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。 Br!&Y9
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一、基础 !AHm+C_=Lg
1、说明:创建数据库 _q$fw&
CREATE DATABASE database-name `roSOX1f
2、说明:删除数据库 Oei2,3l,?
drop database dbname (%!R
3、说明:备份sql server m(P)oqwM
--- 创建 备份数据的 device c!T{|'?
USE master sn#h=,*4`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Al]9/ML/m
--- 开始 备份 Q7%#3ML
BACKUP DATABASE pubs TO testBack 8hp]+k_y
4、说明:创建新表 YTh4&wm
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) eP?|U.on
根据已有的表创建新表: Xlw=R2`)~
A:create table tab_new like tab_old (使用旧表创建新表) 8[ OiG9b
B:create table tab_new as select col1,col2... from tab_old definition only 2ow\d b
5、说明:删除新表 k~dr;j
drop table tabname rXX|?9'
6、说明:增加一个列 1ouTZ'c?
Alter table tabname add column col type z\5Nni/~6D
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。 0wcWDE
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7、说明:添加主键: Alter table tabname add primary key(col) 5al{[mi
说明:删除主键: Alter table tabname drop primary key(col) =SnR9In
8、说明:创建索引:create [unique] index idxname on tabname(col....) &O)mPnx`
删除索引:drop index idxname ,oe{@z{*@
注:索引是不可更改的,想更改必须删除重新建。 Dw3!
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9、说明:创建视图:create view viewname as select statement Oc`fQqYy
删除视图:drop view viewname ^*Fkt(ida
10、说明:几个简单的基本的sql语句 $)~]4n=
选择:select * from table1 where 范围 L]}|{<3\
插入:insert into table1(field1,field2) values(value1,value2) 8<
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删除:delete from table1 where 范围 K gX)fj
更新:update table1 set field1=value1 where 范围 e8.bH#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! q4N$.hpb
排序:select * from table1 order by field1,field2 [desc] MzG.Qh'z
总数:select count as totalcount from table1 kv b-=
求和:select sum(field1) as sumvalue from table1 0k 8SDRWU
平均:select avg(field1) as avgvalue from table1 7d5x4^EYE
最大:select max(field1) as maxvalue from table1 /K<Nlxcm
最小:select min(field1) as minvalue from table1 _C\b,D}p
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11、说明:几个高级查询运算词 Yw<:I&
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A: UNION 运算符 c`QsKwa
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\{Z{F%8
B: EXCEPT 运算符 ;|y,bo@sJJ
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。 \tqAv'jA|
C: INTERSECT 运算符 $u
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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。 Dn?L
注:使用运算词的几个查询结果行必须是一致的。 jGCW^#GE
12、说明:使用外连接 cD6o8v4]]
A、left outer join: L)5nb-qp
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。 *?+!(E
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 \^cn}db)
B:right outer join: JGe;$5|q8
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。 2<|5zF
C:full outer join: m}(DJ?qP
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。 G#Ow>NJ
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二、提升 4`F*] Ft
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) V2.K*CpZ7
法一:select * into b from a where 1<>1 10&A3C(E
法二:select top 0 * into b from a m.*+0NG
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Q~kwUZ
insert into b(a, b, c) select d,e,f from b; u4'Lm+&O
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) .YkKIei
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >Z%^|S9
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :xV&%Qa1
4、说明:子查询(表名1:a 表名2:b) 4
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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) 4hs4W,2!
5、说明:显示文章、提交人和最后回复时间 SccU@3.X~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?*;zS%93U9
6、说明:外连接查询(表名1:a 表名2:b) 49m/UeNZ
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c GFidriC
7、说明:在线视图查询(表名1:a ) ov~m?Y]h
select * from (SELECT a,b,c FROM a) T where t.a > 1; ~0NZx8qG
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 ')+EW"
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select * from table1 where time between time1 and time2 #C`!yU6(
select a,b,c, from table1 where a not between 数值1 and 数值2 [% jg;m
9、说明:in 的使用方法 ZU|nKt<GK
select * from table1 where a [not] in ('值1','值2','值4','值6') i=4bY[y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 QQ9Q[c
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) QI-3mqL
11、说明:四表联查问题: S;g~xo
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 ..... ?cvv!2B]T
12、说明:日程安排提前五分钟提醒 {IVqV6:
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 b/EvcN8 }
13、说明:一条sql 语句搞定数据库分页 )+G(4eIT
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 `uj`ixcR
14、说明:前10条记录 =bzTfki
select top 10 * form table1 where 范围 ^=ikxZyO
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.) d<Di;5
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w <ID<
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 Ou%>Dd5|?
(select a from tableA ) except (select a from tableB) except (select a from tableC) bCF63(0
17、说明:随机取出10条数据 a
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select top 10 * from tablename order by newid() KlPH.R3MPO
18、说明:随机选择记录 jc<3\ 7
select newid() weOMYJO;8
19、说明:删除重复记录 OW>U5 \q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) TwN8|ibVmP
20、说明:列出数据库里所有的表名 -h_v(s2
select name from sysobjects where type='U' #E1*1E
21、说明:列出表里的所有的 sw1XN?O
select name from syscolumns where id=object_id('TableName') K^S#?T|[9
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。 k[p
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 F-Ea85/K@4
显示结果: ;H^!yj5H
type vender pcs 7\xa_nrI
电脑 A 1 $I9zJ"*
电脑 A 1 :PLs A3[}
光盘 B 2 yZ{YIy~
光盘 A 2 }?JO[Q +
手机 B 3 YpL}R#
手机 C 3 ^o 5q- ;a
23、说明:初始化表table1 pkoHi'}} $
TRUNCATE TABLE table1 `u U@(
24、说明:选择从10到15的记录 Rg6>6.fk*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V)`?J)
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三、技巧 X[w9~t$\
1、1=1,1=2的使用,在SQL语句组合时用的较多 Di6:r3sEO
"where 1=1" 是表示选择全部 "where 1=2"全部不选, iY2bRXA
如: DXUI/C f
if @strWhere !='' c2C8}XJ|O
begin g#AA.@/Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~AO0(Lp
end |] YT6-?.
else (xTHin$
begin $Z j.
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' EPI*~=Z.U
end MS b{ve_
我们可以直接写成 =Yfs=+O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v=4TU\b%
2、收缩数据库 }S&{ &gh
--重建索引 CUG6|qu
DBCC REINDEX q8oEb
DBCC INDEXDEFRAG 1@y?OWC
--收缩数据和日志 xQ[YQ!l
DBCC SHRINKDB ~EN@$N^h
DBCC SHRINKFILE v<)
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3、压缩数据库 )Q8Q#S
dbcc shrinkdatabase(dbname) ei5 S <n
4、转移数据库给新用户以已存在用户权限 @MM|.#
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exec sp_change_users_login 'update_one','newname','oldname' +]6 EkZO
go %%_90t
5、检查备份集 >#ou8}0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' C@[:}ZGMV
6、修复数据库 __9673y
ALTER DATABASE [dvbbs] SET SINGLE_USER 8,R]R=
GO *w _j;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _)|!.r&)63
GO ?Cws25G
ALTER DATABASE [dvbbs] SET MULTI_USER $5A XE;~{
GO vfj Ipg%i
7、日志清除 L?P8/]DGp
SET NOCOUNT ON Zy#r<j]T
DECLARE @LogicalFileName sysname, ]-6 G'i?
@MaxMinutes INT, =nsY[ s<
@NewSize INT <7p2OPD
USE tablename -- 要操作的数据库名 \yy!?UlaI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1w5nBVC*$V
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ip4~qGJ
@NewSize = 1 -- 你想设定的日志文件的大小(M) LP\ Qwj{
-- Setup / initialize T/3UF
DECLARE @OriginalSize int U*b SM8)L*
SELECT @OriginalSize = size HDaec`j
FROM sysfiles ]oY~8HW
WHERE name = @LogicalFileName k\[2o
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 56)B/0=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + v!x[1[
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' j7W_%Yk|E
FROM sysfiles l>G#+#{
WHERE name = @LogicalFileName t.w?OyO
CREATE TABLE DummyTrans 9\xw}ph
(DummyColumn char (8000) not null) yG_#>3sD+%
DECLARE @Counter INT, s:_5p`w>
@StartTime DATETIME, J7xZo=@k
@TruncLog VARCHAR(255) w &-r
SELECT @StartTime = GETDATE(), BgRiJFa.d[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' cmI8Xf]"P-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ik,w3 }*P*
EXEC (@TruncLog) r1\.Jz
-- Wrap the log if necessary. DK-=Q~`!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired G'("-9
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U` U/|@6
AND (@OriginalSize * 8 /1024) > @NewSize N\0Sq-.
BEGIN -- Outer loop. OS,$}I[`8
SELECT @Counter = 0 t
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 52~k:"c
BEGIN -- update jPd<h{js
INSERT DummyTrans VALUES ('Fill Log') pQ>V]M
DELETE DummyTrans m/ukH{H1%
SELECT @Counter = @Counter + 1 c{<3\
END |joGrWv4
EXEC (@TruncLog) eDm,8Se
END ,lUo@+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 'FVT"M~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ia\Nj
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .UDZW*
FROM sysfiles +VeLd+Q}
WHERE name = @LogicalFileName crT[;w
DROP TABLE DummyTrans qm '$R3g
SET NOCOUNT OFF NUU}8a(K
8、说明:更改某个表 9O)>>1}*S
exec sp_changeobjectowner 'tablename','dbo' @@$
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9、存储更改全部表 EZHEJW'JnE
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =FKB)#N
@OldOwner as NVARCHAR(128), ]uZH 0
@NewOwner as NVARCHAR(128) u-W=~EO5#
AS 51&T`i
DECLARE @Name as NVARCHAR(128) f8j^a?d|
DECLARE @Owner as NVARCHAR(128) Glwpu-@X
DECLARE @OwnerName as NVARCHAR(128) {Xp.}c
DECLARE curObject CURSOR FOR ^?A+`1-
select 'Name' = name, -Av/L>TxlI
'Owner' = user_name(uid) :Y'nye3:
from sysobjects p[wjHfIq
where user_name(uid)=@OldOwner
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order by name f]lDJ?+
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OPEN curObject i6-K!
FETCH NEXT FROM curObject INTO @Name, @Owner #=tWCxf=
WHILE(@@FETCH_STATUS=0) *vb)d0}P
BEGIN @Q^;qMy
if @Owner=@OldOwner @4|/| !
begin v:>P;\]r9M
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8 2qe|XD4p
exec sp_changeobjectowner @OwnerName, @NewOwner f6#H@
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end p<jr&zVEc>
-- select @name,@NewOwner,@OldOwner NX;&V7
FETCH NEXT FROM curObject INTO @Name, @Owner '71btd1
END w7C=R8^
close curObject o#Y1Uamkf
deallocate curObject 1Y`MJ\9
GO pxF!<nN1,
10、SQL SERVER中直接循环写入数据 -K!-a'J
declare @i int e,BJD>N ?
set @i=1 G pd:k
while @i<30 ;CW$/^QNr5
begin )Ga6O2:
insert into test (userid) values(@i) M]'AA
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set @i=@i+1 o i?ak
end M~6I-HexT|
小记存储过程中经常用到的本周,本月,本年函数 /<C=9?Ok
Dateadd(wk,datediff(wk,0,getdate()),-1) usA!MMH4
Dateadd(wk,datediff(wk,0,getdate()),6) L_~G`Rb3
Dateadd(mm,datediff(mm,0,getdate()),0) "&%Hb's
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) N7_Co;#(zK
Dateadd(yy,datediff(yy,0,getdate()),0) cwroG#jGT
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %Xl@o
上面的SQL代码只是一个时间段 71%u|k8|
Dateadd(wk,datediff(wk,0,getdate()),-1) -FI1$
Dateadd(wk,datediff(wk,0,getdate()),6) fwEi//1
就是表示本周时间段. $CmTsnR1#y
下面的SQL的条件部分,就是查询时间段在本周范围内的: (07d0 <<[
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) oW_WW$+N
而在存储过程中 {x:IsQZ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V6k9L*VP
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `et<Z