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。 3F[z]B
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一、基础 yiSv#wD9
1、说明:创建数据库 :u`
CREATE DATABASE database-name \$V~kgQ0
2、说明:删除数据库 z(aei(U=
drop database dbname 'F?T4
3、说明:备份sql server t@>Uc`%
--- 创建 备份数据的 device |OUr=b
USE master W'-B)li
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @.a[2,o_
--- 开始 备份 <E|i3\[p
BACKUP DATABASE pubs TO testBack :o&qJ%
4、说明:创建新表 GG5wiN*2S
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {XC# -3O
根据已有的表创建新表: SQ]&nDd
A:create table tab_new like tab_old (使用旧表创建新表) vR3'B3y
B:create table tab_new as select col1,col2... from tab_old definition only |(*ReQ?=
5、说明:删除新表 cMsm[D{b
drop table tabname - ~T LI&[
6、说明:增加一个列 V"#ie
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Alter table tabname add column col type ),mKEpf
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。 g599Lc&
7、说明:添加主键: Alter table tabname add primary key(col) vkOCyi?c
说明:删除主键: Alter table tabname drop primary key(col) #Fl"#g$
8、说明:创建索引:create [unique] index idxname on tabname(col....) H@qA X
删除索引:drop index idxname b/Z=FS2T
注:索引是不可更改的,想更改必须删除重新建。 =m:xf&r#
9、说明:创建视图:create view viewname as select statement B5~S&HQ?B6
删除视图:drop view viewname 0ym>Hbax)
10、说明:几个简单的基本的sql语句 B4r4PSB>!
选择:select * from table1 where 范围 R^<li;Km
插入:insert into table1(field1,field2) values(value1,value2) CbVU z<
删除:delete from table1 where 范围 MVs@~=
更新:update table1 set field1=value1 where 范围 xJa
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 0g,;Yzm
排序:select * from table1 order by field1,field2 [desc] cclx$)X1X
总数:select count as totalcount from table1 'mXf8
求和:select sum(field1) as sumvalue from table1 A/|To!R
平均:select avg(field1) as avgvalue from table1 c]v$C&FX
最大:select max(field1) as maxvalue from table1 5(^&0c>P
最小:select min(field1) as minvalue from table1 |yx]TD{~P
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11、说明:几个高级查询运算词 |`1lCyV\tE
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A: UNION 运算符 a"EX<6"
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。 PB_+:S^8
B: EXCEPT 运算符 B<u6Z!Pp2
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。 *8M0h9S$
C: INTERSECT 运算符 o|*ao2a
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。 l<>syHCH;L
注:使用运算词的几个查询结果行必须是一致的。 [`BMi-WQ
12、说明:使用外连接 g'ha7~w(p
A、left outer join: s3>,%8O6
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。 @#hd8_)A.
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 7IB<0
B:right outer join: WUm83"
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。 !1$QNxgi
C:full outer join: /bv1R5
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 vxhs1vh
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二、提升 brx
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) zc01\M
法一:select * into b from a where 1<>1 Uoe;4ni
法二:select top 0 * into b from a hCV e05
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) % 4|*
insert into b(a, b, c) select d,e,f from b; gHpA@jdC*
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) v;AsV`g
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }:<`L\8q\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4$#nciAe
4、说明:子查询(表名1:a 表名2:b) m-Q!V+XQp
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) i t.Lh'N;T
5、说明:显示文章、提交人和最后回复时间 UmUw>+A
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b epuN~T
6、说明:外连接查询(表名1:a 表名2:b) @E;'Ffo
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"sK@
7、说明:在线视图查询(表名1:a ) s!(O7Ub
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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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 I
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select * from table1 where time between time1 and time2 5Iine n3>
select a,b,c, from table1 where a not between 数值1 and 数值2 N4]QmRX/j
9、说明:in 的使用方法 Fk=Sx<TX
select * from table1 where a [not] in ('值1','值2','值4','值6') qM=
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 VPW@y
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7DZxrVw
11、说明:四表联查问题: GOrDDp
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 ..... tj$&89
12、说明:日程安排提前五分钟提醒 tIn
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 yw2Mr+9I
13、说明:一条sql 语句搞定数据库分页 $c"byQ[3S
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 9'nM$a
14、说明:前10条记录 wX5Yo{
select top 10 * form table1 where 范围 2[!#Xf
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.) hEUS&`K
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J<hqF4z
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 :/UO3 c(
(select a from tableA ) except (select a from tableB) except (select a from tableC) ko<u0SjF)u
17、说明:随机取出10条数据 9Rl-Jz8g
select top 10 * from tablename order by newid() [rk*4b ^s
18、说明:随机选择记录 8_byS<b8
select newid()
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19、说明:删除重复记录 .TZ0FxW
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) qaJ$0,]H+
20、说明:列出数据库里所有的表名 _=0%3Sh
select name from sysobjects where type='U' )45~YDS;t
21、说明:列出表里的所有的 >f+qImH
select name from syscolumns where id=object_id('TableName') NZT2ni4
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 p[oR4 HWr
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type <L'!EcHm%]
显示结果: 4SRjF$Bsz
type vender pcs 5&A{IN
电脑 A 1 _G3L+St
电脑 A 1 h,-2+}
光盘 B 2 8xf]zM"Q
光盘 A 2 vge4&H3a&
手机 B 3 2L!s'^m-
手机 C 3 ?R-4uG[(
23、说明:初始化表table1 bd|ZhRsL
TRUNCATE TABLE table1 N;Hoi8W
24、说明:选择从10到15的记录 g
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (sM$=M<$
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三、技巧 hc7"0mVd{
1、1=1,1=2的使用,在SQL语句组合时用的较多 X%(1C,C(
"where 1=1" 是表示选择全部 "where 1=2"全部不选, '`s\_Q)hG_
如: qmmQHS
if @strWhere !='' ^.3(o{g
begin eBT+|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CgT5sk}
end m[aBHA^g
else iA.:{^_)09
begin YQ? "~[mL
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ycD.X"
end j(aok5:e
我们可以直接写成 e^!>W %.7Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6&oaxAp<s
2、收缩数据库 <Wrn/%tL
--重建索引 I{nrOb1G(
DBCC REINDEX >wSrllmj@
DBCC INDEXDEFRAG %Z~0vwY
--收缩数据和日志 &VPfI
DBCC SHRINKDB (#e,tu
DBCC SHRINKFILE N[=c|frho
3、压缩数据库 K&"ZZFd_
dbcc shrinkdatabase(dbname) itYTV?bd
4、转移数据库给新用户以已存在用户权限 }BYs.$7
exec sp_change_users_login 'update_one','newname','oldname' . E8Gj'yO
go DXF>#2E^+
5、检查备份集 My6a.Kl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' .gQYN2#zb
6、修复数据库 aU\R!Y$/"
ALTER DATABASE [dvbbs] SET SINGLE_USER f]sc[_n]
GO q"LE6?hs
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK :,Zs{\oI3
GO R6m6bsZ`
ALTER DATABASE [dvbbs] SET MULTI_USER "!S7D>2y#
GO %+pF4f8]
7、日志清除 )L+>^cJI<
SET NOCOUNT ON J;DTh ]z?:
DECLARE @LogicalFileName sysname, bVxbQ$
@MaxMinutes INT, !kW~s_gUb*
@NewSize INT F[q)ME+`)
USE tablename -- 要操作的数据库名 X_HU?Q_N
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 qV{iUtYt
@MaxMinutes = 10, -- Limit on time allowed to wrap log. sq rY<@%
@NewSize = 1 -- 你想设定的日志文件的大小(M) dDrzO*a\
-- Setup / initialize SD_P=?
DECLARE @OriginalSize int |S6L[Uo
SELECT @OriginalSize = size ~'#yH#o
FROM sysfiles XpH d"(*
WHERE name = @LogicalFileName =D3K})&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + t) uS7y
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2rGg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' JZup} {a
FROM sysfiles Je*hyi7
WHERE name = @LogicalFileName <SKzCp\
CREATE TABLE DummyTrans 0/5{v6_rG
(DummyColumn char (8000) not null) Mp`!zwR
DECLARE @Counter INT, =G\N1E
@StartTime DATETIME, +/>XOY|Ie
@TruncLog VARCHAR(255) _aP2gH
SELECT @StartTime = GETDATE(), nPR*mbW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' jdf3XTw
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3D-VePM=`
EXEC (@TruncLog) &gdhq~4#
-- Wrap the log if necessary. ,p' ;Xg6ez
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ubs>(\`q"
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) M@]@1Q.p
AND (@OriginalSize * 8 /1024) > @NewSize #z#`EBXV$6
BEGIN -- Outer loop. v"YaMbu
SELECT @Counter = 0 .+A2\F.^
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) o?|
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BEGIN -- update -|2k$W
INSERT DummyTrans VALUES ('Fill Log') s 9n_s=w
DELETE DummyTrans F\2<q$Zn+
SELECT @Counter = @Counter + 1 jZgCDA8Mr!
END h f{RI 4Jc
EXEC (@TruncLog) F-=Xbyr3@
END o`M.v[O
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Yln[ZmK9g
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !NO)|N>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' jaL#
FROM sysfiles /k.?x] Ab
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans '/F%
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SET NOCOUNT OFF zP8rW5/
8、说明:更改某个表 quL+UFuM
exec sp_changeobjectowner 'tablename','dbo' 7-Mm+4O9
9、存储更改全部表 }B`T%(11=
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch h4E[\<?
@OldOwner as NVARCHAR(128), a}g<<{
@NewOwner as NVARCHAR(128) 24I\smO
AS Utj4f-M
DECLARE @Name as NVARCHAR(128) O`f[9^fN
DECLARE @Owner as NVARCHAR(128) 5 \iX%w@
DECLARE @OwnerName as NVARCHAR(128) P TH'-G
DECLARE curObject CURSOR FOR -\&b&; _
select 'Name' = name, lho0Xy
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'Owner' = user_name(uid) FT6~\9m(
from sysobjects 2*@@Bw.XA
where user_name(uid)=@OldOwner 5H2Ugk3
order by name ]sDlZJX<M
OPEN curObject }u.I%{4
FETCH NEXT FROM curObject INTO @Name, @Owner :yFmCLZaQ
WHILE(@@FETCH_STATUS=0) l.uW>AoLh
BEGIN m't8\fo^w
if @Owner=@OldOwner rm%MQmF
begin s x2\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +[":W?j
exec sp_changeobjectowner @OwnerName, @NewOwner ~COd(,ul
end >Yx,%a@~R
-- select @name,@NewOwner,@OldOwner &hnKBr(Lw
FETCH NEXT FROM curObject INTO @Name, @Owner L=&dJpyfT
END 5}4>vEn
close curObject 85rjM#~
deallocate curObject oAF#bj_f
GO 3vj1FbY
10、SQL SERVER中直接循环写入数据 _F`RwBOjs
declare @i int X\1.,]O >
set @i=1 5Ve
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while @i<30 \# _w=gs<i
begin ebiOR1)sN
insert into test (userid) values(@i) {ewo-dva
set @i=@i+1 \t
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end jJ3dZ<#
小记存储过程中经常用到的本周,本月,本年函数 '8c-V aa
Dateadd(wk,datediff(wk,0,getdate()),-1) X< 4f7;]O
Dateadd(wk,datediff(wk,0,getdate()),6) tY- `$U@
Dateadd(mm,datediff(mm,0,getdate()),0) W3A9uk6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &Fh#o t H_
Dateadd(yy,datediff(yy,0,getdate()),0) yDw#V`Y^M
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) lNx:_g:SrZ
上面的SQL代码只是一个时间段 *n_7~ZX
Dateadd(wk,datediff(wk,0,getdate()),-1) J0UF(
Dateadd(wk,datediff(wk,0,getdate()),6) Vi>`g{\
就是表示本周时间段. <KrfM
下面的SQL的条件部分,就是查询时间段在本周范围内的: uF\ ;m.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 1q/Q@O
而在存储过程中 )#v0.pE
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) AEo
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)
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