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。 (!N|Kl
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一、基础 :08,JL{
1、说明:创建数据库 W#sU`T
CREATE DATABASE database-name ^v`\x5"Vp
2、说明:删除数据库 Z)aUt
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drop database dbname fwf$Co+R:*
3、说明:备份sql server LE>]8[f6S
--- 创建 备份数据的 device d<N:[Y\4l
USE master zI<<Q2
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ,WB{i^TD
--- 开始 备份 \} :PLCKT
BACKUP DATABASE pubs TO testBack Q)[C?obd v
4、说明:创建新表 <3hRyG@vB
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) H+Sz=tg5
根据已有的表创建新表: 7x4PaX(
A:create table tab_new like tab_old (使用旧表创建新表) w
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B:create table tab_new as select col1,col2... from tab_old definition only 5N&?KA-
5、说明:删除新表 \)?HJ
drop table tabname X*Prl l(
6、说明:增加一个列 'u b@]ru|
Alter table tabname add column col type 1HZO9cXJ
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。 .=jay{
7、说明:添加主键: Alter table tabname add primary key(col) b`O'1r\Y;
说明:删除主键: Alter table tabname drop primary key(col) KNIn:K^/
8、说明:创建索引:create [unique] index idxname on tabname(col....) [ ~&/s:Vvo
删除索引:drop index idxname vTzlwK\#1
注:索引是不可更改的,想更改必须删除重新建。 7Da`
9、说明:创建视图:create view viewname as select statement R',rsGd`6j
删除视图:drop view viewname wT8DSq
10、说明:几个简单的基本的sql语句 sI^Xb@'09$
选择:select * from table1 where 范围 P! #[mio
插入:insert into table1(field1,field2) values(value1,value2) I75DUJqy]
删除:delete from table1 where 范围 -0x
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更新:update table1 set field1=value1 where 范围 (S\[Y9
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! }oGA-Qc}B
排序:select * from table1 order by field1,field2 [desc] 'Xq|Kf (
总数:select count as totalcount from table1 ~<F8ug#
求和:select sum(field1) as sumvalue from table1 EVC]sUT
平均:select avg(field1) as avgvalue from table1 &H/'rd0M
最大:select max(field1) as maxvalue from table1 zL `iK"N`
最小:select min(field1) as minvalue from table1 lBvR+9Qw
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11、说明:几个高级查询运算词 G.a b ql
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A: UNION 运算符 co|aC!7
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。 9} M?P
B: EXCEPT 运算符 .Una+Z
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。 NzOx0WLF
C: INTERSECT 运算符 W^LY'ypT
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。 a:IC)]j$_
注:使用运算词的几个查询结果行必须是一致的。 Ep3N&Imp
12、说明:使用外连接 k(7&N0V%zz
A、left outer join: -23w2Qt
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。 xvl#w
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 4`]^@"{
B:right outer join: /quc}"__
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。 A:N|\Mv2b
C:full outer join:
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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。 <~'"<HwtK
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二、提升 sF?TmBQ*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) sn$9Shgh
法一:select * into b from a where 1<>1 ju8q?Nyhs
法二:select top 0 * into b from a >xYpNtEs
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) BBRR)
insert into b(a, b, c) select d,e,f from b; a /l)qB#
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) 1AfnzGvA
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 -)]Yr #Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. BsqP?/
4、说明:子查询(表名1:a 表名2:b) ex9g?*Q
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) %D}kD6=
5、说明:显示文章、提交人和最后回复时间 xH(lm2kvT
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Tx=-Bb~;
6、说明:外连接查询(表名1:a 表名2:b) ag#S6E^%S
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8Pn#+IvCE
7、说明:在线视图查询(表名1:a ) %x{kc3PnO
select * from (SELECT a,b,c FROM a) T where t.a > 1; m=A(NKZ
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 >G*eNn
select * from table1 where time between time1 and time2 foF({4q7b^
select a,b,c, from table1 where a not between 数值1 and 数值2 ](9Xvy
9、说明:in 的使用方法 q?oP?cCw
select * from table1 where a [not] in ('值1','值2','值4','值6') wQH<gJE/:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (*nT(Adk
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) K>r,(zgVc
11、说明:四表联查问题: &(G\[RWp\
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 ..... gk[aM~p
12、说明:日程安排提前五分钟提醒 3kIN~/<R+7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "9P>a=Y
13、说明:一条sql 语句搞定数据库分页 # 448-8x
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 % X+:o]T
14、说明:前10条记录 j4qR(p(vC
select top 10 * form table1 where 范围 K{cD+=]{
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*4-.*U8a
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ox>^>wR*
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 O=&0 H|B
(select a from tableA ) except (select a from tableB) except (select a from tableC) m!4ndO;0vh
17、说明:随机取出10条数据 g\(G\ tnu>
select top 10 * from tablename order by newid() )}]g]
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18、说明:随机选择记录 S)k*?dQ##R
select newid() I<4Pur>"
19、说明:删除重复记录 gsvuE
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) " 4K(jXq|
20、说明:列出数据库里所有的表名 nntuLuW
select name from sysobjects where type='U' w%VU/6~
21、说明:列出表里的所有的 1N^[.=
select name from syscolumns where id=object_id('TableName') *,)Md[
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。 FLCexlv^
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 Zq|I,l0+E
显示结果: z^q0/'
type vender pcs u\x}8pn
电脑 A 1 ;|5F[
电脑 A 1 +L|?~p`V
光盘 B 2 ooL!TSGD
光盘 A 2 y$F'(b|)
手机 B 3 N/'b$m5=
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手机 C 3 BB$>h}
23、说明:初始化表table1 %lx!.G
TRUNCATE TABLE table1 |y#
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24、说明:选择从10到15的记录 Y3cMC)
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ;Ax
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三、技巧 ]z;I_-
1、1=1,1=2的使用,在SQL语句组合时用的较多 18d4fR
"where 1=1" 是表示选择全部 "where 1=2"全部不选, g i-$ZFzB
如: R)(T^V`{
if @strWhere !='' K5VWt)Z#
begin nH'e?>x~e
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere F>6|3bOR
end (sTpmQx,b
else ]^'Kd*x
begin \?ZB]*Fu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' YnS#H"
end y`5
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我们可以直接写成 YQ)kRhFA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere f4b/NG|
2、收缩数据库 e8!5I,I
--重建索引 =tn)}Y.<e
DBCC REINDEX rgv?gaQ>
DBCC INDEXDEFRAG l
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--收缩数据和日志 w"|L:8
DBCC SHRINKDB !cLo>,4
DBCC SHRINKFILE a=1@*ID
3、压缩数据库 8.=BaNU
dbcc shrinkdatabase(dbname) =.U[$~3q%
4、转移数据库给新用户以已存在用户权限 q=m'^
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exec sp_change_users_login 'update_one','newname','oldname' <C iSK!
go ]t,BMu=%
5、检查备份集 O`\;e>!t
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @6sqMw}
6、修复数据库 |\t-g"~sN
ALTER DATABASE [dvbbs] SET SINGLE_USER 7~p@0)''
GO b<ZIWfs
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK PO^ij2eS
GO '<xXK@=KEI
ALTER DATABASE [dvbbs] SET MULTI_USER "ycJ:Xv49
GO P%VSAh\|n
7、日志清除 6=/F$|
SET NOCOUNT ON mb3"U"ohs
DECLARE @LogicalFileName sysname, |4zIfAO
@MaxMinutes INT, cn3\kT*
@NewSize INT su(1<S}
USE tablename -- 要操作的数据库名 rJTa
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 F6|]4H.3Q
@MaxMinutes = 10, -- Limit on time allowed to wrap log. RVmh6m
@NewSize = 1 -- 你想设定的日志文件的大小(M) EU;9*W<
-- Setup / initialize eHZws`W
DECLARE @OriginalSize int
(@VMH !3
SELECT @OriginalSize = size e}7lBLK]*
FROM sysfiles 'ya{9EdlT
WHERE name = @LogicalFileName yYYSeH
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^*Q ?]N
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 7"x;~X
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g%I"U>!2
FROM sysfiles xml7Uarc
WHERE name = @LogicalFileName pRpBhm;iJ
CREATE TABLE DummyTrans ]^7@}Ce_
(DummyColumn char (8000) not null) wv1iSfW
DECLARE @Counter INT, zxl@(hd
@StartTime DATETIME, pa3{8x{9m
@TruncLog VARCHAR(255) iy!=6
SELECT @StartTime = GETDATE(), 5H9z4-i x?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 783,s_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $GcqBg-Hi
EXEC (@TruncLog) P4'Q/Sj
-- Wrap the log if necessary. $( kF#
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired p27~>xQ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) SHgN~Um
AND (@OriginalSize * 8 /1024) > @NewSize v{N`.~,^
BEGIN -- Outer loop. R+z2}}Z!`
SELECT @Counter = 0 Gj?t_Zln
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3(N$nsi
BEGIN -- update H$t_Xw==
INSERT DummyTrans VALUES ('Fill Log') s
5Qcl;}
DELETE DummyTrans \?-<4Bc@
SELECT @Counter = @Counter + 1 JFmC\
END pYEMmZ?L
EXEC (@TruncLog) 7xlkZF
END X`K<>0.N
SELECT 'Final Size of ' + db_name() + ' LOG is ' + lrE5^;/s1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 8/#A!Ww]
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB'
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FROM sysfiles I$G['`XX/
WHERE name = @LogicalFileName gz9j&W.
DROP TABLE DummyTrans JPHL#sKyz
SET NOCOUNT OFF J*A,o~U|
8、说明:更改某个表 V=l0(03j~
exec sp_changeobjectowner 'tablename','dbo' G~a ZJ,
9、存储更改全部表 {}przrU^c
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch &Z@o Q
@OldOwner as NVARCHAR(128), RbnVL$c
@NewOwner as NVARCHAR(128) N>`Aw^ _@&
AS +Kc
DECLARE @Name as NVARCHAR(128) &r/Mi%
DECLARE @Owner as NVARCHAR(128) $%d*@'c
DECLARE @OwnerName as NVARCHAR(128) V f&zL
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DECLARE curObject CURSOR FOR FD
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select 'Name' = name, O0v}43J[
'Owner' = user_name(uid) PFjL1=7I
from sysobjects 9$w.9`Py
where user_name(uid)=@OldOwner qe#tj/aZ
order by name 0[(8
OPEN curObject ? OM!+O
FETCH NEXT FROM curObject INTO @Name, @Owner !f[_+CD
WHILE(@@FETCH_STATUS=0) <'oQ \eB
BEGIN PC8Q"O
if @Owner=@OldOwner (ZZ8L-s
begin >+1duAC
set @OwnerName = @OldOwner + '.' + rtrim(@Name) cV6D<,)
exec sp_changeobjectowner @OwnerName, @NewOwner ED gag
end .`eN8Dl1
-- select @name,@NewOwner,@OldOwner Dz/ "M=
FETCH NEXT FROM curObject INTO @Name, @Owner T!#GW/?
END + &Eqk
close curObject [9L:),&u
deallocate curObject _V6ukd"B~
GO \M^bD4';>
10、SQL SERVER中直接循环写入数据 ~36!?&eA8
declare @i int CHX #^0m.
set @i=1 8GUX{K
while @i<30 rb.N~
begin N4!O.POP
insert into test (userid) values(@i) F$]Pk|,
set @i=@i+1 ZY+qA
end ;A*]l'[-
小记存储过程中经常用到的本周,本月,本年函数 oMa6(3T?E
Dateadd(wk,datediff(wk,0,getdate()),-1) I\ob7X'Xu!
Dateadd(wk,datediff(wk,0,getdate()),6) lymCH
Dateadd(mm,datediff(mm,0,getdate()),0) NXrlk
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) W${Ue#w77
Dateadd(yy,datediff(yy,0,getdate()),0) )ez9"# MH'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 99QU3c<.
上面的SQL代码只是一个时间段 m-, x<bM?
Dateadd(wk,datediff(wk,0,getdate()),-1) DvvK^+-~
Dateadd(wk,datediff(wk,0,getdate()),6) gM:".Ee
就是表示本周时间段. 4!?eRY
下面的SQL的条件部分,就是查询时间段在本周范围内的: F JyT+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) sO@Tf\d
而在存储过程中 =7eV/3
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) O\r0bUPE
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~9@UjQ^)F