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。 p.)G ],
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一、基础 K@ 6$|.bc
1、说明:创建数据库 t-e:f0iz
CREATE DATABASE database-name dYW19$W
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2、说明:删除数据库 qHklu2_%
drop database dbname UfXqcyY(
3、说明:备份sql server 5yuR[VU
--- 创建 备份数据的 device nx84l 7<
USE master 6*Rz}RQ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Jva&"}Cb
--- 开始 备份 [Cvo^cC
BACKUP DATABASE pubs TO testBack hK3?m.>"g
4、说明:创建新表 J1hc :I<;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Mvu!
根据已有的表创建新表: ]=7}Y%6
A:create table tab_new like tab_old (使用旧表创建新表) u9_ Fjm}&
B:create table tab_new as select col1,col2... from tab_old definition only slXk <
5、说明:删除新表 u+kXJ
drop table tabname a8Nl'
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6、说明:增加一个列 eE+zL~CE
Alter table tabname add column col type 4cl}ouG
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。 ]&jXD=a"
7、说明:添加主键: Alter table tabname add primary key(col) |s+y]3-_
说明:删除主键: Alter table tabname drop primary key(col) C&D!TR!K
8、说明:创建索引:create [unique] index idxname on tabname(col....) RKx"
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删除索引:drop index idxname YOd0dKe
注:索引是不可更改的,想更改必须删除重新建。 Yc&yv
9、说明:创建视图:create view viewname as select statement 9ssTG4Sa
删除视图:drop view viewname ">j}!n
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10、说明:几个简单的基本的sql语句 <%Bsb}h,
选择:select * from table1 where 范围 9Y3_.qa(.
插入:insert into table1(field1,field2) values(value1,value2) c\065#f!
删除:delete from table1 where 范围 >iDV8y
更新:update table1 set field1=value1 where 范围 `a*[@a#
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $b
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排序:select * from table1 order by field1,field2 [desc] N[~RWg
总数:select count as totalcount from table1 )\8l6Gw
求和:select sum(field1) as sumvalue from table1 /z.Y<xOc
平均:select avg(field1) as avgvalue from table1 bODCC5yL
最大:select max(field1) as maxvalue from table1 [8v v[n/
最小:select min(field1) as minvalue from table1 sFsp`kf
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11、说明:几个高级查询运算词 Mpzt9*7R
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A: UNION 运算符 gG!L#J?
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 c_"]AhV~Mg
B: EXCEPT 运算符 9LI#&\lba
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 |7LhE+E
C: INTERSECT 运算符 .Ks%ar
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 L'iENZI$
注:使用运算词的几个查询结果行必须是一致的。 tURjIt,I
12、说明:使用外连接 j'R{llZW
A、left outer join: kI<;rP1S|
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。 n6Je5fE
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 i 3?=up!
B:right outer join: N =FX3Z
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。 <b.?G
C:full outer join: JK))Cuh
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。 ;'~U5Po8
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二、提升 d"`/P?nx
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?Z9C}t]
法一:select * into b from a where 1<>1 _bRd2k,
法二:select top 0 * into b from a DO`
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^K.
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insert into b(a, b, c) select d,e,f from b; Up*1j:_O
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) ND $m|V-C
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 I|8'#QX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^yL6A1
4、说明:子查询(表名1:a 表名2:b) '#LbIv4
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) R/Y9t8kk
5、说明:显示文章、提交人和最后回复时间 n;+CV~
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b R9@Dd
6、说明:外连接查询(表名1:a 表名2:b) E%8Op{zv_
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'na{"
7、说明:在线视图查询(表名1:a ) $a.fQ<,\X
select * from (SELECT a,b,c FROM a) T where t.a > 1; k<(G)7'gm
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 HI&N&a9C
select * from table1 where time between time1 and time2 xMsSZ{j%5
select a,b,c, from table1 where a not between 数值1 and 数值2 (cAWT,
9、说明:in 的使用方法 50kjX}
select * from table1 where a [not] in ('值1','值2','值4','值6') gT8Q:8f:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 z=%&?V
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :59fb"^$
11、说明:四表联查问题: ;\-f7!s
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 ..... OCHjQc
12、说明:日程安排提前五分钟提醒 Bu7Ztt*
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Kcf1$`F24
13、说明:一条sql 语句搞定数据库分页 J< Ljg<t+
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 goBl~fqy0
14、说明:前10条记录 IC"lsNq52
select top 10 * form table1 where 范围 r:;nv D
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.) 2MY-9(no
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) F/O5Z?C?
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 &BTgISYi
(select a from tableA ) except (select a from tableB) except (select a from tableC) i82sMN1jl7
17、说明:随机取出10条数据 9BR/zQ2
select top 10 * from tablename order by newid() R. :~e
18、说明:随机选择记录 $.HZz
select newid() ^#i3JMq
19、说明:删除重复记录 9lXjB_wG>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) B\^myg4
20、说明:列出数据库里所有的表名 VgGMlDl
select name from sysobjects where type='U' ^EtBo7^t
21、说明:列出表里的所有的 v<0\+}T1R
select name from syscolumns where id=object_id('TableName') 5>CmWMQ
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 (B+CI%=
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 4f~ c#0?
显示结果: "-
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type vender pcs WX~:Y,l+u
电脑 A 1 ]]Bqte
电脑 A 1 l$_q#Kd
光盘 B 2 OeMI
光盘 A 2 vX?MB
手机 B 3 Lsu_f'p0
手机 C 3 >%6a$r~@
23、说明:初始化表table1 ]cQYSN7!SY
TRUNCATE TABLE table1 fG dT2}gd
24、说明:选择从10到15的记录 mv1g2f+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc JJC YM
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三、技巧 oyw*Z_ 9~
1、1=1,1=2的使用,在SQL语句组合时用的较多 a%nksuP3
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n1XJuc~
如: mH`K~8pRg
if @strWhere !='' l 7T@<V
begin j(xVbUa
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Budo9z_w
end mM#[XKOC<
else 6&9}M Oc
begin `|uwR5
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;D8175px;
end &[yW}uV<7
我们可以直接写成 7=3'PfS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |-)2 D=P
2、收缩数据库 3[{RH*nHD
--重建索引 *C~$<VYI
DBCC REINDEX mv,p*0
DBCC INDEXDEFRAG n3z]&J5fr
--收缩数据和日志 Z-U-n/6I
DBCC SHRINKDB wn1` 9
DBCC SHRINKFILE qX9x#92
3、压缩数据库 L.ML0H-
dbcc shrinkdatabase(dbname) ^WF/gup\hS
4、转移数据库给新用户以已存在用户权限 Q$bi:EyJXc
exec sp_change_users_login 'update_one','newname','oldname' I@/s&$H`l
go Sgp1p}
5、检查备份集 tRZA`&
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' fvE:'( #?
6、修复数据库 n=F|bW
ALTER DATABASE [dvbbs] SET SINGLE_USER OK] _.v}
GO rbt/b0ET
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?zpN09e
GO 6lAHB*`
ALTER DATABASE [dvbbs] SET MULTI_USER 'G)UIjl
GO QJ4=*tX)
7、日志清除 ztEM>xsk
SET NOCOUNT ON _8 C:Md`
DECLARE @LogicalFileName sysname, 5jNDr`pnu
@MaxMinutes INT, %|izt/B
@NewSize INT 0Z4o3r[
USE tablename -- 要操作的数据库名 fW3awR{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 P:OI]x4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ).$q9G
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,&F4|{
-- Setup / initialize sx^0*h-Qq
DECLARE @OriginalSize int -dyN
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SELECT @OriginalSize = size Bj`ZH~T
FROM sysfiles F1A7l"X]
WHERE name = @LogicalFileName CT0 ~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + a%YohfsY?U
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + lKSd]:3Xm
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S_ER^Pkg
FROM sysfiles $S'~UbmYU
WHERE name = @LogicalFileName X,mqQ7+
CREATE TABLE DummyTrans UFl+|wf
(DummyColumn char (8000) not null) 5H^"
DECLARE @Counter INT, !Y,*Zc$R
@StartTime DATETIME, &:?2IAe
@TruncLog VARCHAR(255) A(@VjXl
SELECT @StartTime = GETDATE(), `#3FvP@&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "o}}[hRP
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =}K"@5J
EXEC (@TruncLog) Q<O(Ix
-- Wrap the log if necessary. &YOks.k
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7#[8td
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *l.tsICmbP
AND (@OriginalSize * 8 /1024) > @NewSize @,Kl"i;
BEGIN -- Outer loop. |*5HNP
SELECT @Counter = 0 efrVF5,y?
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) x T8pwTO
BEGIN -- update (x!Tb2mlk
INSERT DummyTrans VALUES ('Fill Log') ;r3Xh)k;
DELETE DummyTrans <$@*'i^7Ez
SELECT @Counter = @Counter + 1 U][\|8i
END oYR OGU
EXEC (@TruncLog) 3/s" ;Kg,
END Wz+7CRpeP
SELECT 'Final Size of ' + db_name() + ' LOG is ' + W lHK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nXJG4$G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0nsj ihw
FROM sysfiles FQe82tfV+
WHERE name = @LogicalFileName i$gH{wn\`
DROP TABLE DummyTrans $'%.w|MJp
SET NOCOUNT OFF 7GDrH/yK
8、说明:更改某个表 jnIf(a
exec sp_changeobjectowner 'tablename','dbo' %f1>cO9[
9、存储更改全部表 .H#<yPty
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch UAEu.AT
@OldOwner as NVARCHAR(128), UlQS]f~
@NewOwner as NVARCHAR(128) tDQuimYu7
AS ]9PQKC2&
DECLARE @Name as NVARCHAR(128) Me2qOc^Z-
DECLARE @Owner as NVARCHAR(128) sL!+&Id|
DECLARE @OwnerName as NVARCHAR(128) ',bSJ4)Y
DECLARE curObject CURSOR FOR zPc kM)
select 'Name' = name, '`sZo1x%f
'Owner' = user_name(uid) <HB@j}qi
from sysobjects f >$V:e([
where user_name(uid)=@OldOwner R5& R~1N
order by name uA;vW\fHr
OPEN curObject [ f;o3
FETCH NEXT FROM curObject INTO @Name, @Owner :d=:>_[
WHILE(@@FETCH_STATUS=0) 11YpC;[o
BEGIN >_|$7m.?n[
if @Owner=@OldOwner <44A*ux
begin /C
set @OwnerName = @OldOwner + '.' + rtrim(@Name) gZ@z}CIw'
exec sp_changeobjectowner @OwnerName, @NewOwner T)o>U&KNP
end 6-Id{m x
-- select @name,@NewOwner,@OldOwner wfQ^3HL
FETCH NEXT FROM curObject INTO @Name, @Owner *O'`&J
END H&SoVi_V
close curObject )>;V72
deallocate curObject `e4gneQY
GO (sqI:a
10、SQL SERVER中直接循环写入数据 >/.w80<'
declare @i int vHXCT?FuG
set @i=1 mlix^P
while @i<30 tA8O(9OV
begin .R]DT5
insert into test (userid) values(@i) %:}o\ _w
set @i=@i+1 p(6KJK\
end v3b+Ddp
小记存储过程中经常用到的本周,本月,本年函数 bbs'>D3
Dateadd(wk,datediff(wk,0,getdate()),-1) Ctx`b[&KXX
Dateadd(wk,datediff(wk,0,getdate()),6) xG WA5[YV
Dateadd(mm,datediff(mm,0,getdate()),0) (v}4,'dS
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) i]15g@
Dateadd(yy,datediff(yy,0,getdate()),0) ./35_Vy/O
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5tl($j
上面的SQL代码只是一个时间段 \:4SN&I~
Dateadd(wk,datediff(wk,0,getdate()),-1) n7/>+V+
Dateadd(wk,datediff(wk,0,getdate()),6) Hu$y8_Udw
就是表示本周时间段. <DZ$"t
下面的SQL的条件部分,就是查询时间段在本周范围内的: TW6F9}'f&
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M(?0c}z
而在存储过程中 X?U'GLm
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) yoH,4,! G
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) e}+Zj'5