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。 q},,[t
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一、基础 9
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1、说明:创建数据库 "fv+}'
CREATE DATABASE database-name mHW%^R=
2、说明:删除数据库 x]hG2on!
drop database dbname 0n4( Rj|}2
3、说明:备份sql server b^<7a&
--- 创建 备份数据的 device !"/"Mqs3$
USE master Zw4%L?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' pHoxw|'Y
--- 开始 备份 FeZW S>N
BACKUP DATABASE pubs TO testBack {C?$osrr
4、说明:创建新表 jC:D>
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) N0$
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根据已有的表创建新表: dj9i*#F
A:create table tab_new like tab_old (使用旧表创建新表) uk WL3
B:create table tab_new as select col1,col2... from tab_old definition only ;[Xf@xf
5、说明:删除新表 9X1vL
drop table tabname .#sX|c=W
6、说明:增加一个列 I)jAdd
Alter table tabname add column col type 8?'=Aeo
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。 $z)egh(z
7、说明:添加主键: Alter table tabname add primary key(col) >(YH@Z&;
说明:删除主键: Alter table tabname drop primary key(col) "p+oi@
8、说明:创建索引:create [unique] index idxname on tabname(col....) iM9k!u FE
删除索引:drop index idxname xrY >Or
注:索引是不可更改的,想更改必须删除重新建。 T^+K`U
9、说明:创建视图:create view viewname as select statement >e.vUUQ{
删除视图:drop view viewname yXtQfR
10、说明:几个简单的基本的sql语句 6
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选择:select * from table1 where 范围 ;InMgo,
插入:insert into table1(field1,field2) values(value1,value2) FB,rQ9D
删除:delete from table1 where 范围 s/>0gu]A8
更新:update table1 set field1=value1 where 范围 ./DlHS;
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6W]C`
排序:select * from table1 order by field1,field2 [desc] v^t oe
总数:select count as totalcount from table1 #ax% n
求和:select sum(field1) as sumvalue from table1 )eSQce7H
平均:select avg(field1) as avgvalue from table1 dci,[TEGu
最大:select max(field1) as maxvalue from table1 ?qHQ#0 @y]
最小:select min(field1) as minvalue from table1 =<#++;!I
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11、说明:几个高级查询运算词 X?u=R)uG
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A: UNION 运算符 Xfb-<
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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。 i8cmT+}>
B: EXCEPT 运算符 I3Z\]BI
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。 @3b @]l5
C: INTERSECT 运算符 %/nDG9l
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。 K'E)?NW69
注:使用运算词的几个查询结果行必须是一致的。 EN}4-P/5
12、说明:使用外连接 G:|]w,^i
A、left outer join: 8WQc8
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。 -m=!SQ >9
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 aAd1[?&
B:right outer join: DtS7)/<T
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。 I+^iOa
C:full outer join: 3T 0'zJ2f
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。 /UR;,ts
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二、提升 S;#7B?j
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !-SI &qy
法一:select * into b from a where 1<>1 ?caHS2%?ae
法二:select top 0 * into b from a Kxh WZ3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) UpQda`rb
insert into b(a, b, c) select d,e,f from b; cV`NQt <W
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) Ya<V@qd
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,k@iNid
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) ?<
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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) |Zo36@s
5、说明:显示文章、提交人和最后回复时间 LZ(K{+U/
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'c/8|9jX
6、说明:外连接查询(表名1:a 表名2:b) M3d%$q)<rW
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )*.rl
7、说明:在线视图查询(表名1:a ) ]haQ#e}WH
select * from (SELECT a,b,c FROM a) T where t.a > 1; '['x'G50
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>b{hkIXg
select * from table1 where time between time1 and time2 931GJA~g
select a,b,c, from table1 where a not between 数值1 and 数值2 o~xGE 6A*"
9、说明:in 的使用方法 d,'gh4C
select * from table1 where a [not] in ('值1','值2','值4','值6') J-klpr#
10、说明:两张关联表,删除主表中已经在副表中没有的信息 x],XiSyp
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) BoARM{m
11、说明:四表联查问题: 80gOh:
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 ..... r#}o
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12、说明:日程安排提前五分钟提醒 =
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 u<Ch]m+
13、说明:一条sql 语句搞定数据库分页 _3g!_
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 7#N= GN
14、说明:前10条记录 GbkDs-
select top 10 * form table1 where 范围 VhnIr#L+
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.) (II#9n)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) OwDwa~
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 (enOj0
(select a from tableA ) except (select a from tableB) except (select a from tableC) %bG\
17、说明:随机取出10条数据 anKflt3
select top 10 * from tablename order by newid() ?ZhBS3L
18、说明:随机选择记录 TOvsW<cM
select newid() `Xi)';p
19、说明:删除重复记录 bXM&VW?OP
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \4fuC6d2
20、说明:列出数据库里所有的表名 :"i2`y;u
select name from sysobjects where type='U' i8*(J-M
21、说明:列出表里的所有的 ^7:UC\_
select name from syscolumns where id=object_id('TableName') B'PS-Jr
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。 T#H-GOY:
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 ^%U`|GBZp
显示结果: +t]Ge
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type vender pcs J'I1NeK
电脑 A 1 p7.~k1h
电脑 A 1 pQ ul0]
光盘 B 2 'OU3-K
光盘 A 2 :$XlYJrjK
手机 B 3 -<u_fv
手机 C 3 DoN]v
23、说明:初始化表table1 #,"[sag
TRUNCATE TABLE table1 u0Z MrIJ
24、说明:选择从10到15的记录 6OtNWbB
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *m'&<pg]X
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三、技巧 {yxLL-5c
1、1=1,1=2的使用,在SQL语句组合时用的较多 oy=ej+:
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +R8dy
如: 16~5 ;u
if @strWhere !='' xaq/L:I<
begin ?. L]QU
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere TyR@3H
end & TN.6Hm3
else 4dI`
begin b>}
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i\K88B&24
end cA90FqUH
我们可以直接写成 Yqt~h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Yic4|N?u
2、收缩数据库 (;N#Gqb6l
--重建索引 =ATQ2\T$m
DBCC REINDEX \MAv's4b@
DBCC INDEXDEFRAG {Q^ -
--收缩数据和日志 83)m#
DBCC SHRINKDB 6>b#nFVJ
DBCC SHRINKFILE sei%QE]!/
3、压缩数据库 #A<
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dbcc shrinkdatabase(dbname) Iqj?wI1)
4、转移数据库给新用户以已存在用户权限 @k-GyV-v
exec sp_change_users_login 'update_one','newname','oldname' ,K.Wni#m
go |A=~aQot
5、检查备份集 JUq7R%"h6
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T I yHM1+
6、修复数据库 Ozsvsa
ALTER DATABASE [dvbbs] SET SINGLE_USER AG Gxx?I
GO W7\UZPs5t
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NMN&mJsmh
GO \rH0=~F-P
ALTER DATABASE [dvbbs] SET MULTI_USER aMxM3"
GO ABq#I'H#@2
7、日志清除 Ou|kb61zg
SET NOCOUNT ON uPb. uG
DECLARE @LogicalFileName sysname, r;"Qu
@MaxMinutes INT, Zo Ra^o
@NewSize INT hXc:y0
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USE tablename -- 要操作的数据库名 Bv7os3xb
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 fz+dOIU3\L
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )qD V3
@NewSize = 1 -- 你想设定的日志文件的大小(M) 6ziBGU#.-
-- Setup / initialize fV!~SX6S
DECLARE @OriginalSize int ?]_A~_J!
SELECT @OriginalSize = size - G=doP0
FROM sysfiles U@}P]'`'f
WHERE name = @LogicalFileName `mS0]/AV/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + K[q-[q#yc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + PD^Cj?wm
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ztC,[
FROM sysfiles tSTl#xy
WHERE name = @LogicalFileName 8`|Z9umW*
CREATE TABLE DummyTrans /!hxW}>^
(DummyColumn char (8000) not null) f!B\X*|
DECLARE @Counter INT, aOmQ<N]a
@StartTime DATETIME, aM\Ph&c7e'
@TruncLog VARCHAR(255) |O*?[|`H
SELECT @StartTime = GETDATE(), 5^N`~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' WG&WPV/p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) u)Vn7zh
EXEC (@TruncLog) X/D%
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-- Wrap the log if necessary. NLev(B:OQH
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired O7f"8|=HX
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *3y_FTh8ra
AND (@OriginalSize * 8 /1024) > @NewSize H<l0]-S{
BEGIN -- Outer loop. ?|GwuG8g
SELECT @Counter = 0 0)9n${P7d
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $$T a
BEGIN -- update tG0
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INSERT DummyTrans VALUES ('Fill Log') "l(<<Ha/
DELETE DummyTrans LiJ. /
SELECT @Counter = @Counter + 1 1@q"rPE^
END fs,>X!l+
EXEC (@TruncLog) zy8D&7Ytf
END EV
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + T?{F7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + i >BQRbU
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' wHs4~"EY9
FROM sysfiles @-O%u*%J
WHERE name = @LogicalFileName or[! C%
DROP TABLE DummyTrans 2'}/aL|G
SET NOCOUNT OFF 41i#w;ojI
8、说明:更改某个表 z[]8"C=
exec sp_changeobjectowner 'tablename','dbo' 3o_@3-Y%
9、存储更改全部表 .R&jRtb/E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch n-CFB:L
@OldOwner as NVARCHAR(128), Z07SK 'U
@NewOwner as NVARCHAR(128) cXt]55"
AS TcH7!fUj
DECLARE @Name as NVARCHAR(128) }t1J`+x%
DECLARE @Owner as NVARCHAR(128) Qt=OiKZ
DECLARE @OwnerName as NVARCHAR(128) W'Y#(N[ktP
DECLARE curObject CURSOR FOR 9gETWz(3I
select 'Name' = name, A3Vj3em
'Owner' = user_name(uid)
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from sysobjects gzp]hh@4
where user_name(uid)=@OldOwner GAlM:>
order by name b2hXFwPe
OPEN curObject lkb,UL;V
FETCH NEXT FROM curObject INTO @Name, @Owner h?vt6t9
WHILE(@@FETCH_STATUS=0) FivqyT7i
BEGIN |p*s:*TJp
if @Owner=@OldOwner #mRT>]di`D
begin ]mx1djNA
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e Y(JU5{
exec sp_changeobjectowner @OwnerName, @NewOwner v@qVT'qlU
end K^c%$n:}+
-- select @name,@NewOwner,@OldOwner x#'v}(v
FETCH NEXT FROM curObject INTO @Name, @Owner G@,XUP
END =u.hHkx
close curObject Ym9~/'%]
deallocate curObject _[y<u})
GO (6i.>%|_
10、SQL SERVER中直接循环写入数据 =la~D]T*g
declare @i int @5cY5e*i{
set @i=1 fh9w5hT={
while @i<30 dz)(~@tgz
begin 4R9y~~+
insert into test (userid) values(@i) +<sv/gEt
set @i=@i+1 Vd A!tL
end q) y<\cEO
小记存储过程中经常用到的本周,本月,本年函数 e^-CxHwA-
Dateadd(wk,datediff(wk,0,getdate()),-1) ~L9I@(/S
Dateadd(wk,datediff(wk,0,getdate()),6) LbnW(wr6:(
Dateadd(mm,datediff(mm,0,getdate()),0) Gg{M
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) OsgjSJrf
Dateadd(yy,datediff(yy,0,getdate()),0) {0\9HI@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) jR^_1bu
上面的SQL代码只是一个时间段 1-8G2e
Dateadd(wk,datediff(wk,0,getdate()),-1) US]I[Y6V
Dateadd(wk,datediff(wk,0,getdate()),6) yzyK$WN\[3
就是表示本周时间段. -~^sSLrbP
下面的SQL的条件部分,就是查询时间段在本周范围内的: g<YN#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Jmun^Q/h
而在存储过程中 8g3?@i
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1W{t?1[s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) R-1C#R[