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。 18`?t_8g
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一、基础 _ '}UNIL
1、说明:创建数据库 phNv^R+
CREATE DATABASE database-name J4JKAv~3
2、说明:删除数据库 Y`_6Ny="
drop database dbname p3-sEIw}Ru
3、说明:备份sql server EBn7waBS
--- 创建 备份数据的 device -yC},tK
USE master _E1:3N|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' .|rpj&>g
--- 开始 备份 d6Z;\f7[
BACKUP DATABASE pubs TO testBack jKtbGVZ7r
4、说明:创建新表 VfQSfNsi
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5ecqJ
根据已有的表创建新表: uh GL1{
A:create table tab_new like tab_old (使用旧表创建新表) \_+d*hHF~
B:create table tab_new as select col1,col2... from tab_old definition only Bp b_y;E
5、说明:删除新表 sqkPC_;A
drop table tabname K/08F|]a
6、说明:增加一个列 Xf.SJ8G
Alter table tabname add column col type R[9[lQ'vR
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。 5` Q#2
7、说明:添加主键: Alter table tabname add primary key(col) }96^OQPE
说明:删除主键: Alter table tabname drop primary key(col) Q2+e`
8、说明:创建索引:create [unique] index idxname on tabname(col....) /|>z7#?m^
删除索引:drop index idxname |i|>-|`!
注:索引是不可更改的,想更改必须删除重新建。 P>)qN,a
9、说明:创建视图:create view viewname as select statement p{88v3b6
删除视图:drop view viewname }3QEclZr
10、说明:几个简单的基本的sql语句 yYW>)
选择:select * from table1 where 范围 w
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插入:insert into table1(field1,field2) values(value1,value2) UGAP$_j
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删除:delete from table1 where 范围 `M|fwlAJQ
更新:update table1 set field1=value1 where 范围 C`DTPoXN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! O8M;q!)y
排序:select * from table1 order by field1,field2 [desc] 9]|cs
总数:select count as totalcount from table1 @ Gl=1
求和:select sum(field1) as sumvalue from table1 <Nkj)`%5iK
平均:select avg(field1) as avgvalue from table1 T[c;},
最大:select max(field1) as maxvalue from table1 eO*FoN
最小:select min(field1) as minvalue from table1 p-;*K(#X
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11、说明:几个高级查询运算词 pvcD
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A: UNION 运算符 2r\f!m'
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。 VJm).>E3k
B: EXCEPT 运算符 uN'e~X6
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。 Ut0oh
C: INTERSECT 运算符 V+DN<F-
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。 $My%7S/3
注:使用运算词的几个查询结果行必须是一致的。 sN;xHTY
12、说明:使用外连接 g
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A、left outer join: T,5]EHea
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 rBT#Cyl
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c P)Sw`^d
B:right outer join: 0>>tdd7
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ](B+ilr
C:full outer join: >NK*$r8
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。 '(~+
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二、提升 EW|bs#l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) QYDSE
法一:select * into b from a where 1<>1 fyh9U_M);w
法二:select top 0 * into b from a |&3[YZY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) gP?pfFhG
insert into b(a, b, c) select d,e,f from b; a!]'S4JS
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) ([^1gG+>J
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ZI}7#K<9X
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. e'p'{]r<w
4、说明:子查询(表名1:a 表名2:b) (xy/:i".V
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) 'tklz*
5、说明:显示文章、提交人和最后回复时间 `gx_+m^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b F0qGkMs|f
6、说明:外连接查询(表名1:a 表名2:b) r 1n l!
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )Z,O*u*
7、说明:在线视图查询(表名1:a ) g>cp;co9g
select * from (SELECT a,b,c FROM a) T where t.a > 1; COZ<^*=A#p
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 lEh; MJ
select * from table1 where time between time1 and time2 3* 1cCM42
select a,b,c, from table1 where a not between 数值1 and 数值2 j!F5gP-l
9、说明:in 的使用方法 [}|x@
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select * from table1 where a [not] in ('值1','值2','值4','值6') !Qy%sY
10、说明:两张关联表,删除主表中已经在副表中没有的信息 nd}[X[ay
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) w9G (^jS6
11、说明:四表联查问题: pxDkf|*
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 ..... Et}S*!IS
12、说明:日程安排提前五分钟提醒 Se{}OG)
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 /0A9d-Qd<
13、说明:一条sql 语句搞定数据库分页 ]MKW5Kq
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 XShi[7
14、说明:前10条记录 -c{O!z6sX
select top 10 * form table1 where 范围 'S;INs2|->
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.) At@H
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J>y}kzCz
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 8KiG(6*Q
(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 Nawph
select top 10 * from tablename order by newid() $SQUN*/>
18、说明:随机选择记录 6j/g/!9c!
select newid() xf% _HMKc
19、说明:删除重复记录 uB_8P+h7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) H`d595<=i;
20、说明:列出数据库里所有的表名 @y]ek/
select name from sysobjects where type='U' VKqIFM1b
21、说明:列出表里的所有的 _)XQb1]
select name from syscolumns where id=object_id('TableName')
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ,1&Pb %}
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Pqu]?X
显示结果: > mk>VM
type vender pcs (E[c-1s
电脑 A 1 ]Dec/Nnj
电脑 A 1 y(^t &tgjS
光盘 B 2 :7>oFz
光盘 A 2 42]hX9E
手机 B 3 _UI*W&*
手机 C 3 xq$(=WPI
23、说明:初始化表table1 `ECY:3"$KA
TRUNCATE TABLE table1 {%Cb0Zh
24、说明:选择从10到15的记录 Vq-W|<7C=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc <hkSbJF
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三、技巧 CiF(
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, /oL&
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如: Bm"-X:='
if @strWhere !='' nQ*9E|Vx
begin ` `mnk>/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1V
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end .,h>2;f
else ![3 /!
begin <$z6:4uN_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =
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end F+@/ "1c
我们可以直接写成 r+:]lO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Fc&3tw"g
2、收缩数据库 c!0u,6
--重建索引 ml,FBBGq|-
DBCC REINDEX (fA>@5n
DBCC INDEXDEFRAG ,ArHS
--收缩数据和日志 \<ko)I#%
DBCC SHRINKDB atiyQuT6Wh
DBCC SHRINKFILE `uP:UQ9S
3、压缩数据库 Yyx sj9
dbcc shrinkdatabase(dbname) {'8td^JEE
4、转移数据库给新用户以已存在用户权限 YY zUg
exec sp_change_users_login 'update_one','newname','oldname' &L[i"1a
go #7Fdmnu`
5、检查备份集 I=[Ir8};
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' DHq#beN
6、修复数据库 \E(^<Af
ALTER DATABASE [dvbbs] SET SINGLE_USER u4#YZOiY)A
GO ]z#+3DaH
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -1{f(/
GO $-)T
ALTER DATABASE [dvbbs] SET MULTI_USER m]+~F_/
GO /8#e < p
7、日志清除 TMsc5E
SET NOCOUNT ON @cr/&
DECLARE @LogicalFileName sysname, Ij>G7Q*d
@MaxMinutes INT, jn4|gQ
@NewSize INT v<@3&bot
USE tablename -- 要操作的数据库名 Q7.jSL6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 8NkyT_\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. KpBOmXE
@NewSize = 1 -- 你想设定的日志文件的大小(M) XJ!?>)N .
-- Setup / initialize " Tk,
DECLARE @OriginalSize int p*j>s\
SELECT @OriginalSize = size aUF{57,<
FROM sysfiles ~GE|,Np
WHERE name = @LogicalFileName 6gabnW3
SELECT 'Original Size of ' + db_name() + ' LOG is ' + `_k_}9Fr
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %+htA0aX
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' QQ`tSYgex
FROM sysfiles !gJTKQX4
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans xw}rFY$
(DummyColumn char (8000) not null) .i {yW
DECLARE @Counter INT, 3:O|p[2)L
@StartTime DATETIME,
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@TruncLog VARCHAR(255) Q<NQ9lX
SELECT @StartTime = GETDATE(), &xt[w>/i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?0'e_s
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /6rQ.+|).
EXEC (@TruncLog) >k
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-- Wrap the log if necessary. %"cOX
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7;c^*"Ud
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^q_wtuQ
AND (@OriginalSize * 8 /1024) > @NewSize }3,
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BEGIN -- Outer loop. ])G|U A.
SELECT @Counter = 0 ,RDWx
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) <)pPq+
BEGIN -- update n*ROlCxV
INSERT DummyTrans VALUES ('Fill Log') }.(DQwC}1k
DELETE DummyTrans 5t-d+vB
SELECT @Counter = @Counter + 1 #D#kw*c
END ju5o).!bg
EXEC (@TruncLog) wpp!H<')
END Yn$:|$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + E=8GSl/Jx
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + w2!:>8o:
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' e$teh`
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FROM sysfiles DE7y\oO]
WHERE name = @LogicalFileName "N">RjJ"
DROP TABLE DummyTrans U'msHF
SET NOCOUNT OFF >Tjl?CS
8、说明:更改某个表 :ssj7wl :
exec sp_changeobjectowner 'tablename','dbo' </Y(4Xwf=
9、存储更改全部表 }t"K(oamm
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g_n_Qlo
@OldOwner as NVARCHAR(128), R|^bZf^
@NewOwner as NVARCHAR(128) 8KN3|)
AS QgKR=GR6
DECLARE @Name as NVARCHAR(128) H)h^|A/vO
DECLARE @Owner as NVARCHAR(128) *DvX||`&
DECLARE @OwnerName as NVARCHAR(128) g-jg;Ri
DECLARE curObject CURSOR FOR Nmd{C(^o
select 'Name' = name, St(jrZb
'Owner' = user_name(uid) $&qLrKJ
from sysobjects
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where user_name(uid)=@OldOwner r\#nBoo(
order by name 6&5D4
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OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner e`U
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WHILE(@@FETCH_STATUS=0) yY!)2{F+
BEGIN %I9f_5BlT8
if @Owner=@OldOwner z R'EQ
begin 0 'THL%lK
set @OwnerName = @OldOwner + '.' + rtrim(@Name) T`pDjT
exec sp_changeobjectowner @OwnerName, @NewOwner `&.qHw)
end '<vb_8.
-- select @name,@NewOwner,@OldOwner [E%g3>/mt
FETCH NEXT FROM curObject INTO @Name, @Owner .I EHjy\+
END z .\r7
close curObject ]b]J)dDI
deallocate curObject CS(XN>N
GO 6FJ*eWPC
10、SQL SERVER中直接循环写入数据 ,\X! :y~
declare @i int JWaWOk(t=?
set @i=1 '^C
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while @i<30
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begin +."|Y3a
insert into test (userid) values(@i) ?9O#b1f N
set @i=@i+1 T)%6"rPL3!
end livKiX`
小记存储过程中经常用到的本周,本月,本年函数 (J.Z+s$:2
Dateadd(wk,datediff(wk,0,getdate()),-1) pZK 1G
Dateadd(wk,datediff(wk,0,getdate()),6) L1I1SFG
Dateadd(mm,datediff(mm,0,getdate()),0) YlUh|sK7m
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4X*U~}
Dateadd(yy,datediff(yy,0,getdate()),0) &o7PB`(l
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) (3$DUvx7
上面的SQL代码只是一个时间段 ^fe,A=k~1
Dateadd(wk,datediff(wk,0,getdate()),-1) f8SO:ihXL
Dateadd(wk,datediff(wk,0,getdate()),6) IY8<^Q']
就是表示本周时间段. i].E1},%
下面的SQL的条件部分,就是查询时间段在本周范围内的: SPRTJdaC9
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) LC##em=Y
而在存储过程中 J)yg<*/3
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E3Y0@r
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8m=R"
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