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。 ZmP1C`>
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一、基础 C#T)@UxBZ
1、说明:创建数据库 4V>vg2
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CREATE DATABASE database-name <L%HG
2、说明:删除数据库 !,R
drop database dbname 8z0Hx
3、说明:备份sql server /t5g"n3
--- 创建 备份数据的 device 9?!u2 o
USE master F*.
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \CDAFu#
--- 开始 备份 P 4H*jy@?
BACKUP DATABASE pubs TO testBack `43vxcMg
4、说明:创建新表 uzO{{S-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) % dYI5U89
根据已有的表创建新表: k|fh\F+$
A:create table tab_new like tab_old (使用旧表创建新表) Q>V?w gZ
B:create table tab_new as select col1,col2... from tab_old definition only VAt>ji7c
5、说明:删除新表 TftOYY.hQ
drop table tabname i(z+a6^@|
6、说明:增加一个列 iPz1eUj
Alter table tabname add column col type R'r|E_
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。 R rxRa[{Z
7、说明:添加主键: Alter table tabname add primary key(col) @_(nd57oSs
说明:删除主键: Alter table tabname drop primary key(col) 65uZLsQ
8、说明:创建索引:create [unique] index idxname on tabname(col....) -z&9DWH
删除索引:drop index idxname 83B\+]{hD
注:索引是不可更改的,想更改必须删除重新建。 v F]
9、说明:创建视图:create view viewname as select statement tI
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删除视图:drop view viewname 2"zI R(
10、说明:几个简单的基本的sql语句 0NVG"-Q
选择:select * from table1 where 范围 x}uwWfe 3
插入:insert into table1(field1,field2) values(value1,value2) E=A/4p6\$
删除:delete from table1 where 范围 ~xP
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更新:update table1 set field1=value1 where 范围 l#mtND3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ]}5`7
排序:select * from table1 order by field1,field2 [desc] Q-:Ah:/
总数:select count as totalcount from table1 *P&OxVz
求和:select sum(field1) as sumvalue from table1 +V6j`
平均:select avg(field1) as avgvalue from table1 rknzo]N,
最大:select max(field1) as maxvalue from table1 MG;4M>H
最小:select min(field1) as minvalue from table1 IM$'J
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11、说明:几个高级查询运算词 ozT._C
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A: UNION 运算符 >Zi|$@7t-
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。 K~P76jAe$
B: EXCEPT 运算符 HE9.
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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。 "MW55OWYU
C: INTERSECT 运算符 1LV|t+Sex
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。 >>/nuWdpO
注:使用运算词的几个查询结果行必须是一致的。 "sC$%D<oc
12、说明:使用外连接 \%Pma8&d
A、left outer join: _CHKh*KHML
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ;<86P3S
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,^Ex}Z
B:right outer join: ))c*_n
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 :Xb*m85y
C:full outer join: :/ ~):tM
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 v\J!yz
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二、提升
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) fN~8L}!l
法一:select * into b from a where 1<>1 ^w.k^U=B
法二:select top 0 * into b from a VG? yL2y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =9#i<te
insert into b(a, b, c) select d,e,f from b; T]5U_AI@
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Lx9hq7<
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,oy4V ^B&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. h;&&@5@lM
4、说明:子查询(表名1:a 表名2:b) i(dXA(p
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) B(HNB\3u
5、说明:显示文章、提交人和最后回复时间 ch%Q'DR_I)
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b u0<d2Y
6、说明:外连接查询(表名1:a 表名2:b) J+-,^8)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c K+(m'3`
7、说明:在线视图查询(表名1:a ) c`Lpqs`
select * from (SELECT a,b,c FROM a) T where t.a > 1; <h)deB+}
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 G:H(IA7Z
select * from table1 where time between time1 and time2 <e@I1iL37y
select a,b,c, from table1 where a not between 数值1 and 数值2 Ly@U\%.
9、说明:in 的使用方法 MZgmv
select * from table1 where a [not] in ('值1','值2','值4','值6') &Z#Vw.7U
10、说明:两张关联表,删除主表中已经在副表中没有的信息 I$rW[l2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) "i;*\+x
11、说明:四表联查问题: &e5^v
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 ..... oXu~9'm$
12、说明:日程安排提前五分钟提醒 p?EEox
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 y}.y,\S0
13、说明:一条sql 语句搞定数据库分页 P#M<CG9
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 e!O &~#'h}
14、说明:前10条记录 (cbB%
select top 10 * form table1 where 范围 X7(rg W8
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.)
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 0nF>zOmc
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 lk5_s@V
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(select a from tableA ) except (select a from tableB) except (select a from tableC) oZ|{J
17、说明:随机取出10条数据 Xmw2$MCB
select top 10 * from tablename order by newid() J~ PTVR
18、说明:随机选择记录 0ll,V
select newid() B$iMU?B3
19、说明:删除重复记录 9}7oKlyk
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *R1d4|/G
20、说明:列出数据库里所有的表名 cHfK-R
select name from sysobjects where type='U' ]}*G[[
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21、说明:列出表里的所有的 +LvZ87O^~
select name from syscolumns where id=object_id('TableName') SV$ASs
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 < :S?t2C
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type r)*_,Fo|
显示结果: 3@#,i<ge :
type vender pcs -0[>}!l=G
电脑 A 1 n~L'icD[
电脑 A 1 [xH2n\7
光盘 B 2 &QHA_+88W
光盘 A 2 @=^jpSnZ
手机 B 3 #oS
手机 C 3 -F~9f>
23、说明:初始化表table1 #EwRb<'Em
TRUNCATE TABLE table1 }1E_G
24、说明:选择从10到15的记录 ]Y/pSwnV
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 8DmX4*
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三、技巧 wZ#~+ }T
1、1=1,1=2的使用,在SQL语句组合时用的较多 _'o^@v:
"where 1=1" 是表示选择全部 "where 1=2"全部不选, v:!7n
如: }pU!1GsO
if @strWhere !='' `^@g2c+d
begin 6 I>xd
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere h_}BmJ h_
end ?7uStqa
else YV>VA<c
begin ce-m)o/
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !3gpiQH{
end |Cxip&e>
我们可以直接写成 +=lcN~U2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere
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2、收缩数据库 L>K39z~,
--重建索引 n$Oky-P"
DBCC REINDEX ^~hhdwu3a
DBCC INDEXDEFRAG {yl/T:Bh&
--收缩数据和日志 `~s,W.Eu4
DBCC SHRINKDB 'FvhzGn9Q
DBCC SHRINKFILE %)!~t8To
3、压缩数据库 RI<Yg#
dbcc shrinkdatabase(dbname) ~P.-3
4、转移数据库给新用户以已存在用户权限 4h0jX9
exec sp_change_users_login 'update_one','newname','oldname' m0q`A5!)
go W.7d{
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5、检查备份集 ]((
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "#"Fp&Z7
6、修复数据库 e&VR>VJEA
ALTER DATABASE [dvbbs] SET SINGLE_USER ;gw!;!T
GO f%{ ag
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WG!;,~f>o
GO Tef3
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ALTER DATABASE [dvbbs] SET MULTI_USER ^?l-YnQqm?
GO "=0lcbC
7、日志清除 .$T:n[@
SET NOCOUNT ON lyc{Z%!3
DECLARE @LogicalFileName sysname, E6d8z=X(
@MaxMinutes INT, ^#6%*(D
@NewSize INT =Z$=-\<x0.
USE tablename -- 要操作的数据库名 kA9 X!)2w
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \Q
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. g{f>jd
@NewSize = 1 -- 你想设定的日志文件的大小(M) [OToz~=)
-- Setup / initialize HZ`G)1&)
DECLARE @OriginalSize int 5 <>agK]
SELECT @OriginalSize = size gpTF^.(
FROM sysfiles %2FCpre;
WHERE name = @LogicalFileName I}CA-8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0jx~_zq-j
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + fgz'C?
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' uvc{RP
FROM sysfiles <38@b
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WHERE name = @LogicalFileName 7ump:|
CREATE TABLE DummyTrans #j~FA3O
(DummyColumn char (8000) not null) jH#^O;A
DECLARE @Counter INT, N X#/1=
@StartTime DATETIME, 9G\3hL]
@TruncLog VARCHAR(255) b"3T(#2<*
SELECT @StartTime = GETDATE(), $5p'+bE
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' oVZ8p-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) @nW(KF
EXEC (@TruncLog)
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-- Wrap the log if necessary. %}AY0fg?T
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired V<R+A* gY:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~{tZ;YZ
AND (@OriginalSize * 8 /1024) > @NewSize >Ki]8&
BEGIN -- Outer loop. {w1h<;MH
SELECT @Counter = 0 It:QXLi;
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) f0`rJ?us
BEGIN -- update 5WNRo[`7
INSERT DummyTrans VALUES ('Fill Log') }\qdow-
DELETE DummyTrans o_^d>Klb8
SELECT @Counter = @Counter + 1 C36.UZoc
END aGkVC*T
EXEC (@TruncLog) 1H@rNam&
END )jZ=/xG
SELECT 'Final Size of ' + db_name() + ' LOG is ' + lM]),}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 'C8=d(mR=m
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #?d#s19s
FROM sysfiles 0GR9C%"]
WHERE name = @LogicalFileName <("w'd}
DROP TABLE DummyTrans s7cyo
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SET NOCOUNT OFF ~;4k UJD
8、说明:更改某个表 +W3>Yg%)X
exec sp_changeobjectowner 'tablename','dbo' B*?PB]
9、存储更改全部表 >+LgJo R
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch v\tbf
@OldOwner as NVARCHAR(128), 7 QJcRZ[lU
@NewOwner as NVARCHAR(128) :^L]Da3
AS SG o:FG
DECLARE @Name as NVARCHAR(128) uTt:/gm
DECLARE @Owner as NVARCHAR(128) 8qLgB
DECLARE @OwnerName as NVARCHAR(128) _+Kt=;Y8
DECLARE curObject CURSOR FOR 2 g8P$+;
select 'Name' = name, `G5wiyH})
'Owner' = user_name(uid) 6&Ir0K/
from sysobjects ]O `
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where user_name(uid)=@OldOwner P
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order by name <R8Z[H:bV
OPEN curObject 5K-)X9z?
FETCH NEXT FROM curObject INTO @Name, @Owner VYQbyD{V w
WHILE(@@FETCH_STATUS=0) ZVR 9vw28
BEGIN |dzF>8< )
if @Owner=@OldOwner tLXw&hFk`g
begin 6OW-Dif^AG
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ._nKM5.
exec sp_changeobjectowner @OwnerName, @NewOwner >o=p5#{
end EQhV}9
-- select @name,@NewOwner,@OldOwner #C7j|9Ew1]
FETCH NEXT FROM curObject INTO @Name, @Owner CXFAb1m
END !27]1%Aw
close curObject U:jf9L2
deallocate curObject h4i$z-!
GO ;i?!qB>baX
10、SQL SERVER中直接循环写入数据 TRok4uc
declare @i int `5&V}"lB
set @i=1 W)~.o/;
while @i<30 %$KO]
begin L=FvLii.
insert into test (userid) values(@i) *g6o ;c
set @i=@i+1 Bb"4^EOZ,
end v fDb9QP
小记存储过程中经常用到的本周,本月,本年函数 F}DD;K
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) <5}du9 @
Dateadd(mm,datediff(mm,0,getdate()),0) u@'zvkb@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) A+DYIS
Dateadd(yy,datediff(yy,0,getdate()),0) /~5YTe(F
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) jP'b! 4
上面的SQL代码只是一个时间段 E-iBA (H
Dateadd(wk,datediff(wk,0,getdate()),-1) x7@HPf
Dateadd(wk,datediff(wk,0,getdate()),6) ?zu{&aOX|
就是表示本周时间段. 28yxX431S
下面的SQL的条件部分,就是查询时间段在本周范围内的: AAY UXY!
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) y]%,Y=%X
而在存储过程中 9iNns;^`q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) F
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m3-J0D<