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。 ReE-I/n8f
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一、基础 ?w6zq|
1、说明:创建数据库 w@RVg*`%7D
CREATE DATABASE database-name gI8r SmH
2、说明:删除数据库 V#8]io
drop database dbname [=M0%"
3、说明:备份sql server fDyFkhc
--- 创建 备份数据的 device bl@0+NiM
USE master 59K%bz5t
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0"q_c-_Bg
--- 开始 备份 %zj;~W;qPH
BACKUP DATABASE pubs TO testBack H.`>t
4、说明:创建新表 ]-h$CJSY
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) fFP>$
根据已有的表创建新表: T \%{zz_(
A:create table tab_new like tab_old (使用旧表创建新表) s`"o-w\$>
B:create table tab_new as select col1,col2... from tab_old definition only [DrG;k ?
5、说明:删除新表 Ei!t#'*D<
drop table tabname vzD3_
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6、说明:增加一个列 Q`mw2$zv
Alter table tabname add column col type 3C'`c=
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 /3|uU
7、说明:添加主键: Alter table tabname add primary key(col) wq&|V
说明:删除主键: Alter table tabname drop primary key(col) [pMJ9
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8、说明:创建索引:create [unique] index idxname on tabname(col....) c@u)m}V
删除索引:drop index idxname `H+~LVH
注:索引是不可更改的,想更改必须删除重新建。 _22;hnG<iy
9、说明:创建视图:create view viewname as select statement me]O
删除视图:drop view viewname Z-(#}(HD
10、说明:几个简单的基本的sql语句 ,Q|[Yr
选择:select * from table1 where 范围 ]~S,K}T
插入:insert into table1(field1,field2) values(value1,value2) }p-<+sFo
删除:delete from table1 where 范围 mXZOkx{
更新:update table1 set field1=value1 where 范围 @Dc?fyY*o<
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \2cbZQx
排序:select * from table1 order by field1,field2 [desc] jP'.a. ^o$
总数:select count as totalcount from table1 wI'8B{[
求和:select sum(field1) as sumvalue from table1 xK4b(KJj
平均:select avg(field1) as avgvalue from table1 Cb}hE
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最大:select max(field1) as maxvalue from table1 , VZ;=
最小:select min(field1) as minvalue from table1 b;$ -s
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11、说明:几个高级查询运算词 BLxtS
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A: UNION 运算符 ""`>v`\
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。 e*5TZ7.
B: EXCEPT 运算符 QuFcc}{<]
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。 'G1~\CT
C: INTERSECT 运算符 nLK%5C
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。 jxA`RSY
注:使用运算词的几个查询结果行必须是一致的。 O8BxXa@5
12、说明:使用外连接 :x e/7 -
A、left outer join: $47cKit|k:
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。 \(UEjlo
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 GCx1lm
B:right outer join: Jp)>Wd
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。 n]&/?6}
C:full outer join: ow :}NI
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。 I"awvUP]a[
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二、提升 bni :B?#
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) u@d`$]/>F
法一:select * into b from a where 1<>1 vUa~PN+Iy
法二:select top 0 * into b from a 4-^LC<}k
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) g Z3VT{
insert into b(a, b, c) select d,e,f from b; /BC(O[P
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) G=4Da~<ij
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |a@$KF$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. (Bs0/C
4、说明:子查询(表名1:a 表名2:b) W]|;ZzZ=m
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) e6s-;
5、说明:显示文章、提交人和最后回复时间 :nki6Rkowt
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b <p<jXwl
6、说明:外连接查询(表名1:a 表名2:b) }>:v
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _2{i}L
7、说明:在线视图查询(表名1:a ) .S/W_R
select * from (SELECT a,b,c FROM a) T where t.a > 1; dP0!?J Y
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 #BK\cIr
select * from table1 where time between time1 and time2 6hKavzSi
select a,b,c, from table1 where a not between 数值1 and 数值2 #W<D~C[I _
9、说明:in 的使用方法 yO
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select * from table1 where a [not] in ('值1','值2','值4','值6') `X?l`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 %XGwQB$zk8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) IQ$l!)
11、说明:四表联查问题: Nx4_Oc^hY
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 ..... PN0l#[{EN
12、说明:日程安排提前五分钟提醒 N*JWd
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 WE$Pi;q1
13、说明:一条sql 语句搞定数据库分页 w?kdM1T
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Zcd!y9]#
14、说明:前10条记录 31mY]Jve"
select top 10 * form table1 where 范围 e"en
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ;zI;oY#.y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }x% ;y]S
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 L+Q"z*W
(select a from tableA ) except (select a from tableB) except (select a from tableC) +=I_3Wtth
17、说明:随机取出10条数据 u->UV:u
select top 10 * from tablename order by newid() ]D&$k P(
18、说明:随机选择记录 W&`_cGoP
select newid() k^I4z^O=-;
19、说明:删除重复记录 D6Ov]E:fa
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) mj :8ZZ
20、说明:列出数据库里所有的表名 b\~rL,7(
select name from sysobjects where type='U' qA:CV(Z
21、说明:列出表里的所有的 . (*V|&n
select name from syscolumns where id=object_id('TableName') K V^`
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。 hnS
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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 $oK,&_
显示结果: .(Q3M0.D
type vender pcs ^!H8"CdC3
电脑 A 1 pLMki=.Ld
电脑 A 1 '/
3..3k
光盘 B 2 NwM =
光盘 A 2 z<_{m4I;
手机 B 3 w C]yE\P1
手机 C 3 *{:FPmDU
23、说明:初始化表table1 >L#&L?#
TRUNCATE TABLE table1 pc}Q_~e
24、说明:选择从10到15的记录 7dI+aJ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc c_a*{L|c
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三、技巧 J!%Yy\G
1、1=1,1=2的使用,在SQL语句组合时用的较多 Y1EN|!WZ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~=(?Z2UDA_
如: 7(na?Z$
if @strWhere !='' Q(gu";&
begin \Oh9)X:I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }K9Vr!
end -?<wvUbR{
else q{Hk27kt
begin uc~PKU?tO
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' D8slSX`6j
end O-:#Q(H!
我们可以直接写成 C/%umazP9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ftsr-3!Vm
2、收缩数据库 -tZ2
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--重建索引 PH97O`"
DBCC REINDEX hu[=9#''$
DBCC INDEXDEFRAG <9eQ
--收缩数据和日志 Wfkm'BnV
DBCC SHRINKDB Jis{k$4
DBCC SHRINKFILE YMLo~j4J
3、压缩数据库 1eI>Yy>}
dbcc shrinkdatabase(dbname) ftF?T.dx
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' By6C+)up
go NZYtA7
5、检查备份集 <I'kJ{"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' MGX %U6
6、修复数据库 x_{ua0BLDf
ALTER DATABASE [dvbbs] SET SINGLE_USER F>2t=r*9
GO fHYEK~!C04
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cqr!*
GO eSoOJ[&$
ALTER DATABASE [dvbbs] SET MULTI_USER Wcn3\v6_
GO Y&`Vs(
7、日志清除 $bh2zKB)
SET NOCOUNT ON ~\DC
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DECLARE @LogicalFileName sysname, ~}w(YQy=y
@MaxMinutes INT, &$jg *Kr
@NewSize INT hf0G-r_ow
USE tablename -- 要操作的数据库名 qO[6?q=c:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 VkhZt7]K}B
@MaxMinutes = 10, -- Limit on time allowed to wrap log. n@{fqj
@NewSize = 1 -- 你想设定的日志文件的大小(M) T^S|u8f
-- Setup / initialize _WtX8
DECLARE @OriginalSize int F%bv
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SELECT @OriginalSize = size A{\7HV 5
FROM sysfiles q%
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WHERE name = @LogicalFileName o+`W
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bP&o]?dN
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %l[Cm4
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1K^blOLXe
FROM sysfiles rX%#Q\0h
WHERE name = @LogicalFileName -% PUY(
CREATE TABLE DummyTrans =A9>Ej/
(DummyColumn char (8000) not null) *aS|4M-
DECLARE @Counter INT, 6 +^V
@StartTime DATETIME, *RUB`tEL
@TruncLog VARCHAR(255) iyU@|^B"Wa
SELECT @StartTime = GETDATE(), |uV1S^!A
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' a)PBC{I
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )-|A|1Uo
EXEC (@TruncLog) n'7 3DApW
-- Wrap the log if necessary. ;SeDxyKG
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired @)m[:n
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) UP 1Y3
AND (@OriginalSize * 8 /1024) > @NewSize W"AWhi{h
BEGIN -- Outer loop. 2:MB u5**
SELECT @Counter = 0 3X*;.'#Z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) f(
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BEGIN -- update fo&q/;l\
INSERT DummyTrans VALUES ('Fill Log') X_+`7yCi"x
DELETE DummyTrans .\X/o!xC
SELECT @Counter = @Counter + 1 zA9N<0[]o
END 6(B0gBCId
EXEC (@TruncLog) 9c9-1iS
END vLDMa>
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2V/A%
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ;gy_Q f2U
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' >k*QkIyq
FROM sysfiles u!oHP
WHERE name = @LogicalFileName a+)Yk8%KY
DROP TABLE DummyTrans f'TjR#w
SET NOCOUNT OFF sn2SDHY
8、说明:更改某个表 ?`AzgM[I
exec sp_changeobjectowner 'tablename','dbo' ?*K;+@EH
9、存储更改全部表 f'\I52;FB
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch {}N* e"<O
@OldOwner as NVARCHAR(128), wJ1qJ!s@
@NewOwner as NVARCHAR(128) lg&"=VXx51
AS %;^[WT`,
DECLARE @Name as NVARCHAR(128) g$ZgR)q
DECLARE @Owner as NVARCHAR(128) MA.1t
DECLARE @OwnerName as NVARCHAR(128) 4otB1{
DECLARE curObject CURSOR FOR p]*$m=t0r
select 'Name' = name, r.xGvo{iY
'Owner' = user_name(uid) Vm_y,;/(-R
from sysobjects 8\!0yM#yK
where user_name(uid)=@OldOwner Q/\
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order by name IpGq_TU
OPEN curObject fC.-* r
FETCH NEXT FROM curObject INTO @Name, @Owner 4o9#B:N]J
WHILE(@@FETCH_STATUS=0) hz<kR@k}
BEGIN hUSr1jlA
if @Owner=@OldOwner WTA0S}pT
begin ml.l( 6A
set @OwnerName = @OldOwner + '.' + rtrim(@Name) iBwl(,)?m2
exec sp_changeobjectowner @OwnerName, @NewOwner l6Ze6X I
end ?JzLn,&
-- select @name,@NewOwner,@OldOwner g?A4C`l6iy
FETCH NEXT FROM curObject INTO @Name, @Owner J*U,kyYF
END 5oGnPF
close curObject knh^q;q*
deallocate curObject mV@.JFXKP
GO "Vho`x3
10、SQL SERVER中直接循环写入数据 y^Oj4Y:
declare @i int 8^\DQ&D
set @i=1 ?'P8H^K6u
while @i<30 5aL0N
begin jbpnCUzi
insert into test (userid) values(@i) %FT F
set @i=@i+1 tNjb{(eO\h
end {G&K_~Vj
小记存储过程中经常用到的本周,本月,本年函数 Tcz67&c |W
Dateadd(wk,datediff(wk,0,getdate()),-1) uZz^>*b
Dateadd(wk,datediff(wk,0,getdate()),6) Z$X2*k6PK
Dateadd(mm,datediff(mm,0,getdate()),0) 37?%xQ!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?T7`E q
Dateadd(yy,datediff(yy,0,getdate()),0) "@Ra>qb
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %((F}9_6
上面的SQL代码只是一个时间段 ppR~e*rv-
Dateadd(wk,datediff(wk,0,getdate()),-1) =\J^_g4-l
Dateadd(wk,datediff(wk,0,getdate()),6) =:P9 $
就是表示本周时间段. @Rig@
下面的SQL的条件部分,就是查询时间段在本周范围内的:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) h#^IT
而在存储过程中 @NlnZfMu
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) QL-((dZ<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 7F4$k4r<