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。 91-o}|3v
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一、基础 6){]1h"
1、说明:创建数据库 /Uy"M:|V1
CREATE DATABASE database-name "PTZ%7YH}
2、说明:删除数据库 !1 8clL
drop database dbname d,Yw5$i
3、说明:备份sql server };jN\x?&q
--- 创建 备份数据的 device 8sTp`}54J
USE master v8[I8{41
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' v)t:|Q{I
--- 开始 备份 27O|).yKX
BACKUP DATABASE pubs TO testBack cir$voL
4、说明:创建新表 jiS_G%G
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) DiwxXqY
根据已有的表创建新表: g<f <Ip=
A:create table tab_new like tab_old (使用旧表创建新表) ;=;
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B:create table tab_new as select col1,col2... from tab_old definition only vyX\'r.~7
5、说明:删除新表 92x(u%~E
drop table tabname ERE)A-8
6、说明:增加一个列 vMt/u?oB
Alter table tabname add column col type :f}9($
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。 fS [,vPl
7、说明:添加主键: Alter table tabname add primary key(col) Hmd]
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说明:删除主键: Alter table tabname drop primary key(col) h
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8、说明:创建索引:create [unique] index idxname on tabname(col....) P.;aMRMR
删除索引:drop index idxname QWSTR\!
注:索引是不可更改的,想更改必须删除重新建。 IsM}'.
9、说明:创建视图:create view viewname as select statement rrqR}}l
删除视图:drop view viewname ],FMwCI
10、说明:几个简单的基本的sql语句 `c5"d
选择:select * from table1 where 范围 f~y%%+{p
插入:insert into table1(field1,field2) values(value1,value2) X>(TrdK_9"
删除:delete from table1 where 范围 F6OpN"UM'
更新:update table1 set field1=value1 where 范围 UA8GL D9
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! O%(fx!c`
排序:select * from table1 order by field1,field2 [desc] gL[yA?GoM
总数:select count as totalcount from table1 YoZFwRQU
求和:select sum(field1) as sumvalue from table1 ,dov<U[ia
平均:select avg(field1) as avgvalue from table1 o-{[|/)Tk
最大:select max(field1) as maxvalue from table1 QnXA*6DJ
最小:select min(field1) as minvalue from table1 Vq5k+3W+
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11、说明:几个高级查询运算词 D 38$`j
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A: UNION 运算符 i2YuOV!
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 V |/NB
B: EXCEPT 运算符 *:t|qgJI#+
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 XZJ+h,f
C: INTERSECT 运算符 >.'*)@vQi
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 #PanfYR
注:使用运算词的几个查询结果行必须是一致的。 3'qJ/*]9
12、说明:使用外连接 ph [#QHB
A、left outer join: n'01Hh`0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 #qI= Z0Y
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ll6wpV0m
B:right outer join: qT"Q1xU[
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 t!x5 fNo)
C:full outer join: m&\h4$[kql
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。 S<u-n8bv
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二、提升 < hO
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ryCI>vJz
法一:select * into b from a where 1<>1 J6%AH?Mt
法二:select top 0 * into b from a I1\a[Xe8E
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Eu-RNrYh#
insert into b(a, b, c) select d,e,f from b;
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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) w{uuSe
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $Y_i4(
4、说明:子查询(表名1:a 表名2:b) (v|}\?L
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) no]z1D
5、说明:显示文章、提交人和最后回复时间 80&.JP.
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b m-DsY
6、说明:外连接查询(表名1:a 表名2:b) XC "'Q+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c %4
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7、说明:在线视图查询(表名1:a ) !]fQ+ *X0g
select * from (SELECT a,b,c FROM a) T where t.a > 1; J.dLPKU;-
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ivz>dJ ?T
select * from table1 where time between time1 and time2 rBTeb0i?
select a,b,c, from table1 where a not between 数值1 and 数值2 f0<%&2ym
9、说明:in 的使用方法 Ru>uL@w
select * from table1 where a [not] in ('值1','值2','值4','值6') Ck@J,~x1D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ^Q ps>A(
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) b0A1hb[|
11、说明:四表联查问题: !F4@KAv
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *^wB!{.#
12、说明:日程安排提前五分钟提醒 7 aYn0_NKp
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )0e2ic/
13、说明:一条sql 语句搞定数据库分页 bb`':3%
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ;?~$h-9)
14、说明:前10条记录 "zY](P
select top 10 * form table1 where 范围 u#A<hq;
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.) P"?FnTbv[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) e)IpPTj#
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 f%)zg(YlO
(select a from tableA ) except (select a from tableB) except (select a from tableC) G,<T/f
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17、说明:随机取出10条数据 ]I.n\2R]om
select top 10 * from tablename order by newid() iy\nio`
18、说明:随机选择记录 X _G| hx
select newid() (NK9vW4F
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) q4$+H{xB
20、说明:列出数据库里所有的表名 :@xm-.D
select name from sysobjects where type='U' qG/fE'(j&
21、说明:列出表里的所有的 ai^4'{#zi
select name from syscolumns where id=object_id('TableName') Bo+DJizu
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 J5[~LZKW
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type gx:;&4AD
显示结果: qcJft'>F
type vender pcs =GBI0&U
电脑 A 1 hv$m4,0WB
电脑 A 1 A[dvEb;r
光盘 B 2 C4#rA.nF|
光盘 A 2 p|/j4@-h
手机 B 3 EIbXmkHl<
手机 C 3 %=<IGce
23、说明:初始化表table1 iH2n.M
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TRUNCATE TABLE table1 L]hXpt
24、说明:选择从10到15的记录 FNQX7O52
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc uw7{>9
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三、技巧 zggB$5
1、1=1,1=2的使用,在SQL语句组合时用的较多 }2r+%V&4
"where 1=1" 是表示选择全部 "where 1=2"全部不选, x2#qg>`l
如: 1fL<&G
if @strWhere !='' m:O(+Fl
begin B)h>8 {
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere j#6|V]l
end rn:!dV[
else 8?Y['
begin +|%Sx
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?68uS;
end L1)@z8]
我们可以直接写成 xq-$\#O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere td -3h,\\
2、收缩数据库 bv
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--重建索引 w,j cm;
DBCC REINDEX 1(GHCxA8G
DBCC INDEXDEFRAG F X1ZG!
--收缩数据和日志 B7-RU<n
DBCC SHRINKDB dj[apuiF
DBCC SHRINKFILE w.+Eyu_I\
3、压缩数据库 N\1/JW+
dbcc shrinkdatabase(dbname) 4`2$_T$F
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' Lg`Jp&Kg
go Hwe)Tsh e
5、检查备份集 }Ewo_P&`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' mg+k'Myo+
6、修复数据库 qMS}t3X
ALTER DATABASE [dvbbs] SET SINGLE_USER K2/E#}/
GO jlKGXD)Q[
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK HrqF![_
GO K{}4zuZ
ALTER DATABASE [dvbbs] SET MULTI_USER ~k4W<
GO GG'Sp53GE
7、日志清除 <3 j~=-
SET NOCOUNT ON ~j,TVY
DECLARE @LogicalFileName sysname, ^ZQCIS-R
@MaxMinutes INT, #Y,A[Y5jX
@NewSize INT {B yn{?w
USE tablename -- 要操作的数据库名 Gbd?%{Xc-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 T }uE0Z,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. :?r*p>0$
@NewSize = 1 -- 你想设定的日志文件的大小(M) .:;fAJPf
-- Setup / initialize Q.(51]'
DECLARE @OriginalSize int ?'~;Q)
SELECT @OriginalSize = size #cEq_[yI
FROM sysfiles dB|Te "6
WHERE name = @LogicalFileName r2G*!qK*1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + gB CC
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }g,X5v?W
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 4IGxI7~27#
FROM sysfiles ehc<|O9tY
WHERE name = @LogicalFileName Tj,Nmb>Q7'
CREATE TABLE DummyTrans PF ;YE6
(DummyColumn char (8000) not null) {u]CHN`%Z
DECLARE @Counter INT, owMuT^x?
@StartTime DATETIME, 8)Tj
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@TruncLog VARCHAR(255) <J# R3{
SELECT @StartTime = GETDATE(), qU6BA\ZL
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q lY\*{x4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) rZ866\0
EXEC (@TruncLog) +IsWI;lp
-- Wrap the log if necessary. 6IF|3@yD
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired t61'LCEis
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) $u,GVq~
AND (@OriginalSize * 8 /1024) > @NewSize [oHOHp/V
BEGIN -- Outer loop. T^.{9F]*S
SELECT @Counter = 0 dt.-C_MO
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) {dZ8;Fy4
BEGIN -- update /2:Q6J
INSERT DummyTrans VALUES ('Fill Log') v =+k"gm6
DELETE DummyTrans |7S:l9;
SELECT @Counter = @Counter + 1 V9$-twhu
END 2TCRS#z
EXEC (@TruncLog) }I<N^j=/pO
END B=x~L
SELECT 'Final Size of ' + db_name() + ' LOG is ' + >\-3P$
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,yi2O]5e>!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' gx&7 3f<J
FROM sysfiles e6es0D[>5
WHERE name = @LogicalFileName \1khyF'
DROP TABLE DummyTrans +wjlAqMQ
SET NOCOUNT OFF v7$9QVze
8、说明:更改某个表 A@{ !:_55
exec sp_changeobjectowner 'tablename','dbo' j<|6s,&
9、存储更改全部表 'v`~(9'Rcj
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8I {56$
@OldOwner as NVARCHAR(128), %[+/>e/m
@NewOwner as NVARCHAR(128) qSCTFJ0
AS 6A@Lj*:2m
DECLARE @Name as NVARCHAR(128) $u-lo|
DECLARE @Owner as NVARCHAR(128) {C, #rj
DECLARE @OwnerName as NVARCHAR(128) IM|Se4;x
DECLARE curObject CURSOR FOR Cg?I'1]o6
select 'Name' = name, -q|*M:R
'Owner' = user_name(uid) \6jF{
from sysobjects >T$7{
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where user_name(uid)=@OldOwner iPJ9Gh7
order by name \c'%4Ao
OPEN curObject 2w;G4
FETCH NEXT FROM curObject INTO @Name, @Owner KXDz'9_
WHILE(@@FETCH_STATUS=0) 5]Z] j[8Y
BEGIN >pJ6{Ip
if @Owner=@OldOwner Xd5!
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begin T=Ol`?5
set @OwnerName = @OldOwner + '.' + rtrim(@Name) MgSp.<!
exec sp_changeobjectowner @OwnerName, @NewOwner gx&\Kw6HM
end cKSfqqPm$"
-- select @name,@NewOwner,@OldOwner }$&);7(w
FETCH NEXT FROM curObject INTO @Name, @Owner <(ubZ
END HK=CP0H
close curObject Rb yF#[}
deallocate curObject Zt7hzW
GO }b<87#Nb9R
10、SQL SERVER中直接循环写入数据 'XG:1Bpm
declare @i int 6qY\7R2+
set @i=1 D'Jm!Ap
while @i<30 /"g[Ay
begin ;N9n'Sq4
insert into test (userid) values(@i) lsN/$M|}
set @i=@i+1 LJ:mJ#
end D6"~fjHh
小记存储过程中经常用到的本周,本月,本年函数 KLj 4LOs
Dateadd(wk,datediff(wk,0,getdate()),-1) n+:m_2T
Dateadd(wk,datediff(wk,0,getdate()),6) U`HXsq
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Dateadd(mm,datediff(mm,0,getdate()),0) ]wJ}-#Kx
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @|jKO5Y
Dateadd(yy,datediff(yy,0,getdate()),0) ^M[-K`c }
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -d\AiT
上面的SQL代码只是一个时间段 d)pz
Dateadd(wk,datediff(wk,0,getdate()),-1) )ylv(qgV
Dateadd(wk,datediff(wk,0,getdate()),6) ~pDRF(
就是表示本周时间段. vCYSm 0
下面的SQL的条件部分,就是查询时间段在本周范围内的: Qq@_Z=mt
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Vq? 8u/
而在存储过程中 ,'/HcF?yf
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HMl!?%%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ;H D 4~3