
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7s?#y=M
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 7! >0
select * from table1 where time between time1 and time2 FAdTm#tgW]
select a,b,c, from table1 where a not between 数值1 and 数值2 . fja;aG
9、说明:in 的使用方法 &S{r;N5u
select * from table1 where a [not] in ('值1','值2','值4','值6')
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 FprdP*/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]{6/6jl
11、说明:四表联查问题: 6~%><C
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 ..... ?;CIS$$r
12、说明:日程安排提前五分钟提醒 R QQ'Wg
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 'cpm 4mT
13、说明:一条sql 语句搞定数据库分页 &>Ve4!i
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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 I2$DlEke
14、说明:前10条记录 \
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select top 10 * form table1 where 范围 K`Kv .4
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) W:RjWn @<
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2~$S @c
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 ),p0V
(select a from tableA ) except (select a from tableB) except (select a from tableC) j J{F0o
17、说明:随机取出10条数据 LRu,_2"
select top 10 * from tablename order by newid() rH`\UZ{cc
18、说明:随机选择记录 !~vK[G(R
select newid()
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19、说明:删除重复记录 P!+Gwm{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !YAX.e
20、说明:列出数据库里所有的表名 k5Cy/gR
select name from sysobjects where type='U' -4Hb]#*2
21、说明:列出表里的所有的 Q0R05*
select name from syscolumns where id=object_id('TableName') MWv@]P_0p!
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。 a
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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 -13}]Gls7Q
显示结果: ev;&n@k_I
type vender pcs )\Q(=:
电脑 A 1 Pb'(Y
电脑 A 1 'z8FU~oU
光盘 B 2 ck{S
光盘 A 2 }?,?2U,8:
手机 B 3 Q^f{H.
手机 C 3 ^5E9p@d"J
23、说明:初始化表table1 N4+Cg t(
TRUNCATE TABLE table1 (SRY(q
24、说明:选择从10到15的记录 ~6i'V?>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc g9" wX?*
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三、技巧 !ddyJJ^a
1、1=1,1=2的使用,在SQL语句组合时用的较多 * |,N/e
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ^yPZ$Q
如: !{^kH;*u
if @strWhere !='' VBL4cU8D
begin H\QkU`b
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Wz'!stcp
end @G2# Z
else zE/l
begin r"2lcNE
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X=#us7W}
end pZ>yBY?R8>
我们可以直接写成 [o<hQ`&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v>wN
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2、收缩数据库 q|<B9Jk
--重建索引 !vf:mMo
DBCC REINDEX 8+[Vo_]
DBCC INDEXDEFRAG PN 93.G(W
--收缩数据和日志 vQ*[tp#qU
DBCC SHRINKDB 0fewMS*
DBCC SHRINKFILE I #1~CbR
3、压缩数据库 i1uoYb?4(I
dbcc shrinkdatabase(dbname) ni2#20L
4、转移数据库给新用户以已存在用户权限 ~".@mubt1$
exec sp_change_users_login 'update_one','newname','oldname' I.3~ctzu
go V,rc&97
5、检查备份集 9PKXQp
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %FYhq:j
6、修复数据库 5\pS8<RJ;
ALTER DATABASE [dvbbs] SET SINGLE_USER 7_2D4CI
GO sg7h&<Xx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK CnB[ImMs(A
GO h}@wPP{
ALTER DATABASE [dvbbs] SET MULTI_USER 3FR(gr$X
GO SQ,-45@W
7、日志清除 -kk7y
SET NOCOUNT ON j_2g*lQ7a
DECLARE @LogicalFileName sysname, T MMKRC1<
@MaxMinutes INT, !=:>y WQ
@NewSize INT P#hRqETw
USE tablename -- 要操作的数据库名 h]s6)tII
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 XA!a^@<H
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 3l?|+sU>O
@NewSize = 1 -- 你想设定的日志文件的大小(M) M
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-- Setup / initialize SvSO?H!-
DECLARE @OriginalSize int o08g]a
SELECT @OriginalSize = size zTcz+3x
FROM sysfiles veq3t$sj
WHERE name = @LogicalFileName A8&@Vxdz
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ! :]_-DX
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #$BFTlm|
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' }eVDe(7_
FROM sysfiles 72Bc0Wg
WHERE name = @LogicalFileName et+lL"&
CREATE TABLE DummyTrans B9NUafK=
(DummyColumn char (8000) not null) VF2,(f-*
DECLARE @Counter INT, IRQtA
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@StartTime DATETIME, i) e6U(H
@TruncLog VARCHAR(255) FXBmatBck
SELECT @StartTime = GETDATE(), "v:k5a(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (O J/u)W^
DBCC SHRINKFILE (@LogicalFileName, @NewSize) zU!{_Ao9
EXEC (@TruncLog) J`5+Zngr
-- Wrap the log if necessary. bpBn3f`?*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +=J$:/&U
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "]=OR>
AND (@OriginalSize * 8 /1024) > @NewSize 73X*|g[O
BEGIN -- Outer loop. ^}~Q(ji7
SELECT @Counter = 0 hOB<6Tm[
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) n'mrLZw
BEGIN -- update Hes!uy
INSERT DummyTrans VALUES ('Fill Log') o>M^&)Xs
DELETE DummyTrans my A;Y
SELECT @Counter = @Counter + 1 e^eJ!~0
END t}R!i-D|HB
EXEC (@TruncLog) xH2'PEjFM
END r7W.}n*
SELECT 'Final Size of ' + db_name() + ' LOG is ' + R7Qj<,
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~}b0zL
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [ojL9.6
FROM sysfiles c(=>5
WHERE name = @LogicalFileName =7+%31
DROP TABLE DummyTrans KuwhA-IL
SET NOCOUNT OFF :-d#kU
8、说明:更改某个表 *}C%z(
exec sp_changeobjectowner 'tablename','dbo' 01@WU1IN
9、存储更改全部表 p?$N[-W 6-
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch YWn""8p;P
@OldOwner as NVARCHAR(128), >!1]G"U
@NewOwner as NVARCHAR(128) s;bGg
AS MPUyu(-%{
DECLARE @Name as NVARCHAR(128) enPtW
DECLARE @Owner as NVARCHAR(128) !LH;K
DECLARE @OwnerName as NVARCHAR(128) ^4`x:6m
DECLARE curObject CURSOR FOR p'LLzc##
select 'Name' = name, E}4{{{r
'Owner' = user_name(uid) 9mHCms
from sysobjects lknj/i5L
where user_name(uid)=@OldOwner %BC%fVdP
order by name E?+~S M1~
OPEN curObject a&G{3#l
FETCH NEXT FROM curObject INTO @Name, @Owner N>3{!K>/Y:
WHILE(@@FETCH_STATUS=0) OF<:BaRs/
BEGIN d"n>Q Tn\
if @Owner=@OldOwner PV,Z@qm@^
begin PFpFqJ)Cs"
set @OwnerName = @OldOwner + '.' + rtrim(@Name) BaIpX<$T
exec sp_changeobjectowner @OwnerName, @NewOwner nq?+b >//
end RTVU3fw
-- select @name,@NewOwner,@OldOwner SHYekX
FETCH NEXT FROM curObject INTO @Name, @Owner g"n>v
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END 0Lj;t/mG
close curObject 9)+!*(D
deallocate curObject ^
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GO iWeUsS%zpV
10、SQL SERVER中直接循环写入数据 5)f 'wVe
declare @i int 10zM8<bl
set @i=1 x3Cn:F
while @i<30 UZt3Ua&J
begin &c-V
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insert into test (userid) values(@i) vVtkB$]L
set @i=@i+1 CX/[L)|Ru
end b(N+_=
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小记存储过程中经常用到的本周,本月,本年函数 ;sA
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Dateadd(wk,datediff(wk,0,getdate()),-1) Bs0~P 4^
Dateadd(wk,datediff(wk,0,getdate()),6) i +@avoW
Dateadd(mm,datediff(mm,0,getdate()),0) aW:*!d#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >AV9 K
Dateadd(yy,datediff(yy,0,getdate()),0) x=>dmi3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) O=U,x-Wl
上面的SQL代码只是一个时间段 ds(X[7XGW
Dateadd(wk,datediff(wk,0,getdate()),-1) LiHJm-
Dateadd(wk,datediff(wk,0,getdate()),6) <P1nfH
就是表示本周时间段. R5b,/>^'A
下面的SQL的条件部分,就是查询时间段在本周范围内的: MMjewGxe
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ):G+*3yb
而在存储过程中 +>1Yp"> ?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) x3'ANw6E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2Ax(q&`9