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。 ,;d9uG2
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一、基础 R-Fi`#PG2
1、说明:创建数据库 *>'R
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CREATE DATABASE database-name ABHZ)OM
2、说明:删除数据库 Lv^ j
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drop database dbname \7j)^
3、说明:备份sql server kxn;;
--- 创建 备份数据的 device qBNiuV;*
USE master `X^e}EGWu
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' YqJIp. Z
--- 开始 备份 Ez$5wY^J
BACKUP DATABASE pubs TO testBack n#&RY%#`
4、说明:创建新表 xRY5[=97
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) \QMSka>
根据已有的表创建新表: D1Sl+NOV
A:create table tab_new like tab_old (使用旧表创建新表) 'j3'n0o
B:create table tab_new as select col1,col2... from tab_old definition only P~qVr#eU
5、说明:删除新表 &"kx(B
drop table tabname 3QHZC0AY
6、说明:增加一个列 {PVu3W
Alter table tabname add column col type ]czy8n$+
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。 O^x t
7、说明:添加主键: Alter table tabname add primary key(col) nDOIE)#
说明:删除主键: Alter table tabname drop primary key(col) oPbD9
8、说明:创建索引:create [unique] index idxname on tabname(col....) rODKM-7+
删除索引:drop index idxname \fKE~61
注:索引是不可更改的,想更改必须删除重新建。 `P5"5N\h
9、说明:创建视图:create view viewname as select statement .~U9*5d
删除视图:drop view viewname LuqaGy}>-
10、说明:几个简单的基本的sql语句 IB6]Wj
选择:select * from table1 where 范围 ;?o C=c
插入:insert into table1(field1,field2) values(value1,value2) Kmnr}Lp9
删除:delete from table1 where 范围 K?tk&0
更新:update table1 set field1=value1 where 范围 p_AV3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $KKaA{0-
排序:select * from table1 order by field1,field2 [desc] Na6z,TW
总数:select count as totalcount from table1 :9YQX(l8
求和:select sum(field1) as sumvalue from table1 j%}Jl
平均:select avg(field1) as avgvalue from table1 )mPlB.
最大:select max(field1) as maxvalue from table1 -&EmEXs%
最小:select min(field1) as minvalue from table1 z )pV$
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11、说明:几个高级查询运算词 'oHR4O*
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A: UNION 运算符 =R'v]SXj
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。 =e;wEf%`
B: EXCEPT 运算符 uf^:3{1
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。 0|ps),
C: INTERSECT 运算符 ?},ItJ#>)q
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。 H+;wnI>@
注:使用运算词的几个查询结果行必须是一致的。 _5T7A><q<
12、说明:使用外连接 ^8m+*t
A、left outer join: (6BCFl:/Q<
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。 *e6|SZ &3
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
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B:right outer join: ]p!J]YV ]0
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。 6\3k0z
C:full outer join: [KH?5C
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。 DOerSh_0W
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二、提升 %&Cl@6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) QVW6SY
法一:select * into b from a where 1<>1 4iz&"~&1
法二:select top 0 * into b from a ]K7 64}
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用)
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insert into b(a, b, c) select d,e,f from b; =b7&(x
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) dNQSbp
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 B0i}Y-Z
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) gn"&/M9E
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) OQ7c|O
5、说明:显示文章、提交人和最后回复时间 'u[o`31.
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b sPg6eAd~?
6、说明:外连接查询(表名1:a 表名2:b) k^pu1g=6I
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Y/0O9}hf
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; $Jm2,Yv
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 6Qb)Uq3}]
select * from table1 where time between time1 and time2 u mlZ(??.
select a,b,c, from table1 where a not between 数值1 and 数值2 ikhX5
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9、说明:in 的使用方法 ku;nVV
select * from table1 where a [not] in ('值1','值2','值4','值6') l,u{:JC
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @'*#]YU8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) CLfb`rF
11、说明:四表联查问题: $-]setdY
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ^,K.)s
12、说明:日程安排提前五分钟提醒 d&bc>Vt
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Z]TVH8%|k
13、说明:一条sql 语句搞定数据库分页
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 LtztjAm.
14、说明:前10条记录 vB5iG|b}
select top 10 * form table1 where 范围 +&,\ J9'B
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) PAwg&._K
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6\Vu#r
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 MNqyEc""
(select a from tableA ) except (select a from tableB) except (select a from tableC) f#kevf9zc
17、说明:随机取出10条数据 ZYe\"|x,s
select top 10 * from tablename order by newid() pqN[G=0
18、说明:随机选择记录 uS#Cb+*F
select newid() )[sO5X7'^
19、说明:删除重复记录 {H;|G0tR
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) gVU\^KN]
20、说明:列出数据库里所有的表名 pMp9O/u%
select name from sysobjects where type='U' 3Z:!o$
21、说明:列出表里的所有的 [|n-x3h
select name from syscolumns where id=object_id('TableName') a<'$` z|s
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 R6Mxdm2P}
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type W 'a~pB1I
显示结果: 4sBoD=e
type vender pcs 0Eu$-)
电脑 A 1 f_h"gZWV
电脑 A 1 Z034wn\N
光盘 B 2 jL+}F /~r
光盘 A 2 'uACoME@
手机 B 3 0a6@HwO
手机 C 3 0^.4eX:E_
23、说明:初始化表table1 2{kfbm-89t
TRUNCATE TABLE table1 Gd6 ;'ZCmY
24、说明:选择从10到15的记录 \G=R hx f
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |C6(0fgWd
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三、技巧 7]xz8t
1、1=1,1=2的使用,在SQL语句组合时用的较多 qm8n7Z/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, C.)&FW2F_
如: Bb[e[,ah
if @strWhere !='' gDNTIOV
begin y2"S\%7$h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere z!C4>,
end G\>\VA
else +.#S[G
begin `J#xyDL6?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' l[ ": tG
end a]Da`$T
我们可以直接写成 uM)9b*Vbo
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere n+\Cw`'<H
2、收缩数据库 1X"H6j[w
--重建索引 ^$+f3Z'
DBCC REINDEX QGv:h[b_
DBCC INDEXDEFRAG ~q?"w:@;x
--收缩数据和日志 G'?f!fz;
DBCC SHRINKDB 7cmr
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DBCC SHRINKFILE ]7S7CVDk4
3、压缩数据库 , HI%Xn
dbcc shrinkdatabase(dbname) ym*#ZE`B!
4、转移数据库给新用户以已存在用户权限 Y0X94k.u
exec sp_change_users_login 'update_one','newname','oldname' W[X!P)=w]
go 5?{ >9j5
5、检查备份集 5@>4)dk\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *o e0=
6、修复数据库 w4fJ`,
ALTER DATABASE [dvbbs] SET SINGLE_USER &PBWJ?@O)r
GO a.}:d30
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4R*<WdT(
GO m wEVEx24
ALTER DATABASE [dvbbs] SET MULTI_USER BRU9LS
GO .`Old{<
7、日志清除 C+(Gg^ w
SET NOCOUNT ON Z>Kcz^a#
DECLARE @LogicalFileName sysname, .)^3t~
@MaxMinutes INT, _/%]:
@NewSize INT FQ|LA[~
USE tablename -- 要操作的数据库名 n?e@):
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 o eJC
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Z!RRe]"y
@NewSize = 1 -- 你想设定的日志文件的大小(M) `YmI'
-- Setup / initialize Q0q)n=i}]
DECLARE @OriginalSize int )'
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SELECT @OriginalSize = size H&yFSz}6a
FROM sysfiles ~b$z\|Y
WHERE name = @LogicalFileName wO_pcNYZ8
SELECT 'Original Size of ' + db_name() + ' LOG is ' + A.$VM#
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + RZ)vU'@kx
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1f@U:<:
FROM sysfiles uWR,6\_jY
WHERE name = @LogicalFileName HDSA]{:sl
CREATE TABLE DummyTrans z@%/r~?|
(DummyColumn char (8000) not null) J!A/r<
DECLARE @Counter INT, 34m' ]n
@StartTime DATETIME, Q9eYF-+
@TruncLog VARCHAR(255) m['v3m:
SELECT @StartTime = GETDATE(), 01-\:[{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q(&^9"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _]=TFz2O
EXEC (@TruncLog) ndKvJH 4
-- Wrap the log if necessary. @u"kX2>Eq
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired C?/r}ly<\
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) C;)Xwm>e
AND (@OriginalSize * 8 /1024) > @NewSize 8!&ds~?
BEGIN -- Outer loop. =Y]'5cn{
SELECT @Counter = 0 qtdxMX]iR
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) J]|6l/i
BEGIN -- update K.#,O+-Kg`
INSERT DummyTrans VALUES ('Fill Log') /UaNYv/
DELETE DummyTrans cFI7}#,5
SELECT @Counter = @Counter + 1 ^`TKvcgIc
END 3D$\y~HU
EXEC (@TruncLog) 0+n&BkS'
END 7SA-OFM
SELECT 'Final Size of ' + db_name() + ' LOG is ' + TRySl5jx@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :_fjml/
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' DX&lBV
FROM sysfiles zO).<xIq+
WHERE name = @LogicalFileName n $O.>
DROP TABLE DummyTrans +9 16ZPk
SET NOCOUNT OFF qUEd
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8、说明:更改某个表 iJdrY6qd
exec sp_changeobjectowner 'tablename','dbo' EG(`E9DZ
9、存储更改全部表 \sHy. {
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch VNr
@OldOwner as NVARCHAR(128), B~V<n&<
@NewOwner as NVARCHAR(128) 75\RG+kQ
AS %2Xus9;k#
DECLARE @Name as NVARCHAR(128) X]zCTY=l
DECLARE @Owner as NVARCHAR(128) ~C/Yv&58
DECLARE @OwnerName as NVARCHAR(128) e_I; y
DECLARE curObject CURSOR FOR c#\ah}]Vo
select 'Name' = name, oRT
'Owner' = user_name(uid) X ]pR,\B
from sysobjects nCffBc
where user_name(uid)=@OldOwner e8XM=$@
order by name VW{aUgajO
OPEN curObject kO..~@aY
FETCH NEXT FROM curObject INTO @Name, @Owner kwDh|K
WHILE(@@FETCH_STATUS=0) I8<Il^
BEGIN Giy3eva2
if @Owner=@OldOwner }sTH.%
begin (E"&UC[
set @OwnerName = @OldOwner + '.' + rtrim(@Name) uKR\Xo}
exec sp_changeobjectowner @OwnerName, @NewOwner Q*09E
end ;1*m}uNz
-- select @name,@NewOwner,@OldOwner <K DH
FETCH NEXT FROM curObject INTO @Name, @Owner Nl=m'4@`
END S.Wh4kMUe
close curObject HQ|o%9~
deallocate curObject ^Txu~r0@
GO xUiWiOihr6
10、SQL SERVER中直接循环写入数据 Qfkh0DX
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declare @i int (aDb^(]>
set @i=1 n=<NFkeX
while @i<30 |dl0B26x
begin "t(1tWO1o
insert into test (userid) values(@i)
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set @i=@i+1 + AcKB82
end _XH4;uGg
小记存储过程中经常用到的本周,本月,本年函数 eD*?q7
Dateadd(wk,datediff(wk,0,getdate()),-1) R/ALR
Dateadd(wk,datediff(wk,0,getdate()),6) z9k*1:
Dateadd(mm,datediff(mm,0,getdate()),0) g:3d<CS
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) msA' 5>
Dateadd(yy,datediff(yy,0,getdate()),0) Ax5mP8S
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) O3^98n2
上面的SQL代码只是一个时间段 ^ [X|As2
Dateadd(wk,datediff(wk,0,getdate()),-1) u"`5
Dateadd(wk,datediff(wk,0,getdate()),6) {\vI9cni|"
就是表示本周时间段. :DOr!PNA
下面的SQL的条件部分,就是查询时间段在本周范围内的: o9KyAP$2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 4c5^7";P
而在存储过程中 avu*>SB
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) UC8vR>e\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Whv]88w{