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。 -?{g{6
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一、基础 5
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1、说明:创建数据库 Iue=\qUK^
CREATE DATABASE database-name 2,Z@<
2、说明:删除数据库 K$:btWSm
drop database dbname >){}nlQf
3、说明:备份sql server M_cm,|FF
--- 创建 备份数据的 device 4@mJEi{
USE master U;u4ey
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Al *yx_j
--- 开始 备份 6L
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BACKUP DATABASE pubs TO testBack Uqj$itqUQ
4、说明:创建新表 =>Qd
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) i=rA;2>
根据已有的表创建新表: ;yjw(OAI*
A:create table tab_new like tab_old (使用旧表创建新表) | "M1+(k7
B:create table tab_new as select col1,col2... from tab_old definition only Ytqx0
5、说明:删除新表 Hl{ul'o
drop table tabname g_>E5z.
6、说明:增加一个列 n? =O@yq
Alter table tabname add column col type {3K]Q=
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。 OH]45bd
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7、说明:添加主键: Alter table tabname add primary key(col) Y<N#{)Q
说明:删除主键: Alter table tabname drop primary key(col) $ER$|9)KD
8、说明:创建索引:create [unique] index idxname on tabname(col....) _Vt9ckaA
删除索引:drop index idxname hM="9]i.
注:索引是不可更改的,想更改必须删除重新建。 MAX?,-x
9、说明:创建视图:create view viewname as select statement KZ65#UVX
删除视图:drop view viewname /1.Z=@ 7
10、说明:几个简单的基本的sql语句 q%]5/.J
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) .>_%12>
删除:delete from table1 where 范围 opzlh@R
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更新:update table1 set field1=value1 where 范围 _o+OkvhU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8)Vl2z
排序:select * from table1 order by field1,field2 [desc] W4(
总数:select count as totalcount from table1 HB.:/5\
求和:select sum(field1) as sumvalue from table1 -sDl[
平均:select avg(field1) as avgvalue from table1 A5%Now;.cf
最大:select max(field1) as maxvalue from table1 6-5{7E}/b
最小:select min(field1) as minvalue from table1 XI`s M~'
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11、说明:几个高级查询运算词 Klu0m~X@
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A: UNION 运算符 {S@,
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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。 h+YPyeAs
B: EXCEPT 运算符 !g|[A7<|
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。 '*&V7:
C: INTERSECT 运算符 wLE|J9t%Ea
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。 o{hZjn-
注:使用运算词的几个查询结果行必须是一致的。 3(*vZ
12、说明:使用外连接 mOyNl
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A、left outer join: ]a*26AbU+
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。 20Jlf?
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 L$, Kdpj
B:right outer join: cmd7-2
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 "s`#`'
C:full outer join: #0^a-47PA<
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 N?A}WW#
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二、提升 AnZy
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) `J7@G]X;2
法一:select * into b from a where 1<>1 }<'ki
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法二:select top 0 * into b from a tv]9n8v
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =*6H!bzX
insert into b(a, b, c) select d,e,f from b; HuN_$aP
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) 4>B=k
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (Bpn9}F-V.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. R-4#y%k<
4、说明:子查询(表名1:a 表名2:b) <p`
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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) \,!Qo*vj
5、说明:显示文章、提交人和最后回复时间 lx~C{tl2
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ys7Tq+
6、说明:外连接查询(表名1:a 表名2:b) y^
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c &*Kk>
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7、说明:在线视图查询(表名1:a ) Q
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select * from (SELECT a,b,c FROM a) T where t.a > 1; w`=XoYQl~*
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 #??[;xjs!
select * from table1 where time between time1 and time2 T7Ju7_q}
select a,b,c, from table1 where a not between 数值1 and 数值2 5pff}Ru`
9、说明:in 的使用方法 1@~ 1vsJ
select * from table1 where a [not] in ('值1','值2','值4','值6') eG.s|0`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 YWk+}y}^d
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Tg=P*HY6
11、说明:四表联查问题: yhnPS4DC
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 ..... x69RQ+Vw
12、说明:日程安排提前五分钟提醒 l @E
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 yi -0CHo
13、说明:一条sql 语句搞定数据库分页 -BwZ
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 ,~Lx7 5{
14、说明:前10条记录 {817Svp@
select top 10 * form table1 where 范围 A9GSeW<
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.) :j32 :/u
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) f]Rh<N$
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 >LVGNicQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) X&M04
17、说明:随机取出10条数据 LMp^]*)t
select top 10 * from tablename order by newid() Z:,`hW*A6
18、说明:随机选择记录 <?Z]h]C^o
select newid() 4`+R
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19、说明:删除重复记录 q1rD>n&d
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %."w]fy>P
20、说明:列出数据库里所有的表名 \@{TF((Y
select name from sysobjects where type='U' WZviC_
21、说明:列出表里的所有的 v++&%
select name from syscolumns where id=object_id('TableName') {~'Iu8TvZ
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。 ,OMdLXr
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 ?MSV3uODb
显示结果: Jgq#m~M6
type vender pcs wS|hc+1
电脑 A 1 hSj@<#b>F
电脑 A 1 >``
光盘 B 2 [[ll4|
光盘 A 2 J)H*tzg
手机 B 3 TCkMJs?
手机 C 3 Dh68=F0
23、说明:初始化表table1 n<A<Xj08T9
TRUNCATE TABLE table1 >52%^ ?
24、说明:选择从10到15的记录 p y%:,hi
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc A^\g]rmK
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三、技巧 !~xlze
1、1=1,1=2的使用,在SQL语句组合时用的较多 /.t1Ow
"where 1=1" 是表示选择全部 "where 1=2"全部不选, yQN^F+.
如: wEU=R>j.
if @strWhere !='' X#fjIrn
begin {_Fh3gjb/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ia[<;":U
end mPo.Z"uy7
else ;O<-4$
begin |[)pQGw
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?YF2Uc8z%2
end Z~;rp`P
我们可以直接写成 IJ7wUZp"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ir Y\Q)
2、收缩数据库 fY|[YPGO^
--重建索引 \
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DBCC REINDEX nJwP|P_
DBCC INDEXDEFRAG Qs<L$"L1
--收缩数据和日志 A,?6|g`q'
DBCC SHRINKDB {r#uD5NJ/
DBCC SHRINKFILE d@ ]N
3、压缩数据库 [<wpH0lNoy
dbcc shrinkdatabase(dbname) *rYPjk6g[
4、转移数据库给新用户以已存在用户权限 /^WOrMR
exec sp_change_users_login 'update_one','newname','oldname' A~<cp)E
go z0|-OCmL
5、检查备份集 ]VS:5kOj`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' {f;DhB-jj
6、修复数据库 {"|la;*I
ALTER DATABASE [dvbbs] SET SINGLE_USER _]L]_Bh
GO Zlrbd
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK DbYnd%k*4
GO 5+qdn|9%T
ALTER DATABASE [dvbbs] SET MULTI_USER TQQh:y
GO 0y2zjXM;3
7、日志清除 I*n]8c
SET NOCOUNT ON Qve5qJ
DECLARE @LogicalFileName sysname, hG272s 2
@MaxMinutes INT, \:2z!\iP`
@NewSize INT tY#Zl 54~{
USE tablename -- 要操作的数据库名 `w)yR>lqh
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 <s$Jj><
@MaxMinutes = 10, -- Limit on time allowed to wrap log. t~":'le`zr
@NewSize = 1 -- 你想设定的日志文件的大小(M) $Xqc'4YOZ
-- Setup / initialize ;/)$Cm &e
DECLARE @OriginalSize int _\{/#J;lN
SELECT @OriginalSize = size f6{.Uq%SGp
FROM sysfiles ;s+3#Py
WHERE name = @LogicalFileName =>@
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8TTj<T!N
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + e2L>"/
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' `$3ktQ $
FROM sysfiles 3r[s_Y*
WHERE name = @LogicalFileName O,#,` 2Qc
CREATE TABLE DummyTrans 8EBd`kiq
(DummyColumn char (8000) not null) [I7=]X
DECLARE @Counter INT, (B03f$8}*_
@StartTime DATETIME, E
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@TruncLog VARCHAR(255) 0-/@-qV\
SELECT @StartTime = GETDATE(), B[t>T>~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' #+$PD`j
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 46~nwi$,^
EXEC (@TruncLog) Tt,T6zs-<
-- Wrap the log if necessary. N:%Nq8I}:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired **.23<n^W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) s|X_:3\x
AND (@OriginalSize * 8 /1024) > @NewSize ant2];0p
BEGIN -- Outer loop. #c~-8=
SELECT @Counter = 0 l8e)|MSh
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) { _Y'%Ggh
BEGIN -- update \C{Zqo,
INSERT DummyTrans VALUES ('Fill Log') /)<kG(Z
DELETE DummyTrans .kJu17!
SELECT @Counter = @Counter + 1 >;%LW}
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END J|VDZ# c7
EXEC (@TruncLog) Y' 5X4Ks|
END n'%cO]nSx
SELECT 'Final Size of ' + db_name() + ' LOG is ' + AtxC(gm 1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4M+f#b1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' sejT] rJ
FROM sysfiles 4JXJ0T ar
WHERE name = @LogicalFileName z0F55<i
DROP TABLE DummyTrans B9H.8+~(
SET NOCOUNT OFF !_W']Crb]]
8、说明:更改某个表 -#R63f&
exec sp_changeobjectowner 'tablename','dbo' f*T}Ov4
9、存储更改全部表 PfGiJ]:V-u
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ezri9\Ju
@OldOwner as NVARCHAR(128), 5JhpBx/>o=
@NewOwner as NVARCHAR(128) '2rSX[$tf
AS jc@=
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DECLARE @Name as NVARCHAR(128) }G!'SZ$F 5
DECLARE @Owner as NVARCHAR(128) 'z@]hm#
DECLARE @OwnerName as NVARCHAR(128) C'jCIL
DECLARE curObject CURSOR FOR 2X(2O':Uc
select 'Name' = name, f 0~Z@\
'Owner' = user_name(uid) 7e D`
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from sysobjects w7 \vrS>&
where user_name(uid)=@OldOwner J?tnS6V
order by name 6="o&!
OPEN curObject \x5>H:\Y
FETCH NEXT FROM curObject INTO @Name, @Owner fG{3S:TQq
WHILE(@@FETCH_STATUS=0) fd62m]X
BEGIN "Nz"|-3Irv
if @Owner=@OldOwner Yq:/dpA_
begin e-.(O8
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1f?Fuw
exec sp_changeobjectowner @OwnerName, @NewOwner uzLm TmM+
end `m$,8f%j6_
-- select @name,@NewOwner,@OldOwner $U(D*0+o/
FETCH NEXT FROM curObject INTO @Name, @Owner mxe\+j#
END <TSps!(#
close curObject "chf\-!$
deallocate curObject J%fJF//U
GO a
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10、SQL SERVER中直接循环写入数据 R@`xS<`L/
declare @i int ETR7%0$r
set @i=1 ?zVcP=p@
while @i<30 dkSd
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begin )]Sf|@K]
insert into test (userid) values(@i) v[?gM.SF
set @i=@i+1 9<"F3F0|
end Urksj:N
小记存储过程中经常用到的本周,本月,本年函数 nFro#qx
Dateadd(wk,datediff(wk,0,getdate()),-1) ?q0a^c?A^
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) M3dUGM
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZvK3Su)f1
Dateadd(yy,datediff(yy,0,getdate()),0) vY[u;VU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %f(4jQ0I
上面的SQL代码只是一个时间段 dN){w _
Dateadd(wk,datediff(wk,0,getdate()),-1) CurU6x1
Dateadd(wk,datediff(wk,0,getdate()),6) WMFn#.aY5
就是表示本周时间段. ;#*.@Or@Ah
下面的SQL的条件部分,就是查询时间段在本周范围内的: h645;sb0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CI+li H
而在存储过程中 d[E= HN
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }R:oWR
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]n$ v ^