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。 ;O#g"8
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一、基础 n> w`26MMp
1、说明:创建数据库 cNK)5-
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CREATE DATABASE database-name nhT(P`6
2、说明:删除数据库 9.OA, 6
drop database dbname ]/2T\w.<
3、说明:备份sql server @r7:NU}
--- 创建 备份数据的 device l&(l$@t
USE master 3c'#6virz
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8;gXg
--- 开始 备份 8F5|EpB9M
BACKUP DATABASE pubs TO testBack 'xK.UI
4、说明:创建新表 UmU:j@xvg
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) S]/b\B.h+
根据已有的表创建新表: n%%7KTqu
A:create table tab_new like tab_old (使用旧表创建新表) ?;ukvD
B:create table tab_new as select col1,col2... from tab_old definition only -.I4-6~
5、说明:删除新表 h) (*q+a
drop table tabname !kuX,*}q
6、说明:增加一个列 /8yn vhF#
Alter table tabname add column col type QrYa%D+
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。 eCbf9B
7、说明:添加主键: Alter table tabname add primary key(col) p^)B0[P9
说明:删除主键: Alter table tabname drop primary key(col) Z9`TwS@x[
8、说明:创建索引:create [unique] index idxname on tabname(col....) ~W0(1#
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删除索引:drop index idxname ~eh0[mF^]
注:索引是不可更改的,想更改必须删除重新建。 0DPxW8Y -`
9、说明:创建视图:create view viewname as select statement &p(0K4:
删除视图:drop view viewname wVl+]zB
10、说明:几个简单的基本的sql语句 -%c<IX>z9
选择:select * from table1 where 范围 }%!tT\8
插入:insert into table1(field1,field2) values(value1,value2) ^V*-1r1
删除:delete from table1 where 范围 0?Q_@Y
更新:update table1 set field1=value1 where 范围 -b;|q.!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! rVSZ.+n
排序:select * from table1 order by field1,field2 [desc] W_YY#wf_
总数:select count as totalcount from table1 ?}p:J{
求和:select sum(field1) as sumvalue from table1 nA7M8HB
平均:select avg(field1) as avgvalue from table1 C|-pD
最大:select max(field1) as maxvalue from table1 T3%C%BcX
最小:select min(field1) as minvalue from table1 k\)Cw
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11、说明:几个高级查询运算词 d3Di/Iej
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A: UNION 运算符 MmTC=/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。 D1s4`V -
B: EXCEPT 运算符 .3qu9eP
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。 .N m su+s
C: INTERSECT 运算符 T?
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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。 "UVFU-Z
注:使用运算词的几个查询结果行必须是一致的。 s 0u{dqP
12、说明:使用外连接 _D7 ]-3uC!
A、left outer join: hcCp,b
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。 csZc|kDI
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 V7Yaks
B:right outer join: ShOX<Fb&
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。 eet Q}]
C:full outer join: C#pZw[
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。 Ucw yxXI
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二、提升 Y]|:?G7l]
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [/M^[p
法一:select * into b from a where 1<>1 E6B!+s!]
法二:select top 0 * into b from a 9O.Y OiW
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) a`Qot
insert into b(a, b, c) select d,e,f from b; d@C&+#QDF
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) )v4b
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 m^~ S
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. eJCjJ)
4、说明:子查询(表名1:a 表名2:b) 6vKS".4C
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) o]n!(f<(*
5、说明:显示文章、提交人和最后回复时间 sM[I4.A3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b siDh="{s
6、说明:外连接查询(表名1:a 表名2:b) 13'vH]S$M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $
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7、说明:在线视图查询(表名1:a ) OFkNl}D
select * from (SELECT a,b,c FROM a) T where t.a > 1; YcX/{L[9o
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 -Y 9SngxM
select * from table1 where time between time1 and time2 zvc`3
select a,b,c, from table1 where a not between 数值1 and 数值2 zSvgKmNY
9、说明:in 的使用方法 *u6Y8IL1
select * from table1 where a [not] in ('值1','值2','值4','值6') (h-*_a}F4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ,Tagj`@bHc
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oB1>x^
11、说明:四表联查问题: /\s}uSW
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 ..... SlLw{Yb7\.
12、说明:日程安排提前五分钟提醒 R8ONcG
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 o PKr*
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13、说明:一条sql 语句搞定数据库分页 K0+.q?8D|
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 7xo4-fIuT
14、说明:前10条记录 RC#C\S6
select top 10 * form table1 where 范围 4674SzL
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.) F|bYWYED;
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ikB Yd
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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 va|*c22;|
(select a from tableA ) except (select a from tableB) except (select a from tableC) Q?t^@
17、说明:随机取出10条数据 2I1uX&g
select top 10 * from tablename order by newid() NG&_?|OmV
18、说明:随机选择记录 N/QiI.V6
select newid() <+#oBN
19、说明:删除重复记录 kUx&pYv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 3-Dt[0%{
20、说明:列出数据库里所有的表名 w2O!M!1
select name from sysobjects where type='U' ?jQ](i&
21、说明:列出表里的所有的 :p&!RI(l
select name from syscolumns where id=object_id('TableName') M]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。 AwUi+|7r])
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 RZpcXv
显示结果: <N,)G
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type vender pcs 1_'? JfY-
电脑 A 1 j VgFZ,
电脑 A 1 X6+qpp
光盘 B 2 VQI(Vp|
光盘 A 2 E`H$YS3o
手机 B 3 XZNY4/25G
手机 C 3 -m=
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23、说明:初始化表table1 m9}AG Rj
TRUNCATE TABLE table1 DmVP
24、说明:选择从10到15的记录 GV6K/T:
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^I
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三、技巧 $2DuB
1、1=1,1=2的使用,在SQL语句组合时用的较多 R
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, )\;Z4x;]U
如: q*![AzFh
if @strWhere !='' i|)Su4Dw
begin 6&Juv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5m:i6,4
end RyB~Lm`ZK%
else X;F?:Iw \
begin 8;Fn7k_Uf
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' e}VBRvr
end u,3,ck!B>@
我们可以直接写成 s#Jh -+lM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :HxA`@Ok
2、收缩数据库 HpEQEIvt
--重建索引 7`IpBm<
DBCC REINDEX yV3^Qtb!
DBCC INDEXDEFRAG ZD#9&q'4<
--收缩数据和日志 \AUI|M;'
DBCC SHRINKDB =$8nUX`
DBCC SHRINKFILE 0Z<I%<8bK
3、压缩数据库 tj]9~eJ-
dbcc shrinkdatabase(dbname) ZlYPoOq
4、转移数据库给新用户以已存在用户权限 *=ZsqOHwG
exec sp_change_users_login 'update_one','newname','oldname' U'UQ|%5f
go Ch()P.n?
5、检查备份集 qjAWeS/
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' /N>e&e[35\
6、修复数据库 1T_QX9
ALTER DATABASE [dvbbs] SET SINGLE_USER h0oMTiA
GO ]9=h%5Ji>
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK H`8``#-|@S
GO qa(>wR"mT
ALTER DATABASE [dvbbs] SET MULTI_USER ,6!rR,0
GO plu$h-$d
7、日志清除 p47S^gW
SET NOCOUNT ON &bz:K8c
DECLARE @LogicalFileName sysname, GSoZx0
@MaxMinutes INT, qrvsjYi*w
@NewSize INT -5>-%13
USE tablename -- 要操作的数据库名 G'zF)0oD
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ;VO.!5W@eg
@MaxMinutes = 10, -- Limit on time allowed to wrap log. aKUS5jDu
@NewSize = 1 -- 你想设定的日志文件的大小(M) \?j E#^
-- Setup / initialize 8By,#T".
DECLARE @OriginalSize int O<)y-nx;X
SELECT @OriginalSize = size 22<0DhJ
FROM sysfiles ?.c;oS|
WHERE name = @LogicalFileName +#b:d=v!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0c.s
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }),w1/#5u8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 9%ii '{
FROM sysfiles FEPXuCb
WHERE name = @LogicalFileName Glq85S
CREATE TABLE DummyTrans ]nQt>R p_
(DummyColumn char (8000) not null) r!P}u
DECLARE @Counter INT, 2>-S-;i
@StartTime DATETIME,
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@TruncLog VARCHAR(255) RO0>I8c1c
SELECT @StartTime = GETDATE(), 3Y)PU=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S0g'r
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) @ DZD
EXEC (@TruncLog) =Cv/Y%DN
-- Wrap the log if necessary. ;Z j]~|
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired bsxTqJ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #>Y'sd5'A
AND (@OriginalSize * 8 /1024) > @NewSize vhvdKD
BEGIN -- Outer loop. ]J9cVp
SELECT @Counter = 0 133I.XBU
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
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BEGIN -- update &bgvy'p
INSERT DummyTrans VALUES ('Fill Log') P^MOx4
DELETE DummyTrans G5dO 3lwq
SELECT @Counter = @Counter + 1 q(5j(G ;
END r[.>P$U
EXEC (@TruncLog) Y
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END p\C%%
SELECT 'Final Size of ' + db_name() + ' LOG is ' + wpA`(+J
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + % |q0-x
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' G>YAJo
FROM sysfiles (vR 9H(#
WHERE name = @LogicalFileName a</D_66
DROP TABLE DummyTrans ?Y:x[pOe
SET NOCOUNT OFF ;)Kh;;e
8、说明:更改某个表 &`Y!;@K9W#
exec sp_changeobjectowner 'tablename','dbo' xX0-]Y h:
9、存储更改全部表 Cp^@zw*/
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch d"G+8}.4
@OldOwner as NVARCHAR(128), (nW67YTr
@NewOwner as NVARCHAR(128) PCd0 ?c
AS KucV3-I
DECLARE @Name as NVARCHAR(128) VHOfaCE
DECLARE @Owner as NVARCHAR(128) xRuFuf8
DECLARE @OwnerName as NVARCHAR(128) C
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DECLARE curObject CURSOR FOR 6m .k;'
select 'Name' = name, ~,D@8tv
'Owner' = user_name(uid) p3ISWJa!
from sysobjects `"i Y*
where user_name(uid)=@OldOwner Q@e[5RA+]
order by name Mcw4!{l`
OPEN curObject n[Zz]IO,g
FETCH NEXT FROM curObject INTO @Name, @Owner , "jbq~
WHILE(@@FETCH_STATUS=0) pqvOJ#?Q}=
BEGIN 3QI?[R.
if @Owner=@OldOwner %xwIt~Y
begin )Fd
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) rQ4*k'lA:
exec sp_changeobjectowner @OwnerName, @NewOwner 4fh^[\
end 0s#vwK13
-- select @name,@NewOwner,@OldOwner }MR1^
FETCH NEXT FROM curObject INTO @Name, @Owner 7;.xc{
END -Z4{;I[Q@
close curObject +u@aJ_^
deallocate curObject X.ONa_
GO .*=]gZ$IE
10、SQL SERVER中直接循环写入数据 $=sXAK9
declare @i int IUGz =%[
set @i=1 A>VI{
while @i<30 i$^)UZJ&0
begin [=uo1%
insert into test (userid) values(@i) DfJ2PX}q
set @i=@i+1 d#:3be{|&q
end W$dn_9W
小记存储过程中经常用到的本周,本月,本年函数 v]2S`ffP
Dateadd(wk,datediff(wk,0,getdate()),-1) q,<[hBri-
Dateadd(wk,datediff(wk,0,getdate()),6) O#nR>1h
Dateadd(mm,datediff(mm,0,getdate()),0) _ 7oV<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) k<w(i
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Dateadd(yy,datediff(yy,0,getdate()),0) D+ V7hpH-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Mv|ykJoz"
上面的SQL代码只是一个时间段 &