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。 0:>C v<N
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一、基础 AiV1
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1、说明:创建数据库 X,+N/nku
CREATE DATABASE database-name Otm7j>w
2、说明:删除数据库 "I[uD)$
drop database dbname {=E,.%8
3、说明:备份sql server !f8]gT zN
--- 创建 备份数据的 device 4({Wipd
USE master TJ(vq] |&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Hb9r.;r<EW
--- 开始 备份 'jU ;.vZex
BACKUP DATABASE pubs TO testBack v;R+{K87
4、说明:创建新表 Q .cL1uHc
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iA+zZVwO
根据已有的表创建新表: \MmKz^tO
A:create table tab_new like tab_old (使用旧表创建新表) p!cNn7{;
B:create table tab_new as select col1,col2... from tab_old definition only TbhsOf!
5、说明:删除新表 to'O;f">n
drop table tabname D??
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6、说明:增加一个列 4:XVu
Alter table tabname add column col type
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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。 `[.4SIah
7、说明:添加主键: Alter table tabname add primary key(col) o}lA\ A
说明:删除主键: Alter table tabname drop primary key(col) Kdb:Q0B
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^g N?Io
删除索引:drop index idxname s!K9-qZl<
注:索引是不可更改的,想更改必须删除重新建。 K9euNa
9、说明:创建视图:create view viewname as select statement zzyD'n7D
删除视图:drop view viewname 3VmF1w
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10、说明:几个简单的基本的sql语句 1?ST*b
选择:select * from table1 where 范围 DUu~s,A
插入:insert into table1(field1,field2) values(value1,value2) )'t&LWS~
删除:delete from table1 where 范围 NiH.Pv)Oa'
更新:update table1 set field1=value1 where 范围 #N|A@B5x
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )m$i``*<
排序:select * from table1 order by field1,field2 [desc] C]%}L%,
总数:select count as totalcount from table1 o_%gFV[q
求和:select sum(field1) as sumvalue from table1 'tzN.p1O
平均:select avg(field1) as avgvalue from table1 uF\f>E)/N%
最大:select max(field1) as maxvalue from table1 l#%G~c8x
最小:select min(field1) as minvalue from table1 *Y9' tHI
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11、说明:几个高级查询运算词 83YQ c
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A: UNION 运算符 ?O#,|\v?]
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 V']1j
B: EXCEPT 运算符 u-#J!Z<T8
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 -Mufo.Jz1o
C: INTERSECT 运算符 I)cA:Ip
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 PsoW:t
注:使用运算词的几个查询结果行必须是一致的。 Z <vTr6?
12、说明:使用外连接 Z "g6z#L&
A、left outer join: 6I$:mHEhd
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。 1
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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 {'eF;!!Dy
B:right outer join: 7W\aX*]
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。 m^ [VM&%
C:full outer join: S?LUSb
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。 iQ_^MzA
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二、提升 `?xE-S
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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) 5Gsjt+
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法一:select * into b from a where 1<>1 8n)3'ok
法二:select top 0 * into b from a gpzZs<ST
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #`{L_n$c
insert into b(a, b, c) select d,e,f from b; 9q
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3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) -
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 :~+m9r
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. w?zY9Fs=s
4、说明:子查询(表名1:a 表名2:b) K
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) B< BS>(Nr>
5、说明:显示文章、提交人和最后回复时间 14;lB.$p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7[u$!.4{*
6、说明:外连接查询(表名1:a 表名2:b) Stxrgmu
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c WL/9r
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7、说明:在线视图查询(表名1:a ) "f<+~
select * from (SELECT a,b,c FROM a) T where t.a > 1; j*}2AI
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 "jG-)k`a
select * from table1 where time between time1 and time2 ,}_uk]AQ
select a,b,c, from table1 where a not between 数值1 and 数值2 $>y
9、说明:in 的使用方法 '2.11cM3
select * from table1 where a [not] in ('值1','值2','值4','值6') dX:#KdK
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :*{\oqFn~$
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _Zs]za.#)|
11、说明:四表联查问题: gdfG3d$4
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *Me{G y
12、说明:日程安排提前五分钟提醒 bv8GJ #
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 T hLR<\
13、说明:一条sql 语句搞定数据库分页 !`F^LXGA
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 @s/0 .7
14、说明:前10条记录 hz_F^gF
select top 10 * form table1 where 范围 f.y~ Sew
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) `T;Y%"X!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) n32.W?9
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 *<nfA}
(select a from tableA ) except (select a from tableB) except (select a from tableC) v\?J$Hdd
17、说明:随机取出10条数据 Ffp<|2T2_
select top 10 * from tablename order by newid() N`%f+eT(
18、说明:随机选择记录 ]w[T_4l
select newid() [e+$jsPl
19、说明:删除重复记录 fnm:Wa|,%|
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) IB+)2 `
20、说明:列出数据库里所有的表名 vs~lyM/
select name from sysobjects where type='U' r 2L=gI
21、说明:列出表里的所有的 D1VM_O
select name from syscolumns where id=object_id('TableName') Co#_Cyxg=9
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 #yVMC;J?W
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type /i)1BaF
显示结果: k|c=O6GO
type vender pcs qEbzF#a-:
电脑 A 1 k_<8SG+`
电脑 A 1 _z3YB
光盘 B 2 `Gp!Y
光盘 A 2 edy6WzxBcm
手机 B 3 oPA
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手机 C 3 fCxF3m(O
23、说明:初始化表table1 !1\jD
TRUNCATE TABLE table1 T{%'"mm;
24、说明:选择从10到15的记录 ]\t+zF>&Y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {Qla4U
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三、技巧 `e!hT@Xxa
1、1=1,1=2的使用,在SQL语句组合时用的较多 2dF:;k k
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /o_h'l|PS
如: b|HH9\
if @strWhere !='' Qe )#'$T
begin axW4cS ?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere hj.Du+1
end Xqac$%[3
else S(f V ,;Z
begin 8?7gyp!k_f
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ag!#epi{0
end GCgpe(cQ
我们可以直接写成 a~-^$Fzgy
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S3k>34_%9
2、收缩数据库 hsUP5_
--重建索引 E0i_sB~T
DBCC REINDEX CF`fn6
DBCC INDEXDEFRAG tyLR_@i%%
--收缩数据和日志 MXxE)"G*a
DBCC SHRINKDB P00pSRQHD
DBCC SHRINKFILE `(9B(&t^,
3、压缩数据库 /B?hM&@z
dbcc shrinkdatabase(dbname) 6v9{$:
4、转移数据库给新用户以已存在用户权限 ]3E':JM@
exec sp_change_users_login 'update_one','newname','oldname' j;k(AM<
go 92k}ON
5、检查备份集 -~HlME*~f
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e]+ [lq\p@
6、修复数据库 c[Mz#BWG
ALTER DATABASE [dvbbs] SET SINGLE_USER (Rc0 l;
GO U "qO&;m
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -0)So
GO ~"*;lT5KX
ALTER DATABASE [dvbbs] SET MULTI_USER B43o_H|s
GO pw7_j;}l
7、日志清除 UI4Xv
SET NOCOUNT ON Vo%UiVHy
DECLARE @LogicalFileName sysname, diLjUC`69
@MaxMinutes INT, Wsr #YNhx|
@NewSize INT S"=oU}'|
USE tablename -- 要操作的数据库名 3o'SY@'W
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 rGZ@pO2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. h ,@x5q>g
@NewSize = 1 -- 你想设定的日志文件的大小(M) Wb4%=2Qn
-- Setup / initialize \4SFD3$&
DECLARE @OriginalSize int 3\,TI`^C
SELECT @OriginalSize = size Xm`K@hJ@
FROM sysfiles JHf}LZu
WHERE name = @LogicalFileName C%P"Ds=w0N
SELECT 'Original Size of ' + db_name() + ' LOG is ' + hfvs'.
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + _e_]$G/TM
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?nFT51t/4
FROM sysfiles XU0"f!23x
WHERE name = @LogicalFileName P-~Avb
CREATE TABLE DummyTrans *TuoC5
(DummyColumn char (8000) not null) #oYX0wvl
DECLARE @Counter INT, 9tS&$-
@StartTime DATETIME, >NwrJSx
@TruncLog VARCHAR(255) u%O^hcfb
SELECT @StartTime = GETDATE(), fxLhVJ"b
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' J<_&f_K0]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LwUvM
EXEC (@TruncLog) aAko-,URC
-- Wrap the log if necessary. !qH=l-7A
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired &%Hj.
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )`rC"N)
AND (@OriginalSize * 8 /1024) > @NewSize
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BEGIN -- Outer loop. $gZ|=(y&r
SELECT @Counter = 0 1F5F2OT$8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) eT+MN`
BEGIN -- update 5b B[o6+
INSERT DummyTrans VALUES ('Fill Log') -o#0Yt}3
DELETE DummyTrans s=huOjKL]
SELECT @Counter = @Counter + 1 k#%19B
END /$rS0@p
EXEC (@TruncLog) nWZrB s
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END "`:#sF9S
SELECT 'Final Size of ' + db_name() + ' LOG is ' + qc\o>$-:`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + }7$\F!R
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !*%3um
FROM sysfiles !9o8v0ZI
WHERE name = @LogicalFileName -T{~m6
DROP TABLE DummyTrans gr=ke #
SET NOCOUNT OFF Qb# S)[6s+
8、说明:更改某个表 VH*j3
exec sp_changeobjectowner 'tablename','dbo' y&__2t^u
9、存储更改全部表 "_)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 3iWLo Qm
@OldOwner as NVARCHAR(128), c_^H;~^rL
@NewOwner as NVARCHAR(128) nbpN+a%
AS Zt` ,DM
DECLARE @Name as NVARCHAR(128) xs &vgel>
DECLARE @Owner as NVARCHAR(128) wq]nz!
DECLARE @OwnerName as NVARCHAR(128) y i@61XI
DECLARE curObject CURSOR FOR dl{3fldb
select 'Name' = name, v2@M,xbxF:
'Owner' = user_name(uid) V43JY_:
from sysobjects udc9$uO
where user_name(uid)=@OldOwner `%ymg8^
order by name 00pHnNoxW
OPEN curObject 1shvHmrV
FETCH NEXT FROM curObject INTO @Name, @Owner Eun%uah6c
WHILE(@@FETCH_STATUS=0) tOko %vY8
BEGIN <1jiU%!w
if @Owner=@OldOwner ~`N|sI,
begin G8oQSo;D
set @OwnerName = @OldOwner + '.' + rtrim(@Name) NM]6 o
exec sp_changeobjectowner @OwnerName, @NewOwner I3s}t$`y(
end 8'cD K[L
-- select @name,@NewOwner,@OldOwner Ra*9d]N@
FETCH NEXT FROM curObject INTO @Name, @Owner Vr0RdO
END x@k9]6/zs
close curObject b`:Eo+p
deallocate curObject L7xTAFe
GO !E7/:t4
10、SQL SERVER中直接循环写入数据 Ta[}k/zW
declare @i int @/7Rp8Fr
set @i=1 g*]<]%Py"
while @i<30 3S5QqAm
begin /r?X33D!
insert into test (userid) values(@i) =C:0='a
set @i=@i+1 R\+$^G}#6
end q{_buTARq
小记存储过程中经常用到的本周,本月,本年函数 /cjf 1Dc
Dateadd(wk,datediff(wk,0,getdate()),-1) H+0 *
Dateadd(wk,datediff(wk,0,getdate()),6) 5g&'n
Dateadd(mm,datediff(mm,0,getdate()),0) a,tP.Xsl
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) j/Kw-h ,5"
Dateadd(yy,datediff(yy,0,getdate()),0) iCEX|Tj;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) p' gv5\u[w
上面的SQL代码只是一个时间段 <n`|zQ
Dateadd(wk,datediff(wk,0,getdate()),-1) _88~uYG
Dateadd(wk,datediff(wk,0,getdate()),6) `H|g~7KD&
就是表示本周时间段. I%s/h4x^B[
下面的SQL的条件部分,就是查询时间段在本周范围内的: QTyl=z7
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $ `ho+
而在存储过程中 #e0+;kBh
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) jf2E{48P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 3~S~)quwP