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。 }kItVx
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一、基础 O^6anUV0
1、说明:创建数据库 D@.qdRc3
CREATE DATABASE database-name 5}w
2、说明:删除数据库 -I6t ^$HA
drop database dbname Og@{6>
3、说明:备份sql server |&
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--- 创建 备份数据的 device <I2ENo5?
USE master .9r85
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 7TI6EKr
--- 开始 备份 B/;'D7i|S
BACKUP DATABASE pubs TO testBack 9;\mq'v%
4、说明:创建新表 wD$UShnm9-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) =O8>[u;
根据已有的表创建新表: }(XKy!G6
A:create table tab_new like tab_old (使用旧表创建新表) 8HZ+r/j
B:create table tab_new as select col1,col2... from tab_old definition only `$6~QLUf
5、说明:删除新表 IoK/ 2Gp
drop table tabname <-N2<sl
6、说明:增加一个列 uifVSf*
Alter table tabname add column col type ,LSiQmV5
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 4$ihnb`DQN
7、说明:添加主键: Alter table tabname add primary key(col) 34N~<-9AY
说明:删除主键: Alter table tabname drop primary key(col) wYV>Qd
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8、说明:创建索引:create [unique] index idxname on tabname(col....) uPYH3<
删除索引:drop index idxname 3Z me?o*bY
注:索引是不可更改的,想更改必须删除重新建。 f{[0;qDJ
9、说明:创建视图:create view viewname as select statement liLhvcd
删除视图:drop view viewname R?9x!@BV
10、说明:几个简单的基本的sql语句 hOj+z?
选择:select * from table1 where 范围 z5~W
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插入:insert into table1(field1,field2) values(value1,value2) f.66N9BHL,
删除:delete from table1 where 范围 :-Py0{s
更新:update table1 set field1=value1 where 范围 N]|>\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! cL03V? }
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排序:select * from table1 order by field1,field2 [desc] rMZuiRz*
总数:select count as totalcount from table1 9^8OIv?m8
求和:select sum(field1) as sumvalue from table1 mK"s*tD
平均:select avg(field1) as avgvalue from table1 to,\n"$~!
最大:select max(field1) as maxvalue from table1 Fzt?M
最小:select min(field1) as minvalue from table1 Xxd]j]
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11、说明:几个高级查询运算词 vDi Opd
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A: UNION 运算符 bJD$!*r\%!
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。 NsM`kZM4H
B: EXCEPT 运算符 b l+g7 g;
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。 k1zK3I&c_
C: INTERSECT 运算符 5dE=M};v
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。 +
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注:使用运算词的几个查询结果行必须是一致的。 ^i!6z2/
12、说明:使用外连接 v0E6i!D/
A、left outer join: Hk h'h"_r
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。 &{+ 0a[rN
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 y5+%8#3
B:right outer join: 66" 6>
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。 8,!Oup
C:full outer join: qz (x
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。 btq4diW
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二、提升 6(4d3}F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6Xm'^T
法一:select * into b from a where 1<>1 v}V[sIs}
法二:select top 0 * into b from a V(DY!f_%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) hEsiAbTyF
insert into b(a, b, c) select d,e,f from b; 1,bE[_
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) ,#&7+e!]>P
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 N8#j|yf
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 51#OlvD
4、说明:子查询(表名1:a 表名2:b) +)e|>
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) (?JdiY/
5、说明:显示文章、提交人和最后回复时间 bDtb6hL
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b fC*cqc~{@
6、说明:外连接查询(表名1:a 表名2:b) -,p=;t#(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @v#P u_
7、说明:在线视图查询(表名1:a ) \i%mokfbc
select * from (SELECT a,b,c FROM a) T where t.a > 1; :Ez,GA k
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 $#u'XyA
select * from table1 where time between time1 and time2 ,bdjk(
select a,b,c, from table1 where a not between 数值1 and 数值2 5h6o}
9、说明:in 的使用方法 h3k>WNT7
select * from table1 where a [not] in ('值1','值2','值4','值6') PzNPwd
10、说明:两张关联表,删除主表中已经在副表中没有的信息 G--X)h-
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]6)u$4X6$
11、说明:四表联查问题: xHJkzI
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 ..... zp1ym}9M
12、说明:日程安排提前五分钟提醒 \P?X`]NwnO
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bG@2f"
13、说明:一条sql 语句搞定数据库分页 tZKw(<am
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 <]LljTm`i
14、说明:前10条记录 $Emu*'
select top 10 * form table1 where 范围 N~mr@rXC
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) uij^tN%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) RLnL9)`W
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 !+^'Ej)z
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 ZqVbNIY
select top 10 * from tablename order by newid() N6}/TbfAR
18、说明:随机选择记录 jj2\;b:a0
select newid() !#O[RS
19、说明:删除重复记录 uy3<2L#.
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) }A24;'}
20、说明:列出数据库里所有的表名 M]/aW
select name from sysobjects where type='U' X4!7/&
21、说明:列出表里的所有的 Rxd4{L
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select name from syscolumns where id=object_id('TableName') )&7.E
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ^Q$OzsEk
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 #T^2=7 w
显示结果: y-1e(:GF
type vender pcs 4r1\&sI$~
电脑 A 1 d)YlD]I
电脑 A 1 x
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光盘 B 2 71c[`h*0{
光盘 A 2 \{lv~I
手机 B 3 Zg(Y$ h\
手机 C 3 vCaN [
23、说明:初始化表table1 L4g%o9G
TRUNCATE TABLE table1 ] [MtG
24、说明:选择从10到15的记录 IFX$\+-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,=m.WmXE
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三、技巧 5h#h>0F
1、1=1,1=2的使用,在SQL语句组合时用的较多 <GNLDpj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LJ(WU)CPc
如: k5.5$<< T
if @strWhere !='' "lL+Heq>V
begin -y+>^45
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere : OY~Q3
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end 'cXdc
else UUJQc~=
begin ilL0=[2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !rM~
end EX`P(=zD
我们可以直接写成 EbQLMLD%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere `S@TiD*
2、收缩数据库 )O~[4xV~
--重建索引 .z`70ot?
DBCC REINDEX s3Vb2C*
DBCC INDEXDEFRAG XWp8[Cxs
--收缩数据和日志 Iv6 q(c
DBCC SHRINKDB (hzN(Dh
DBCC SHRINKFILE ssi7)0
3、压缩数据库 KT(Z
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dbcc shrinkdatabase(dbname) @yaFN>w
4、转移数据库给新用户以已存在用户权限 JF.Lo;
exec sp_change_users_login 'update_one','newname','oldname' c0@8KW[,
go lS.Adl^k
5、检查备份集 c[dzO.~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ]yU"J:/
6、修复数据库 HB/V4ki
ALTER DATABASE [dvbbs] SET SINGLE_USER WVbrbs4
GO Z .6dL
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK hi0HEm\
GO 8vY-bm,e
ALTER DATABASE [dvbbs] SET MULTI_USER >d 2Fa4u3
GO 5~JT*Ny
7、日志清除 H$(bSw$
SET NOCOUNT ON zN4OrG0
DECLARE @LogicalFileName sysname, Ic#xz;elM
@MaxMinutes INT, /fr> Fd
@NewSize INT u]J@65~'b
USE tablename -- 要操作的数据库名 *x"80UXL
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ;Ba%aaHl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. LwH#|8F
@NewSize = 1 -- 你想设定的日志文件的大小(M) rVYoxXv
-- Setup / initialize >1~
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DECLARE @OriginalSize int <$(B [T
SELECT @OriginalSize = size i6`"e[aT[o
FROM sysfiles @p+;iS1}
WHERE name = @LogicalFileName |7s2xRc
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bmfM_oz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + V8?}I)#(7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' K9lgDk"i
FROM sysfiles 'YNaLZ20
WHERE name = @LogicalFileName I &t~o
CREATE TABLE DummyTrans Eah6"j!B8n
(DummyColumn char (8000) not null) OU[<\d
DECLARE @Counter INT, *U?O4E9
@StartTime DATETIME, NB"S,\M0
@TruncLog VARCHAR(255) S\k <
SELECT @StartTime = GETDATE(), e3?=1ZB
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :]^e-p!z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ~&?bU]F
EXEC (@TruncLog) x *Lt]]A
-- Wrap the log if necessary. ff"wg\O4
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %@/^UE:
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) g`7XE
AND (@OriginalSize * 8 /1024) > @NewSize "F<CGSo
BEGIN -- Outer loop.
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SELECT @Counter = 0 Aw o)a8e
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (yOkf-e2y
BEGIN -- update 1o_kY"D<
INSERT DummyTrans VALUES ('Fill Log') BM%wZ:
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DELETE DummyTrans h+ f>#O+:
SELECT @Counter = @Counter + 1 0B
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END xt{'Be&Ya+
EXEC (@TruncLog) +L(amq;S
END &NE e-cb[
SELECT 'Final Size of ' + db_name() + ' LOG is ' + X%1TsCKMj
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + rH+OXGoB
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3FEJ
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FROM sysfiles D6sw"V#
WHERE name = @LogicalFileName k*.]*]
DROP TABLE DummyTrans I2ek`t]
SET NOCOUNT OFF &|>+LP@8
8、说明:更改某个表 24mdhT|
exec sp_changeobjectowner 'tablename','dbo' H"C'<(4*\
9、存储更改全部表 ]n22+]D
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _"DS?`z6
@OldOwner as NVARCHAR(128), 4`IM[DIG~
@NewOwner as NVARCHAR(128) y7R#PkQ~
AS mo0\t#jA
DECLARE @Name as NVARCHAR(128) o\AnM5
DECLARE @Owner as NVARCHAR(128) $`=p]
DECLARE @OwnerName as NVARCHAR(128) f-=\qSo
DECLARE curObject CURSOR FOR :$ 5A3i
select 'Name' = name, gg;r;3u
'Owner' = user_name(uid) E h%61/
from sysobjects 5jdZC(q5a
where user_name(uid)=@OldOwner qtGJJ#^,
order by name J~Xv R
OPEN curObject ] $ew 5%
FETCH NEXT FROM curObject INTO @Name, @Owner [uq>b|`RG
WHILE(@@FETCH_STATUS=0) pMc6p0
BEGIN fCl}eXg6w
if @Owner=@OldOwner ]Z JoC!u
begin DHidI\*gT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) (JhX:1
exec sp_changeobjectowner @OwnerName, @NewOwner N0U/u'J!g
end #Ondhy%h[
-- select @name,@NewOwner,@OldOwner )Nv1_en<!
FETCH NEXT FROM curObject INTO @Name, @Owner VSj!Gm0LB
END ~xH&"1
close curObject +Q*`kg'
deallocate curObject 7p&jSOY
GO XX;4A
10、SQL SERVER中直接循环写入数据 30Yis_l2h
declare @i int bdUPo+
set @i=1 "}]`64?
while @i<30 # kI>
begin R#(0C(FI^
insert into test (userid) values(@i) F /b`[
set @i=@i+1 X>%nzY]m
end W+XWS,(
小记存储过程中经常用到的本周,本月,本年函数 7\u+%i;YZ
Dateadd(wk,datediff(wk,0,getdate()),-1) zd?@xno
Dateadd(wk,datediff(wk,0,getdate()),6) J(
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Dateadd(mm,datediff(mm,0,getdate()),0) @u3`lhUcT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ^6 6!f 5^W
Dateadd(yy,datediff(yy,0,getdate()),0) 'nJF:+30ZH
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) aD/Rr3v>
上面的SQL代码只是一个时间段 LzygupxY!
Dateadd(wk,datediff(wk,0,getdate()),-1) ^\)a[OWp
Dateadd(wk,datediff(wk,0,getdate()),6) HDyf]2N*N
就是表示本周时间段. -DDA b(2*
下面的SQL的条件部分,就是查询时间段在本周范围内的: xVvUx,t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0oe<=L]F
而在存储过程中 .{Y;6]9[
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]wQ!ZG?)
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) v1h(_NLI!