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。 9C2DW,?
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一、基础 C`LHFqv
1、说明:创建数据库 6o4Bf| E]
CREATE DATABASE database-name zEYT,l
2、说明:删除数据库 m/(f?M l
drop database dbname "fTW2D74
3、说明:备份sql server Y3RaR
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--- 创建 备份数据的 device u^Sa{Jk=
USE master TCI%Ox|a
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' x%d\}%]
--- 开始 备份 K~DQUmU@
BACKUP DATABASE pubs TO testBack RAps`)OR?
4、说明:创建新表 ZN `D!e6
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) y>YQx\mK
根据已有的表创建新表: +J<igb!S
A:create table tab_new like tab_old (使用旧表创建新表) OPtFz6
B:create table tab_new as select col1,col2... from tab_old definition only -0o1iU7
5、说明:删除新表 K.T.?ug;:
drop table tabname Ns}BE H
6、说明:增加一个列 #Z)8,N
Alter table tabname add column col type 6<
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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。 'W2B**}
7、说明:添加主键: Alter table tabname add primary key(col) mufJ@Y S#
说明:删除主键: Alter table tabname drop primary key(col) 2Sg^SZFH+o
8、说明:创建索引:create [unique] index idxname on tabname(col....) gfY1:0
删除索引:drop index idxname ,6iXl ch
注:索引是不可更改的,想更改必须删除重新建。 `1fNB1c
9、说明:创建视图:create view viewname as select statement [W#M(`}D
删除视图:drop view viewname g&<3Kl
10、说明:几个简单的基本的sql语句 S_ELV#X
选择:select * from table1 where 范围 c> }fy
插入:insert into table1(field1,field2) values(value1,value2) <<5x"W(,
删除:delete from table1 where 范围 e"@Ag:r@a
更新:update table1 set field1=value1 where 范围 M8p6f)l3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! V9dJNt'Ui
排序:select * from table1 order by field1,field2 [desc] '1r<g\l
总数:select count as totalcount from table1 jM%8h$&E
求和:select sum(field1) as sumvalue from table1 de<T5/
平均:select avg(field1) as avgvalue from table1 9iy3 dy^
最大:select max(field1) as maxvalue from table1 .WV5Gf)
最小:select min(field1) as minvalue from table1 CL)*cu6zG
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11、说明:几个高级查询运算词 4?2$~\
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A: UNION 运算符 4/J"}S
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。 (aTpBXGr=
B: EXCEPT 运算符 7(W"NF{r
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。 -D&d1`N4
C: INTERSECT 运算符 $FM:8^
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 Mr6 q7
注:使用运算词的几个查询结果行必须是一致的。 ucwUeRw,
12、说明:使用外连接 "t!_bma
A、left outer join: J7Y lmi
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 !0DOj["
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W0qn$H
B:right outer join: Hph$Z1{
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 > %B7/l$
C:full outer join: cf{rK`Ff^
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}x&A^$
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二、提升 xwjiNJ Gj
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) t[=teB v<
法一:select * into b from a where 1<>1 ;cD&qheDV
法二:select top 0 * into b from a YU6D;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) JuM4Njz|
insert into b(a, b, c) select d,e,f from b; l1uv]t <
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) >Nr~7s
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mF`%Z~}b
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -?Kd[Ma
4、说明:子查询(表名1:a 表名2:b) Cak-J~=
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) Zg;%$ kSQ
5、说明:显示文章、提交人和最后回复时间 =OR"Bd:O
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b t=BXuFiu
6、说明:外连接查询(表名1:a 表名2:b) s.j6"
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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 ) =Eb4Iyz
select * from (SELECT a,b,c FROM a) T where t.a > 1; s_RUb
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 O&@pi-=o
select * from table1 where time between time1 and time2 w3E#v&"=Y
select a,b,c, from table1 where a not between 数值1 and 数值2 L/*K4xQ
9、说明:in 的使用方法 q)QM+4
select * from table1 where a [not] in ('值1','值2','值4','值6') H*R4A E0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /P
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) o%_Hmd;_'
11、说明:四表联查问题: SsfHp
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 ..... \@F~4,VT
12、说明:日程安排提前五分钟提醒 i{2ny$55h
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 eccJt
13、说明:一条sql 语句搞定数据库分页 G/y;o3/[Z
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Ro:)N:C
14、说明:前10条记录 {}DoRpq=
select top 10 * form table1 where 范围 ujan2'YT
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Qoom[@$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) bv9nDNPD4
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 r";;Fk#5
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4B$|UG
17、说明:随机取出10条数据 ~Sc{\ZJl
select top 10 * from tablename order by newid() #2*6esP
18、说明:随机选择记录 cu )w6!f
select newid() cVuT|b^
19、说明:删除重复记录 {2=f,,|+f
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) r9y(j
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20、说明:列出数据库里所有的表名 NGL,j\(~7
select name from sysobjects where type='U' +XoY@|Djd
21、说明:列出表里的所有的 7x//4G
select name from syscolumns where id=object_id('TableName') o3,}X@p
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。 .)[0yW&
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 :O/QgGZN$
显示结果: n?}7vz;
type vender pcs {2T;^+KE
电脑 A 1 j:P(,M[
电脑 A 1 R>y/Y<5=
光盘 B 2 <Oihwr@5<
光盘 A 2 b<8,'QgB
手机 B 3 D]NJ^.X
手机 C 3 x't@Mc
23、说明:初始化表table1 v/[*Pze,C
TRUNCATE TABLE table1 cllnYvr3
24、说明:选择从10到15的记录 2f0qfF
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?G<.W[3
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三、技巧 RhD
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, I~)A!vp
如: (g3@3.Kk)
if @strWhere !='' fX{Xw0
begin -s&7zqW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *_H^]wNJG
end x9 i^_3Z
else ,&iZ*6=X?0
begin s7"5NU-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' tf4clzSTa
end > K s.
我们可以直接写成 *yqke<o9)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere bBgyLyg
2、收缩数据库 -fT}Nj\
--重建索引 w"
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DBCC REINDEX 3='Kii=LA
DBCC INDEXDEFRAG ra}t#Xt`
--收缩数据和日志 8Az|SJ<
DBCC SHRINKDB 1a_;(T
DBCC SHRINKFILE Ws;X;7tS
3、压缩数据库 ]/{iIS_
dbcc shrinkdatabase(dbname) ~*hCTqHvN
4、转移数据库给新用户以已存在用户权限 Wiere0 2*
exec sp_change_users_login 'update_one','newname','oldname' sfzDE&>'
go {-1N@*K
5、检查备份集 q]#j,}cN9
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3T~DeqAyw
6、修复数据库 3,)[Q?nKD
ALTER DATABASE [dvbbs] SET SINGLE_USER =?[:Nj636
GO >oL| nwn
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK oq[r+E-]$@
GO Z. ,pcnaQb
ALTER DATABASE [dvbbs] SET MULTI_USER BE)&.}l
GO u]sxX")
7、日志清除 %hi]oz
SET NOCOUNT ON o,[Em<
DECLARE @LogicalFileName sysname, 4P}d/w?'KL
@MaxMinutes INT, b]g#mQ
@NewSize INT :4[_&]H
USE tablename -- 要操作的数据库名 6 jU?~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 OXS.CFZM
@MaxMinutes = 10, -- Limit on time allowed to wrap log. cS(=wC
@NewSize = 1 -- 你想设定的日志文件的大小(M) 'tJxADK
-- Setup / initialize Xa_:B\ic
DECLARE @OriginalSize int 3u/ GrsF
SELECT @OriginalSize = size %|B$y;q^3
FROM sysfiles Zx^R -9
WHERE name = @LogicalFileName (o4':/es
SELECT 'Original Size of ' + db_name() + ' LOG is ' + =55V<VI
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + IAMtMO^L
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' qAi:F=> X
FROM sysfiles dpcU`$kt
WHERE name = @LogicalFileName X3HJ3F;==
CREATE TABLE DummyTrans wowWq\euY
(DummyColumn char (8000) not null) ?I"FmJ;
DECLARE @Counter INT, ~(]'ah,
@StartTime DATETIME, EOXuc9>G
@TruncLog VARCHAR(255) t(1gJZs>kX
SELECT @StartTime = GETDATE(), J3hhh(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' th}&|Y)T2
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;i!$rL
EXEC (@TruncLog) |y&vMx~t
-- Wrap the log if necessary. lcXo>
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired aB{OXU}#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _mTNK^gB
AND (@OriginalSize * 8 /1024) > @NewSize wcW7k(+0
BEGIN -- Outer loop. d(^3S>V|q
SELECT @Counter = 0 `d4;T|f+=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ro8C^d]
BEGIN -- update !eP0b~$/^J
INSERT DummyTrans VALUES ('Fill Log') >nO[5
DELETE DummyTrans /4$ c-k
SELECT @Counter = @Counter + 1 ]CX^!n
END M$e$%kPShE
EXEC (@TruncLog) irMBd8WG
END ge#P(Itz
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Sg1,9[pb
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + tR(L>ZG{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' wsgT`M'J[
FROM sysfiles l"%WXi"X
WHERE name = @LogicalFileName 0aGAF ]
DROP TABLE DummyTrans Mo\nY5
SET NOCOUNT OFF -Fc 9mv(H
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' S"/gZfxer
9、存储更改全部表 zLg_0r*h1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =Ds&ArG
@OldOwner as NVARCHAR(128), qWJap-hb
@NewOwner as NVARCHAR(128) .jl^"{@6
AS BJjx y0+
DECLARE @Name as NVARCHAR(128) (, $Lp0mB7
DECLARE @Owner as NVARCHAR(128) N@8tf@BT
DECLARE @OwnerName as NVARCHAR(128) n"<'F4r
DECLARE curObject CURSOR FOR rLcXo%w
select 'Name' = name, 9g7Ok9dF
'Owner' = user_name(uid) 4|NcWpaV7
from sysobjects S9 @*g3
where user_name(uid)=@OldOwner `tm(3pJ
order by name 10*^
OPEN curObject <<6gsKP
FETCH NEXT FROM curObject INTO @Name, @Owner 8},fu3Z
WHILE(@@FETCH_STATUS=0) u43-\=1$T
BEGIN Yy_mX}\x
if @Owner=@OldOwner 4}Hf"L[ l
begin -;$jo-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) aq8mD^j -&
exec sp_changeobjectowner @OwnerName, @NewOwner uR82},r$m
end [H>/N7v19*
-- select @name,@NewOwner,@OldOwner 8\[qR_LV
FETCH NEXT FROM curObject INTO @Name, @Owner @@|H8mP}H
END N}q*(r!q<
close curObject !DeU8.%
deallocate curObject ||.Ve,<:
GO b<KKF '
10、SQL SERVER中直接循环写入数据 }:+P{
declare @i int eb<'>a
set @i=1 T7Yg^ -"
while @i<30 !}HT&N8[r
begin h3;RVtS
insert into test (userid) values(@i) Yq:TWeZD
set @i=@i+1 62#8c~dL
end #K/#-S
小记存储过程中经常用到的本周,本月,本年函数 WI54xu1M
Dateadd(wk,datediff(wk,0,getdate()),-1) vo2 T P:
Dateadd(wk,datediff(wk,0,getdate()),6) =Lr#
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Dateadd(mm,datediff(mm,0,getdate()),0) sUsIu,1Q
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *.
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Dateadd(yy,datediff(yy,0,getdate()),0) mC84fss
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k!m9
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上面的SQL代码只是一个时间段 ~ph>?xuw
Dateadd(wk,datediff(wk,0,getdate()),-1) V$ac}A,!
Dateadd(wk,datediff(wk,0,getdate()),6) ~kPZh1n`
就是表示本周时间段. Zh.[f+ l]
下面的SQL的条件部分,就是查询时间段在本周范围内的: }L|XZL_Jo#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (+0yZ7AZ
而在存储过程中 !6d`e"\K
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 5K?%Eo72!=
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) M \3Zj(E/