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。 5Pc;5
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一、基础 ?>:g?.+
1、说明:创建数据库 5DU6rks%
CREATE DATABASE database-name 1s&zMWC
2、说明:删除数据库 rgQOj^xKv^
drop database dbname ?=msH=N<l
3、说明:备份sql server "S]0
--- 创建 备份数据的 device )r?}P1J7
USE master xj)F55e?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ($MlX BI
--- 开始 备份 }"H,h)T
BACKUP DATABASE pubs TO testBack C==hox7b
4、说明:创建新表 ?4} h&/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) a5^]20Fa
根据已有的表创建新表: Y5Bo|*b
A:create table tab_new like tab_old (使用旧表创建新表) p`dU2gV
B:create table tab_new as select col1,col2... from tab_old definition only ys^oG$lq
5、说明:删除新表 |^I0dR/w:
drop table tabname 2,oKVm+
6、说明:增加一个列 7F7{)L
Alter table tabname add column col type ?!:ha;n
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。 (,\+tr8r8
7、说明:添加主键: Alter table tabname add primary key(col) UgSB>V<?
说明:删除主键: Alter table tabname drop primary key(col) ?3,:-"(@p
8、说明:创建索引:create [unique] index idxname on tabname(col....) )EuvRLo{S7
删除索引:drop index idxname -Cpl?Io`r5
注:索引是不可更改的,想更改必须删除重新建。 f}ji?p
9、说明:创建视图:create view viewname as select statement {4}yKjW%z
删除视图:drop view viewname `AtBtjs RV
10、说明:几个简单的基本的sql语句 [!uG1 GJ>
选择:select * from table1 where 范围 4B1v4g8}
插入:insert into table1(field1,field2) values(value1,value2) *%NT~C
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删除:delete from table1 where 范围 D/xbF`
更新:update table1 set field1=value1 where 范围 ?
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! n
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排序:select * from table1 order by field1,field2 [desc] xh,qNnGGi
总数:select count as totalcount from table1 KP^V>9q
求和:select sum(field1) as sumvalue from table1 @})|Z}~
平均:select avg(field1) as avgvalue from table1 J?1 uKR
最大:select max(field1) as maxvalue from table1 #U4F0BdA
最小:select min(field1) as minvalue from table1 YUD`!C
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11、说明:几个高级查询运算词 ZohCP
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A: UNION 运算符 L(<*)No
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。 B\=8_z
B: EXCEPT 运算符 %#:{UR)E
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。 drP=A~?&:
C: INTERSECT 运算符 ~9]hV7y5C
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。 jl$ece5v
注:使用运算词的几个查询结果行必须是一致的。 py!|\00}
12、说明:使用外连接 ~d4 )/y
A、left outer join: QB uMJm
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。 Xm}/0g&7
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 ~O0 $Suv
B:right outer join: }Yzco52
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。 HY*Kb+[
C:full outer join: H3^},.
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。 H>IMf/%5N-
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二、提升 61>.vT8P
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) vhW2PzHFRi
法一:select * into b from a where 1<>1 F=e8 IUr
法二:select top 0 * into b from a HGs $*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) NZLxHD]mp
insert into b(a, b, c) select d,e,f from b; 9igiZmM
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) s}9S8@#
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 L-WT]&n_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. x(6SG+Kr
4、说明:子查询(表名1:a 表名2:b) Ts[_u@
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) wPd3F.<$
5、说明:显示文章、提交人和最后回复时间 ^R7lom.
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %KhI>O<
6、说明:外连接查询(表名1:a 表名2:b) W0@n/U
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c x7&B$.>3
7、说明:在线视图查询(表名1:a ) H9`)BbR
select * from (SELECT a,b,c FROM a) T where t.a > 1; EzM
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 {0wIR_dGX
select * from table1 where time between time1 and time2 JV^=v@Z3
select a,b,c, from table1 where a not between 数值1 and 数值2 xQ-<WF1i
9、说明:in 的使用方法 vjGo;+K
select * from table1 where a [not] in ('值1','值2','值4','值6') q]ku5A\y
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @sW24J1q+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _LEK%
11、说明:四表联查问题: XFHYQ2ME2
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... nLZTK&7}
12、说明:日程安排提前五分钟提醒 |P
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 QC
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13、说明:一条sql 语句搞定数据库分页 7hD>As7`/
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 TCwFPlF|
14、说明:前10条记录 en4k/w_
select top 10 * form table1 where 范围 A@!qv#'
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 'j8:vq^d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) HSE!x_$
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 '6iEMg&3
(select a from tableA ) except (select a from tableB) except (select a from tableC) YW,tCtI0_
17、说明:随机取出10条数据 %op**@4/t\
select top 10 * from tablename order by newid() )Pa'UGY
18、说明:随机选择记录 b7?uq9
select newid() >reU#j
19、说明:删除重复记录 z;,u}u}aI
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) shy-Gu&
20、说明:列出数据库里所有的表名 ,*TmIPNK
select name from sysobjects where type='U' F4-$~v@
21、说明:列出表里的所有的 hB]Np1('
select name from syscolumns where id=object_id('TableName') i4Q@K,$
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。 j|DsG,
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 <SAzxo:I
显示结果: a8e6H30Sm
type vender pcs E!)xj.aS$
电脑 A 1 5K1)1E/Fu
电脑 A 1 ntX3Nt_n
光盘 B 2 Af~$TyX
光盘 A 2 twHVv
手机 B 3 A7Cm5>Y_S
手机 C 3 >UTBO|95y
23、说明:初始化表table1 Wq D4YGN
TRUNCATE TABLE table1 "rALt~AX
24、说明:选择从10到15的记录 Z!a=dnwHz
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc T[w]o}>cW
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三、技巧 )Yh+c=6
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1、1=1,1=2的使用,在SQL语句组合时用的较多 )
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, z3{G9Np
如: K-^\"
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if @strWhere !='' ]NQfX[
begin : %_LpZ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;>U2|>5V
end zJKv'>?
else ]!W=^!
begin "b~+;<}Q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b"<liGh"n-
end ^
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我们可以直接写成 ,1.p%UE]>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4B8oO
2、收缩数据库 p}}R-D&K
--重建索引 n K1Slg#U
DBCC REINDEX _b
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DBCC INDEXDEFRAG =g7x'
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--收缩数据和日志 IkL#SgY
DBCC SHRINKDB CCs%%U/=
DBCC SHRINKFILE ch*8B(:
3、压缩数据库 t5^{D>S1
dbcc shrinkdatabase(dbname) OR P\b
4、转移数据库给新用户以已存在用户权限 3,_aAgeE
exec sp_change_users_login 'update_one','newname','oldname' ].avItg
go 5ORo3T%
5、检查备份集 f=+mIZ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9 &dtd
6、修复数据库 2"v6
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ALTER DATABASE [dvbbs] SET SINGLE_USER /cUO$m o
GO aL\PGdgO
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~gJwW+
GO etQCzYIhn
ALTER DATABASE [dvbbs] SET MULTI_USER ~p6 V,Q
GO ~Py`P'+
7、日志清除 pHGYQ;:L
SET NOCOUNT ON R3f89
DECLARE @LogicalFileName sysname, w?PkO p
@MaxMinutes INT, $j%'{)gK
@NewSize INT #"6Qj'/h
USE tablename -- 要操作的数据库名 df8k7D;~e
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 u= *FI
@MaxMinutes = 10, -- Limit on time allowed to wrap log. etDk35!h~,
@NewSize = 1 -- 你想设定的日志文件的大小(M) L tO!umM
-- Setup / initialize (Bb5?fw
DECLARE @OriginalSize int Pjf"CW+A
SELECT @OriginalSize = size vQG5*pR*w
FROM sysfiles zy?|ODM
WHERE name = @LogicalFileName V;VHv=9`o
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 88O8wJN
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Lz}OwKl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' BGZ#wru
FROM sysfiles D(op)]8
WHERE name = @LogicalFileName c%
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CREATE TABLE DummyTrans #b}Z`u?@
(DummyColumn char (8000) not null) H\" sgoJ
DECLARE @Counter INT, |)th1
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@StartTime DATETIME, _#E0g'3
@TruncLog VARCHAR(255) 3PWL@>zi
SELECT @StartTime = GETDATE(), "m$##X\
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %bn jgy
DBCC SHRINKFILE (@LogicalFileName, @NewSize) IJp-BTO{V
EXEC (@TruncLog) nIf1sH>
-- Wrap the log if necessary. 7vKK%H_P
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired wc@X.Q[
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) pZ{+c
AND (@OriginalSize * 8 /1024) > @NewSize ij`w} V
BEGIN -- Outer loop. e;q!6%
SELECT @Counter = 0 )gUR@V>e2
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) vkV0On
BEGIN -- update LKB$,pR~1l
INSERT DummyTrans VALUES ('Fill Log') Xf]d. :
DELETE DummyTrans
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SELECT @Counter = @Counter + 1 oG?Xk%7&\
END @CL{D:d
EXEC (@TruncLog) r.&Vw|*>
END Yx%Hs5}8
SELECT 'Final Size of ' + db_name() + ' LOG is ' + B)g[3gQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + z (wc0I
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^98~U\ar
FROM sysfiles 7hcYD!DS
WHERE name = @LogicalFileName 2 c{34:
DROP TABLE DummyTrans 20 h, ^
SET NOCOUNT OFF 9G5rcYi
8、说明:更改某个表 :J@gmY:C
exec sp_changeobjectowner 'tablename','dbo' L|7R9+ZG
9、存储更改全部表 z'n:@E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g3/W=~r
@OldOwner as NVARCHAR(128), 6,"Q=9k4[
@NewOwner as NVARCHAR(128) U(g:zae
AS E7UU
DECLARE @Name as NVARCHAR(128) }B+C~@j
DECLARE @Owner as NVARCHAR(128) ;bib/
DECLARE @OwnerName as NVARCHAR(128) P
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DECLARE curObject CURSOR FOR }<SQ
select 'Name' = name, 5L%'@`mX
'Owner' = user_name(uid) Ya"a`ozq
from sysobjects /nNN,hz
where user_name(uid)=@OldOwner }q`S$P;
order by name S`0(*A[W*
OPEN curObject WPMSm<[
FETCH NEXT FROM curObject INTO @Name, @Owner 9}<ile7^
WHILE(@@FETCH_STATUS=0) d.d/<
BEGIN 06Sceq
if @Owner=@OldOwner P@Oo$ o
begin [D4SW#
set @OwnerName = @OldOwner + '.' + rtrim(@Name) cf20.F{<
exec sp_changeobjectowner @OwnerName, @NewOwner f+,qNvBY/
end w``ST
-- select @name,@NewOwner,@OldOwner m@v\(rT.
FETCH NEXT FROM curObject INTO @Name, @Owner N
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END SsDmoEeB[
close curObject MaQqs=
deallocate curObject
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GO #a,PZDaE
10、SQL SERVER中直接循环写入数据 K;H&n1
declare @i int _9Te!gJ4_#
set @i=1 ~-Qw.EdC
while @i<30 ,m|h<faZL
begin ^%{7}g&$u
insert into test (userid) values(@i) plstZ,#j
set @i=@i+1 0-Ku7<a
end uh>; 8
小记存储过程中经常用到的本周,本月,本年函数 LCKV>3+_#
Dateadd(wk,datediff(wk,0,getdate()),-1) ]Q3ADh
Dateadd(wk,datediff(wk,0,getdate()),6) :{l_FY436
Dateadd(mm,datediff(mm,0,getdate()),0) Jk
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) s-Tv8goNV
Dateadd(yy,datediff(yy,0,getdate()),0) wc4{)qDE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) HBXOjr<,{
上面的SQL代码只是一个时间段 mNTzUoZF'@
Dateadd(wk,datediff(wk,0,getdate()),-1) ;$wVu|&
Dateadd(wk,datediff(wk,0,getdate()),6) nMUw_7Y6
就是表示本周时间段. :OT0yA=U
下面的SQL的条件部分,就是查询时间段在本周范围内的: `dN@u@[\ks
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &@OT*pNna
而在存储过程中 _Q 4)X)F
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 0~/_|?]`7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &n:.k}/P