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。 _7#9nJ3|
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一、基础 "GTlJqhk
1、说明:创建数据库 A=(<g";m
CREATE DATABASE database-name VT;Vm3\
2、说明:删除数据库 *x;&fyR
drop database dbname +@ FM~q
3、说明:备份sql server []v t\I
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--- 创建 备份数据的 device *&d>Vk."]
USE master /ehmy(zL
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^J
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--- 开始 备份 [K\Vc9
BACKUP DATABASE pubs TO testBack ~'[0-_]=f
4、说明:创建新表 m4<5jC`-M
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [f?fA[,[
根据已有的表创建新表: X(`wj~45VX
A:create table tab_new like tab_old (使用旧表创建新表) r ^m8kYezQ
B:create table tab_new as select col1,col2... from tab_old definition only `k 5'nnyP
5、说明:删除新表 J ^y1=PM
drop table tabname fnwhkL#8
6、说明:增加一个列 ~q.a<B`,t
Alter table tabname add column col type 9uNkd2#
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。 L>&o_bzp
7、说明:添加主键: Alter table tabname add primary key(col) Qrnc;H9)
说明:删除主键: Alter table tabname drop primary key(col) !Rq.L
8、说明:创建索引:create [unique] index idxname on tabname(col....) v|WT m#
删除索引:drop index idxname [T(XwA)
注:索引是不可更改的,想更改必须删除重新建。 7H+IW4Ma
9、说明:创建视图:create view viewname as select statement ?51Y&gOEZ
删除视图:drop view viewname !6R;fD#^s
10、说明:几个简单的基本的sql语句 "zn<\z$l
选择:select * from table1 where 范围 \%qzTk.&r
插入:insert into table1(field1,field2) values(value1,value2) TspuZR@2
删除:delete from table1 where 范围 su/!<y
更新:update table1 set field1=value1 where 范围 .}wVM`81z
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g p2S
排序:select * from table1 order by field1,field2 [desc] 2+2Gl7" s
总数:select count as totalcount from table1 bI_6';hq!
求和:select sum(field1) as sumvalue from table1 )dv w.X
平均:select avg(field1) as avgvalue from table1 S^Lu RF]F
最大:select max(field1) as maxvalue from table1 rW8.bMmM
最小:select min(field1) as minvalue from table1 *Va ;ra(V2
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11、说明:几个高级查询运算词 eNwF<0}
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A: UNION 运算符 .d JX,^
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。 GV+K]
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B: EXCEPT 运算符 kgq"b)
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。 y.O%
C: INTERSECT 运算符 <?Z [X{
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。 \ r^#a
注:使用运算词的几个查询结果行必须是一致的。 *[P"2b#
12、说明:使用外连接 zA
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A、left outer join: \I@hDMqv
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。 / bxu{|.
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 &y7<h>z
B:right outer join: e;*GbXd|
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。 4P406,T]r
C:full outer join: 6ka,
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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。 4dEfXrMf
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二、提升 k3HPY}-
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) pQ_EJX)
法一:select * into b from a where 1<>1 B#+0jdF;
法二:select top 0 * into b from a o#D;H[' A
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Mx7
insert into b(a, b, c) select d,e,f from b; va`/Dp)M
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) M/O
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 uuD|%-Ng
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. DFk0"+Ky
4、说明:子查询(表名1:a 表名2:b) m=qEQy6#2u
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) ho'Ihep,L
5、说明:显示文章、提交人和最后回复时间 L<}0}y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ^Uj\s /
6、说明:外连接查询(表名1:a 表名2:b) *&=sL
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c u . xUM
7、说明:在线视图查询(表名1:a ) W<QMUu
select * from (SELECT a,b,c FROM a) T where t.a > 1; q)m0n237P
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 RjcU0$Hi
select * from table1 where time between time1 and time2 /:+f5\"-b
select a,b,c, from table1 where a not between 数值1 and 数值2 fLtN-w6t
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') Z7="on4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 \Nvu[P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }MCh$
11、说明:四表联查问题: 1(q&(p
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 ..... Z8Jrt3l{2
12、说明:日程安排提前五分钟提醒 )wt mc4'
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 R7nT,7k.
13、说明:一条sql 语句搞定数据库分页 '4"9f]:
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 `X:o]t@
14、说明:前10条记录 } xy>uT
select top 10 * form table1 where 范围 FQ3{~05T
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.) |[ )e5Xhd
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (uxe<'Co|
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 sa7F-XM
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2`[iTBZ=^
17、说明:随机取出10条数据 1 iiQW
select top 10 * from tablename order by newid() 7 K5D,"D;1
18、说明:随机选择记录 9GV1@'<Y]
select newid() Qf>$'C(7!a
19、说明:删除重复记录 'o!{YLJ fM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _x2i=SFo*$
20、说明:列出数据库里所有的表名 ,Vc>'4E-
select name from sysobjects where type='U' I<``d Ne9Q
21、说明:列出表里的所有的 Bh#?:h&f
select name from syscolumns where id=object_id('TableName') *\n-yx]
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。 h:4Uv}Z
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 Bp7`W:?#"
显示结果: YV{^2)^
type vender pcs WLy%|{/
电脑 A 1 +=V[7^K;
电脑 A 1 vGX}zzto
光盘 B 2 ]SO-NR
光盘 A 2 MyJ\/` 8
手机 B 3 ?_@_NV MY
手机 C 3 BM
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23、说明:初始化表table1 ^?~WIS
TRUNCATE TABLE table1
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24、说明:选择从10到15的记录 #hQ#_7
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ld7B!_b<
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三、技巧 cm'`u&S
1、1=1,1=2的使用,在SQL语句组合时用的较多 DO^J=e
"where 1=1" 是表示选择全部 "where 1=2"全部不选, GBvgVX<
如: ROWI.|
if @strWhere !='' TdCC,/c3
begin B1U<m=Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere QMz6syn4u
end vg"$&YX9"
else g0Ff$-#7
begin :kU-ol$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' *6`};ASK
end BKV,V/*p
我们可以直接写成 .XVW2ISv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere it#,5#Y:
2、收缩数据库 \ ";^nk*
--重建索引 gB)Cmw*
DBCC REINDEX k vQ]
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DBCC INDEXDEFRAG PsMp&~^
--收缩数据和日志 0DsW1
DBCC SHRINKDB jR_o!n~5
DBCC SHRINKFILE #$^vP/"$
3、压缩数据库 Qf
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dbcc shrinkdatabase(dbname) yU{Q`6u T
4、转移数据库给新用户以已存在用户权限 <NYf !bx
exec sp_change_users_login 'update_one','newname','oldname' v]?zG&Jh
go "G[yV>pxv
5、检查备份集 %`# HGji)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ]Uu :t
6、修复数据库 6/=0RTd
ALTER DATABASE [dvbbs] SET SINGLE_USER b)(rlX
GO d$gT,+|vu
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $SbgdbX
GO nkxv,_)ZT
ALTER DATABASE [dvbbs] SET MULTI_USER <Crbc$!OeX
GO F*, e,s
7、日志清除 GL^84[f-T
SET NOCOUNT ON #1z/rUh`Cr
DECLARE @LogicalFileName sysname, T1\@4x
@MaxMinutes INT, yW)&jZb"(
@NewSize INT 99YgQ Y]HO
USE tablename -- 要操作的数据库名 {2v,J]v_[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ds<~JfVl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !j8
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@NewSize = 1 -- 你想设定的日志文件的大小(M) LZI[5tA "
-- Setup / initialize `Q!#v{
DECLARE @OriginalSize int Oj,v88=
SELECT @OriginalSize = size ?heg_~P
FROM sysfiles [a[.tR38e
WHERE name = @LogicalFileName b$JrLZs$_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6>Z)w}x^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N87)rhXSo,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ;ipT0*Y
FROM sysfiles #WlTE&
WHERE name = @LogicalFileName nSr_sD6"
CREATE TABLE DummyTrans gtwUY$
(DummyColumn char (8000) not null) {y%cTuC=
DECLARE @Counter INT, '5r\o8RjN
@StartTime DATETIME, ^B!cL~S*I
@TruncLog VARCHAR(255) )#Le"&D
SELECT @StartTime = GETDATE(), 8-&c%h
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' hqW),^\>'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (Zz8 ldO
EXEC (@TruncLog) bP)(4+t~
-- Wrap the log if necessary. RA$%3L[A!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired c2RQwtN|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) xh:A*ZI=7
AND (@OriginalSize * 8 /1024) > @NewSize dI?x(vw
BEGIN -- Outer loop. Fxx-2(U
SELECT @Counter = 0 PY76;D*`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) tu:W1?
BEGIN -- update $}8@?>-w
INSERT DummyTrans VALUES ('Fill Log') gjL+8Rk
DELETE DummyTrans 0CpE,gg
SELECT @Counter = @Counter + 1 =fcM2O#$
END v
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EXEC (@TruncLog) Xx+eGV";`
END (&!RX.i
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ial"nV0>0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Kn*LwWne
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5kik+
FROM sysfiles &Sdf0"
WHERE name = @LogicalFileName [C`LKA$t
DROP TABLE DummyTrans <]f{X<ef
SET NOCOUNT OFF cw/E?0MWb
8、说明:更改某个表 qO RL
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exec sp_changeobjectowner 'tablename','dbo' Ly q[gQjr
9、存储更改全部表 Eyq4w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~$jRn(2
@OldOwner as NVARCHAR(128), V.-cm51I
@NewOwner as NVARCHAR(128)
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AS =eyPo(B
DECLARE @Name as NVARCHAR(128) g-4j1yJV<
DECLARE @Owner as NVARCHAR(128) JI[{n~bhGD
DECLARE @OwnerName as NVARCHAR(128) z)ndj
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DECLARE curObject CURSOR FOR @gnLY
select 'Name' = name, jR2^n`D
'Owner' = user_name(uid) O~#A )d6
from sysobjects HV=P!v6
where user_name(uid)=@OldOwner 1$)}EL
order by name &d_2WQ}
OPEN curObject sH.,O9'r
FETCH NEXT FROM curObject INTO @Name, @Owner G$[Hm\V
WHILE(@@FETCH_STATUS=0) gx.\&W b
BEGIN Yq>K1E|
if @Owner=@OldOwner {_R{gpj'
begin 64qqJmG3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ( _3QZ
exec sp_changeobjectowner @OwnerName, @NewOwner UB,0c)
end gE9x+g
-- select @name,@NewOwner,@OldOwner KU^|T2s%
FETCH NEXT FROM curObject INTO @Name, @Owner :{s0tw>Z
END yioX^`Fc(~
close curObject )4R[C={
deallocate curObject F<4>g+Ag
GO D]twid~OS
10、SQL SERVER中直接循环写入数据 K]&i9`>N
declare @i int fXSuJ<G
set @i=1 u&Yd+');
while @i<30 Z.b?Jzj
begin W1JvLU5L*r
insert into test (userid) values(@i) @:}l a
set @i=@i+1 ! NJGW
end TDX~?>P
小记存储过程中经常用到的本周,本月,本年函数 cI'su?
Dateadd(wk,datediff(wk,0,getdate()),-1) +y^'\KN
Dateadd(wk,datediff(wk,0,getdate()),6) /5X_gjOL,
Dateadd(mm,datediff(mm,0,getdate()),0) #wZbG|%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >eWORf>7
Dateadd(yy,datediff(yy,0,getdate()),0) Z^c\M\`7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) c-* *~tb(
上面的SQL代码只是一个时间段 sD$K<nyz
Dateadd(wk,datediff(wk,0,getdate()),-1) N , ,[V
Dateadd(wk,datediff(wk,0,getdate()),6) QYEGiT
就是表示本周时间段. ?-'GbOr!
下面的SQL的条件部分,就是查询时间段在本周范围内的: N%S|Ey@f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) bPIo9clq
而在存储过程中 9
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) QJSi|&Rx&?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @<yY Mo7