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。 3^fZUldf
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一、基础 t4JGd)r
1、说明:创建数据库 '@:;oe@]
CREATE DATABASE database-name ioviJ7N%
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2、说明:删除数据库 A2vOI8
drop database dbname d>aZpJ[.
3、说明:备份sql server v\HGL56T
--- 创建 备份数据的 device a1}W2;W0]g
USE master Z>D7C?v:(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' bh_ALu^CSX
--- 开始 备份 PuOo^pFhH
BACKUP DATABASE pubs TO testBack #h&?wE>
4、说明:创建新表 S9L3/P]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) LEhi/>T
根据已有的表创建新表: (Q'XjN\#
A:create table tab_new like tab_old (使用旧表创建新表) ;wN.RPE_^
B:create table tab_new as select col1,col2... from tab_old definition only R]r~TJ o
5、说明:删除新表 }U(^ QB
drop table tabname ]>AW
6、说明:增加一个列 r`&ofk1K
Alter table tabname add column col type " 7aFVf
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。 9u)h$VC
7、说明:添加主键: Alter table tabname add primary key(col) Og&2,`Jb
说明:删除主键: Alter table tabname drop primary key(col) OIoAqt
8、说明:创建索引:create [unique] index idxname on tabname(col....) /qp`xJ
删除索引:drop index idxname $rlIJwqn
注:索引是不可更改的,想更改必须删除重新建。 X;0EgIqh3
9、说明:创建视图:create view viewname as select statement Tru`1/ 7I
删除视图:drop view viewname ML'R[~|
10、说明:几个简单的基本的sql语句 6-JnT_
选择:select * from table1 where 范围 iFHVr'Og'
插入:insert into table1(field1,field2) values(value1,value2) $:xUXEi{
删除:delete from table1 where 范围 e@q[Dv'mu
更新:update table1 set field1=value1 where 范围 +}1]8:>cq
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ooD/QZUE
排序:select * from table1 order by field1,field2 [desc] 77
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总数:select count as totalcount from table1 k\%{1oRA
求和:select sum(field1) as sumvalue from table1 dE^'URBiA
平均:select avg(field1) as avgvalue from table1 epwXv|aSZ
最大:select max(field1) as maxvalue from table1 b"zq3$6*
最小:select min(field1) as minvalue from table1 9S<W~# zz
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11、说明:几个高级查询运算词 w"sRK
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A: UNION 运算符 #F9$"L1Hg
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。 Uvuvr_IP
B: EXCEPT 运算符 S\f^y8*<
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。 7<KRB\)b&
C: INTERSECT 运算符 -kJF@w6u
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。 [mwfgh&4%
注:使用运算词的几个查询结果行必须是一致的。 ~pw_*AN
12、说明:使用外连接 ,fNiZ
A、left outer join: \
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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。 G)putk@
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 r&H>JCRZ<=
B:right outer join: ^]v}AEcmW
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。 %]
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C:full outer join: l >O]Cpt
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。 "w A8J%:
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二、提升 %TR->F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 8"4`W~ 3
法一:select * into b from a where 1<>1 H(g&+Wcu=
法二:select top 0 * into b from a T"0a&.TLj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 9!R !H&
insert into b(a, b, c) select d,e,f from b; ^ ]B&7\w"t
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) "W1 q}4_
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =DqGm]tA
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) 1'g?B`
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) \/,SH?>4x
5、说明:显示文章、提交人和最后回复时间 %%f=aPw
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %bv<OMD
6、说明:外连接查询(表名1:a 表名2:b) OrH&dY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <n#JOjHV
7、说明:在线视图查询(表名1:a ) )wGC=,
select * from (SELECT a,b,c FROM a) T where t.a > 1; SC!IQ80H#D
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 ~svu0[Vx
select * from table1 where time between time1 and time2 aN7u
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select a,b,c, from table1 where a not between 数值1 and 数值2 [Y:HVr,
9、说明:in 的使用方法 --]\z* x
select * from table1 where a [not] in ('值1','值2','值4','值6') ~#-`Qh
10、说明:两张关联表,删除主表中已经在副表中没有的信息 "zv+|_ZAfd
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $]hf2Yr(
11、说明:四表联查问题: ))MP]j9
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... U}
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12、说明:日程安排提前五分钟提醒 bLUn0)c
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 hMD yE.X-
13、说明:一条sql 语句搞定数据库分页 D_8hn3FH
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Jv7M[SJ#x
14、说明:前10条记录 |Rl|Th
select top 10 * form table1 where 范围 u!X2ju<
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) mq
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) A#p@`|H#B
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 1%+0OmV&
(select a from tableA ) except (select a from tableB) except (select a from tableC) KYeA=
17、说明:随机取出10条数据 A7sej
select top 10 * from tablename order by newid() EdU3k'z$
18、说明:随机选择记录 6Qo6T][
select newid() iffU}ce
19、说明:删除重复记录 E O}(MXS
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ^oP]@r"qy
20、说明:列出数据库里所有的表名 @emZwN"m
select name from sysobjects where type='U' uD5i5,q1Hs
21、说明:列出表里的所有的 ,<[os
select name from syscolumns where id=object_id('TableName') #VrT)po+
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。 %ZxKN ;
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 pjoI};
显示结果: )zt5`"/o
type vender pcs aNwDMd^+
电脑 A 1 $iB(N ZV
电脑 A 1 }M1<a4~
光盘 B 2 7>4t{aRf_8
光盘 A 2 ](W#Tj5-
手机 B 3 Xau.4&\d
手机 C 3 *]EcjK%
23、说明:初始化表table1 TLkkB09fvk
TRUNCATE TABLE table1 f8n'9HOw>
24、说明:选择从10到15的记录 zb3ir|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc g-]td8}#
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三、技巧 |g9^]bT
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]:f1r8<3p
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Z@*Z@]FC
如: "q%)we
if @strWhere !='' SnXLjJe
begin 6suc0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere jG/kT5S
end InDR\=o
else N7e^XUG
begin ?K]k(ZV_+Y
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' xNONf4I:6J
end 4C2 Dwj
我们可以直接写成 WH/a#F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ylf 6-FbF
2、收缩数据库 hVID~L$
--重建索引 5-g0 2g
DBCC REINDEX `ybZE+S.
DBCC INDEXDEFRAG iUO5hdOM
--收缩数据和日志 <>R7G)w
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DBCC SHRINKDB kxO$Uk&TX
DBCC SHRINKFILE :Rq D0>1
3、压缩数据库 *R:nB)(6<
dbcc shrinkdatabase(dbname) 5|/vc*m_0'
4、转移数据库给新用户以已存在用户权限 m1cyCD
exec sp_change_users_login 'update_one','newname','oldname' nQgn^z#
go D +oo5
5、检查备份集 EuAa
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' g5?Fo%W
6、修复数据库 u|Ai<2b$
ALTER DATABASE [dvbbs] SET SINGLE_USER }%}eyLm(
GO MRa>@Jn??A
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x
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GO
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ALTER DATABASE [dvbbs] SET MULTI_USER b!N`@m=
GO 6yR7RF}
7、日志清除 JAn3
SET NOCOUNT ON 6?`py}:
DECLARE @LogicalFileName sysname, $51#xe
@MaxMinutes INT, ^=@%@mR/[C
@NewSize INT U9If%0P
USE tablename -- 要操作的数据库名 @GEvI2Vf.0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zL{KK9Or
@MaxMinutes = 10, -- Limit on time allowed to wrap log. kn<[v;+
@NewSize = 1 -- 你想设定的日志文件的大小(M) ~jPe9
-- Setup / initialize =*'`\}];"
DECLARE @OriginalSize int M\GS&K$lq
SELECT @OriginalSize = size isN"7y|r:X
FROM sysfiles FYi<+]HZ
WHERE name = @LogicalFileName q80?C.,`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;CC[>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + .FC1:y<aO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' yf$7<gwX
FROM sysfiles #(A>yW702
WHERE name = @LogicalFileName qv<VKJTi6]
CREATE TABLE DummyTrans ik]UzB
(DummyColumn char (8000) not null) 5n"'M&Ce
DECLARE @Counter INT, oo qNPLa
@StartTime DATETIME, LPXwfEHOm
@TruncLog VARCHAR(255) f&,.h"bS
SELECT @StartTime = GETDATE(), [m4<j
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ':fVb3A[*d
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
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EXEC (@TruncLog) H<q:+
-- Wrap the log if necessary. ,JjTzO
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired J0x)m2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Lh0<A%
AND (@OriginalSize * 8 /1024) > @NewSize 5=$D~>-#
BEGIN -- Outer loop. /f2*J
SELECT @Counter = 0 t4Z.b 5g
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) cBAA32wf
BEGIN -- update m3,v&Z
INSERT DummyTrans VALUES ('Fill Log') ^o{O5&i]
DELETE DummyTrans 4~
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SELECT @Counter = @Counter + 1 V^Nc0r
END "B\qp "N
EXEC (@TruncLog) l^SKd
END `yf#(YP
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _LS=O@s^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4}0s^>R
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' a]Lr<i8#%
FROM sysfiles YlYTH_L>E
WHERE name = @LogicalFileName 2#rF/!`^
DROP TABLE DummyTrans TN0dfba[
SET NOCOUNT OFF avT>0b:
8、说明:更改某个表 U_!6pqFc
exec sp_changeobjectowner 'tablename','dbo' {:? -)Xq
9、存储更改全部表 =A,i9Z&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _E1:3N|
@OldOwner as NVARCHAR(128), .|rpj&>g
@NewOwner as NVARCHAR(128) d6Z;\f7[
AS ;Z8K3p
DECLARE @Name as NVARCHAR(128) o|UZdGu
DECLARE @Owner as NVARCHAR(128) Bkcs4 x
DECLARE @OwnerName as NVARCHAR(128) 8
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DECLARE curObject CURSOR FOR 3cs'Oz<w
select 'Name' = name, *l5/q\D
'Owner' = user_name(uid) rSa3u*xB
from sysobjects \ET7
where user_name(uid)=@OldOwner OW6i2 >Or
order by name R[9[lQ'vR
OPEN curObject 5` Q#2
FETCH NEXT FROM curObject INTO @Name, @Owner }96^OQPE
WHILE(@@FETCH_STATUS=0) Q2+e`
BEGIN ,H|V\\
if @Owner=@OldOwner Iz ,C!c
begin \oaO7w,:"
set @OwnerName = @OldOwner + '.' + rtrim(@Name) yDHH05Yl
exec sp_changeobjectowner @OwnerName, @NewOwner p(
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end yYW>)
-- select @name,@NewOwner,@OldOwner w
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FETCH NEXT FROM curObject INTO @Name, @Owner z S^:Ng5
END K)&AR*Tc
close curObject |{Oe&j3|
deallocate curObject VkUMMq{
GO +.zriiF]i
10、SQL SERVER中直接循环写入数据 D VC};
declare @i int uu'~[SZlL
set @i=1 n}YRE`>D
while @i<30 r% qgLP{v
begin 7q(RQQp
insert into test (userid) values(@i) >y2gfD
set @i=@i+1 O>}aK.H
end 3Hr ZN+D
小记存储过程中经常用到的本周,本月,本年函数 tNq~M
Dateadd(wk,datediff(wk,0,getdate()),-1) ]r|X[9
Dateadd(wk,datediff(wk,0,getdate()),6) SkS
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Dateadd(mm,datediff(mm,0,getdate()),0) 0dXWy`Mn
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) XC~|{d
Dateadd(yy,datediff(yy,0,getdate()),0) g#:?Ay-m
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ut0oh
上面的SQL代码只是一个时间段 pWeKN`
Dateadd(wk,datediff(wk,0,getdate()),-1) l].dOso$`
Dateadd(wk,datediff(wk,0,getdate()),6) O,hT<
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就是表示本周时间段. VBy=X\w]
下面的SQL的条件部分,就是查询时间段在本周范围内的: V:yia^1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) rry 33
而在存储过程中 `2}Mz9mk
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) C?X^h{Tp
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) lNqYpyvy*