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。 E]v?:!!ds
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一、基础 JfY(};&
1、说明:创建数据库 I{h KN V
CREATE DATABASE database-name ,"Fl/AjO
2、说明:删除数据库 Y'5(exW
drop database dbname 3-&~jm~"
3、说明:备份sql server #uF`|M$u
--- 创建 备份数据的 device ~sZ$`t
USE master y+Hz(}4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' cK >^8T^
--- 开始 备份 =Z{jc
BACKUP DATABASE pubs TO testBack $s4.Aj
4、说明:创建新表 @meT8S9t
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) qZ4))X
根据已有的表创建新表: >JAWcT)d
A:create table tab_new like tab_old (使用旧表创建新表) &_u.q/~
B:create table tab_new as select col1,col2... from tab_old definition only ALV(fv$cD
5、说明:删除新表 ,i1BoG
drop table tabname Oi zj|'
6、说明:增加一个列 ;rF[y7\
Alter table tabname add column col type f%i%QZP
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。 Ctn
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7、说明:添加主键: Alter table tabname add primary key(col) z:$ibk4#h
说明:删除主键: Alter table tabname drop primary key(col) hO&_VCk
8、说明:创建索引:create [unique] index idxname on tabname(col....) TEh.?
删除索引:drop index idxname $8xb|S[
注:索引是不可更改的,想更改必须删除重新建。 h!v<J
9、说明:创建视图:create view viewname as select statement ]Vmo>
删除视图:drop view viewname -cijLlz%+
10、说明:几个简单的基本的sql语句 zhm 0J-g
选择:select * from table1 where 范围 m[KmXPFht1
插入:insert into table1(field1,field2) values(value1,value2) c#>(8#'.U
删除:delete from table1 where 范围 vS)>g4
更新:update table1 set field1=value1 where 范围 $dXx@6fP
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %B( rW?p&
排序:select * from table1 order by field1,field2 [desc] P%H Dz
总数:select count as totalcount from table1 Fe4>G8uuwn
求和:select sum(field1) as sumvalue from table1 Mm(#N/
平均:select avg(field1) as avgvalue from table1 %1:caa@_p
最大:select max(field1) as maxvalue from table1 UfPHV%Wd
最小:select min(field1) as minvalue from table1 El@*Fo
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11、说明:几个高级查询运算词 /s~S\dG
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A: UNION 运算符 HFI0\*xn(
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 g&85L$
B: EXCEPT 运算符 B~7!v${
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。 } ck<R
C: INTERSECT 运算符 vsZ?cd
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。 }{VOy PG
注:使用运算词的几个查询结果行必须是一致的。 \Dy|}LE
12、说明:使用外连接 PCHspe9!y
A、left outer join: )Z:D}r8[
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。 W>i"p~!
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 /.<v,CR
B:right outer join: U: Wet,
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。 YcX\t6VK
C:full outer join: 4l%1D.3-O
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。 /1v9U|j
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二、提升 Zi.' V
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) BjsT 9?6W/
法一:select * into b from a where 1<>1 fO&`A:JY
法二:select top 0 * into b from a WA"~6U*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) TKv!wKI
insert into b(a, b, c) select d,e,f from b; uBa<5YDF
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) N{S) b
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 p/?o^_s
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 3_Xu3hNH!
4、说明:子查询(表名1:a 表名2:b) >>,G3/Zd*
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) d_M+W@{
5、说明:显示文章、提交人和最后回复时间 w\YS5!P,V
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b UJSIbb5
6、说明:外连接查询(表名1:a 表名2:b) 8ZVQM7O
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Bskp&NV':
7、说明:在线视图查询(表名1:a ) Tk4>Jb
select * from (SELECT a,b,c FROM a) T where t.a > 1; Lr D@QBT
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 Leb|YX
select * from table1 where time between time1 and time2 w+R7NFq
select a,b,c, from table1 where a not between 数值1 and 数值2 5C9b*]-#
9、说明:in 的使用方法 NeG`D'
select * from table1 where a [not] in ('值1','值2','值4','值6') NFZ(*v1U
10、说明:两张关联表,删除主表中已经在副表中没有的信息 j*G: 8Lg
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) gK`w|kh`
11、说明:四表联查问题: ,M;9|kE*
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 ..... o~IAZU39
12、说明:日程安排提前五分钟提醒 nYjrEy)Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e))L&s
13、说明:一条sql 语句搞定数据库分页 ;_e9v,
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 5M~{MdF|.
14、说明:前10条记录 `a4&_`E,p
select top 10 * form table1 where 范围 5b7(^T^K
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.) kFWwz^x
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {h7 vJ^
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 3W%6n-*u
(select a from tableA ) except (select a from tableB) except (select a from tableC) eKvr1m- -
17、说明:随机取出10条数据 0_gN]>,9n
select top 10 * from tablename order by newid() )*;Tt @'y
18、说明:随机选择记录 **Ioy+
select newid() hr
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19、说明:删除重复记录 GXVx/)H
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) vTO9XHc E
20、说明:列出数据库里所有的表名 );7
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select name from sysobjects where type='U' [~s+,OO9)
21、说明:列出表里的所有的 QDg5B6>$
select name from syscolumns where id=object_id('TableName') @@Ybg6.+*
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。 N3|:MMl
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 A_zCSRF,
显示结果: BB/wL_=:
type vender pcs i D IY|
电脑 A 1 1@}F8&EZ
电脑 A 1 <|}Z6Ti
光盘 B 2 `Npa/Q
光盘 A 2 xo_STLAw
手机 B 3 rMDvnF
手机 C 3 rF-SvSj}
23、说明:初始化表table1 T>&
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TRUNCATE TABLE table1 2{rWAPHgz
24、说明:选择从10到15的记录 $72eHdy/yl
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc vPNbV
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三、技巧 x|rc[e%k
1、1=1,1=2的使用,在SQL语句组合时用的较多 lmzHE8MUNu
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1'E=R0`pA
如: $*#^C;7O
if @strWhere !='' )4
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begin [<RhaZz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere d&FXndC4F
end NZvgkci_(u
else &)1.z7T
begin sN[}B{+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ay?<~)H
end rv*{[K
我们可以直接写成 2X@9o4_4q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |IcW7(
2、收缩数据库 ?}cmES kX@
--重建索引 ,<rC,4-F<
DBCC REINDEX h+Co:pr
DBCC INDEXDEFRAG Z@0tZ^V{
--收缩数据和日志 Zd[rn:9\
DBCC SHRINKDB _`udd)Y2
DBCC SHRINKFILE t{]Ew4Y4%O
3、压缩数据库 OTXZdAv
dbcc shrinkdatabase(dbname) Ib# -M;{
4、转移数据库给新用户以已存在用户权限 _nMd
exec sp_change_users_login 'update_one','newname','oldname' 9Y:I)^ek
go 3x+lf4"
5、检查备份集 0Qt!w(
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' R5uG.Oj-2
6、修复数据库 bw P=f.
ALTER DATABASE [dvbbs] SET SINGLE_USER %;'~TtW5
GO t`Z'TqP R
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK %GhI0F #
GO 'Cc~|gOgD
ALTER DATABASE [dvbbs] SET MULTI_USER YhN<vZ}U!~
GO Z=a%)Ki?Ag
7、日志清除 S0^a)#D &
SET NOCOUNT ON J\@6YU[A
DECLARE @LogicalFileName sysname, d+q],\"R
@MaxMinutes INT, duY?LJ @g
@NewSize INT {cXr!N^K
USE tablename -- 要操作的数据库名 &>JP.//spi
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 |(>`qL{|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. xnZnbgO+
@NewSize = 1 -- 你想设定的日志文件的大小(M) )zr*Ecz
-- Setup / initialize =NF0E8O
DECLARE @OriginalSize int #rkq
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SELECT @OriginalSize = size 'C'mgEl%L
FROM sysfiles qIi
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WHERE name = @LogicalFileName _i05'_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + PILpWhjL$9
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + f$C{Z9_SX
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' EqW~K@
FROM sysfiles 1+FVM\<&
WHERE name = @LogicalFileName q?}C`5%D
CREATE TABLE DummyTrans k[r^@|
(DummyColumn char (8000) not null) Lnh=y2
DECLARE @Counter INT, >C|pY6
@StartTime DATETIME, 2RkW/)A9
@TruncLog VARCHAR(255) ~1uQyt
SELECT @StartTime = GETDATE(), >yC=@Uq+
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' tMxde+$y
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ZxF`i>/h
EXEC (@TruncLog) (P|[<Sd
-- Wrap the log if necessary. G4cgY|71
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired U~x]2{}
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <\&9Odqc
AND (@OriginalSize * 8 /1024) > @NewSize TR DQ+Z
BEGIN -- Outer loop. EF`}*7)
SELECT @Counter = 0 u} ot-!}Q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) dQ`Tt- n
BEGIN -- update =:]ps<Qx
INSERT DummyTrans VALUES ('Fill Log') hne@I1
DELETE DummyTrans b>uD-CSA
SELECT @Counter = @Counter + 1 (;{X-c}?
END z?o8h
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EXEC (@TruncLog) X8)k'h
END 4IeCb?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + =)Xj[NNRT
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + g:Hj1!'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6("_}9ZOc
FROM sysfiles ?:"ABkL|+Y
WHERE name = @LogicalFileName 6
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DROP TABLE DummyTrans h&0zR#t
SET NOCOUNT OFF cC/h7odY
8、说明:更改某个表 jWrU'X
exec sp_changeobjectowner 'tablename','dbo' X)b$CG
9、存储更改全部表 P[3i!"O>
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 25SWIpgG
@OldOwner as NVARCHAR(128), eAy,T<#
@NewOwner as NVARCHAR(128) c{M
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AS =-U0r$sK+F
DECLARE @Name as NVARCHAR(128) sO.MUj;
DECLARE @Owner as NVARCHAR(128) gm9*z.S\'
DECLARE @OwnerName as NVARCHAR(128) &K/?#
DECLARE curObject CURSOR FOR i7Qb~RW
select 'Name' = name, KQ\K:#
'Owner' = user_name(uid) QG5WsuT
from sysobjects <*(Z}p
where user_name(uid)=@OldOwner EvT$|#FY
order by name o[ 5dR<
OPEN curObject MmT/J1zM
FETCH NEXT FROM curObject INTO @Name, @Owner oZBD.s
WHILE(@@FETCH_STATUS=0) ^ij0<*ca9
BEGIN *9'3 `^l
if @Owner=@OldOwner @:>"VP<(
begin @]Cg5QW>T
set @OwnerName = @OldOwner + '.' + rtrim(@Name) u$T]A8e
exec sp_changeobjectowner @OwnerName, @NewOwner U=n7RPw
end <,} h8;Fr
-- select @name,@NewOwner,@OldOwner RjWwsC~B
FETCH NEXT FROM curObject INTO @Name, @Owner Q %o@s3~O
END {-Y;!
close curObject :iE b^F}
deallocate curObject @](vFb
GO !T0I; j&
10、SQL SERVER中直接循环写入数据 N>I6f
declare @i int :HY$x
set @i=1 Q#eMwM#~
while @i<30 T[\1=h]
begin &L8RLSfX
insert into test (userid) values(@i) t1 3V>9to
set @i=@i+1 1:-'euA"
end H*W>v[>
小记存储过程中经常用到的本周,本月,本年函数 2zC4nF)>O
Dateadd(wk,datediff(wk,0,getdate()),-1) Ta?J;&<u]/
Dateadd(wk,datediff(wk,0,getdate()),6) ] ?DU8
Dateadd(mm,datediff(mm,0,getdate()),0) m{q'RAw
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) (:l6R9'=
Dateadd(yy,datediff(yy,0,getdate()),0) 5Tl5T&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) EX]+e
上面的SQL代码只是一个时间段 a'VQegP(f\
Dateadd(wk,datediff(wk,0,getdate()),-1) :kgh~mx5LF
Dateadd(wk,datediff(wk,0,getdate()),6) xi (@\A
就是表示本周时间段. -xtT,^<B
下面的SQL的条件部分,就是查询时间段在本周范围内的: Df6i*Ko|
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) OUBGbld
而在存储过程中 D3Q+K
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) &N}"4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) e9LX0=