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。 pGz 5!d
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一、基础 }C-K0ba7
1、说明:创建数据库 .n$c+{
CREATE DATABASE database-name 4Z8FLA+T,
2、说明:删除数据库 FM$$0}X
drop database dbname jN))|eD0x
3、说明:备份sql server {txW>rZX
--- 创建 备份数据的 device (D2G.R\pr
USE master S$#"bK/p^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' t5O '7x
--- 开始 备份 ?APzb4f^W
BACKUP DATABASE pubs TO testBack pmda9V4
4、说明:创建新表 DO*rVs3'p[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) M3q%(!2
根据已有的表创建新表: kU:ge
A:create table tab_new like tab_old (使用旧表创建新表) tofX.oi+C$
B:create table tab_new as select col1,col2... from tab_old definition only 8XfhXm>~
5、说明:删除新表 3(&k4
drop table tabname dfy]w4ETB
6、说明:增加一个列 0O>T{<
Alter table tabname add column col type mok94XuK)
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。 o3 b=)E
7、说明:添加主键: Alter table tabname add primary key(col) /q1k)4?E
说明:删除主键: Alter table tabname drop primary key(col) _[)f<`!g_V
8、说明:创建索引:create [unique] index idxname on tabname(col....) TAL,(&[s
删除索引:drop index idxname "w7{,HP
注:索引是不可更改的,想更改必须删除重新建。 5Z;iK(>IX
9、说明:创建视图:create view viewname as select statement v']Tusmg
删除视图:drop view viewname Ei>.eXUD5
10、说明:几个简单的基本的sql语句
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选择:select * from table1 where 范围 }H#C<:A
插入:insert into table1(field1,field2) values(value1,value2) _uXb 9
删除:delete from table1 where 范围 C b4.N8
更新:update table1 set field1=value1 where 范围 r+=%Ag
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9'5< b
排序:select * from table1 order by field1,field2 [desc] ?)NgODU
总数:select count as totalcount from table1 --OAsbr
求和:select sum(field1) as sumvalue from table1 ^8.s"4{
平均:select avg(field1) as avgvalue from table1 h`i*~${yg
最大:select max(field1) as maxvalue from table1 n4XEyCrD
最小:select min(field1) as minvalue from table1 u@]rR&h`
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11、说明:几个高级查询运算词 d+qeZGg^A
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A: UNION 运算符 f;D(X/"f]
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 @\U;?N~k
B: EXCEPT 运算符 a``/x_EZMn
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 5J-slNNCQ
C: INTERSECT 运算符 |@W|nbAfX
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 J,G/L!Bp
注:使用运算词的几个查询结果行必须是一致的。 .R^R32ln
12、说明:使用外连接 QXI#gA
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A、left outer join: &3Y "Zd!
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 _xsHU`(J#
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c OYyF*F&S[
B:right outer join: C5,\DdCX,
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 HXm&`
C:full outer join: 3>>Ca;>$
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。 KzZfpdI92
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二、提升 Prc(
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 5Vc~yMz
法一:select * into b from a where 1<>1 0VnRtLnqI
法二:select top 0 * into b from a ZAJ~Tbm[f
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) b{BiC&3
insert into b(a, b, c) select d,e,f from b; V=gu'~
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) (}RTHpD
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 lLur.f
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. f4O}WU}l{s
4、说明:子查询(表名1:a 表名2:b) (I/ZI'Ydy
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) U(+%iD60i
5、说明:显示文章、提交人和最后回复时间 g'+2bQ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b zYxA#TZL
6、说明:外连接查询(表名1:a 表名2:b) BN&eU'Dl]
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ! FVD_8
7、说明:在线视图查询(表名1:a ) RD6>\9
select * from (SELECT a,b,c FROM a) T where t.a > 1; /H?) qk
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 4`Cgz#v
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select * from table1 where time between time1 and time2 I!"/ I8Y
select a,b,c, from table1 where a not between 数值1 and 数值2 !eHQe7_
9、说明:in 的使用方法 5d;(D i5z
select * from table1 where a [not] in ('值1','值2','值4','值6') lSfPOx;*
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9=J 3T66U
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) nt%fJ k
11、说明:四表联查问题: /2Z7
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 ..... a|5<L
12、说明:日程安排提前五分钟提醒 O]XgA0]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 T|&u?
13、说明:一条sql 语句搞定数据库分页 ^V~^[Yp
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 R5i xG9
14、说明:前10条记录 _'|C-j`u$
select top 10 * form table1 where 范围 9ec>#Vxx
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.) z57q|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $a|>>?8
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 !
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(select a from tableA ) except (select a from tableB) except (select a from tableC) 4d_Az'7`4
17、说明:随机取出10条数据 W!+eJ!Da
select top 10 * from tablename order by newid() R2==<"gq
18、说明:随机选择记录 dy ~M5,zn
select newid() ;Kh[6{ W
19、说明:删除重复记录 8%`h:fE
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %J+ w9Z
20、说明:列出数据库里所有的表名 Spw^h=o
select name from sysobjects where type='U' 9!PM1<p
21、说明:列出表里的所有的 "yK)9F[9Mo
select name from syscolumns where id=object_id('TableName') I^)_rOgM
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ?pdN!zOeL
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type bZ#KfR
显示结果: th{ie2$
type vender pcs peew<SX
电脑 A 1 ^jXKM!}-E
电脑 A 1 `46|VQAx
光盘 B 2 S\ K[l/
光盘 A 2 z%]3`_I
手机 B 3 _}j6Pw'
手机 C 3 g*-}9~
23、说明:初始化表table1 L'$({
TRUNCATE TABLE table1 Zbr1e5?
24、说明:选择从10到15的记录 g7w#;E
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc o4^#W;%w
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三、技巧 VVEJE$
1、1=1,1=2的使用,在SQL语句组合时用的较多 \'X-><1
"where 1=1" 是表示选择全部 "where 1=2"全部不选, M<x><U#]A
如: ?y@;=x!'
if @strWhere !='' *&5./WEOH
begin uG+eF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1wE`kbC<
end [B^V{nUBc
else 7CCSG{k
begin a
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @7t*X-P.;-
end 4<- E0
我们可以直接写成 [fJxbr"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +jN)$Y3Ya
2、收缩数据库 Bnz}:te}
--重建索引 gF]IAZCi
DBCC REINDEX ?IDkDv!na~
DBCC INDEXDEFRAG DG=_E\"#
--收缩数据和日志 ; m:I
DBCC SHRINKDB PWV+M@
DBCC SHRINKFILE !95Q4WH-@
3、压缩数据库 OTEx9
dbcc shrinkdatabase(dbname) j'XND`3
4、转移数据库给新用户以已存在用户权限 w[uwhd
exec sp_change_users_login 'update_one','newname','oldname' uZP(-}
go lrgvY>E0
5、检查备份集 /GA-1cS_(
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 5r0Sl89J
6、修复数据库 !MOcF5M
ALTER DATABASE [dvbbs] SET SINGLE_USER Q@s G6iz
GO {\VmNnw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /AIFgsaY
GO ;
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ALTER DATABASE [dvbbs] SET MULTI_USER yn2k!2]&T<
GO m~@Lt~LZs
7、日志清除 G&yF9s)Lvs
SET NOCOUNT ON ^J@
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DECLARE @LogicalFileName sysname, >qdRqy)DC
@MaxMinutes INT, +p-S36K~,7
@NewSize INT yg%T{hyzH
USE tablename -- 要操作的数据库名 (OG>=h8?
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 CelM~W$=u
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 5(DnE?}vo
@NewSize = 1 -- 你想设定的日志文件的大小(M) O_D;_v6Ii+
-- Setup / initialize _z3^.QP
DECLARE @OriginalSize int [5]*
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SELECT @OriginalSize = size Ct0%3]<J
FROM sysfiles ]2z
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WHERE name = @LogicalFileName NV^n}]ci
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?o d*"M
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1!R:}r3t
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' QjsN7h&%
FROM sysfiles %G jjl*`E
WHERE name = @LogicalFileName ks8x xY
CREATE TABLE DummyTrans F '55BY*!
(DummyColumn char (8000) not null) ([ hd
DECLARE @Counter INT, |H8UT SX+
@StartTime DATETIME, r+nhm"9
@TruncLog VARCHAR(255) =V^8RlBi
SELECT @StartTime = GETDATE(), 0[s<!k9=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' D|8h^*Ya
DBCC SHRINKFILE (@LogicalFileName, @NewSize) z.:IUm{z
EXEC (@TruncLog) U}W7[f lc
-- Wrap the log if necessary. C2?p>S/q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *L5L.: Ze
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) z"!=A}i
AND (@OriginalSize * 8 /1024) > @NewSize B 3eNvUFZg
BEGIN -- Outer loop. s`L>mRw`
SELECT @Counter = 0 c`V~?]I>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M'xG.'
BEGIN -- update 3UGdXufw
INSERT DummyTrans VALUES ('Fill Log') p|=0EWo4U
DELETE DummyTrans o&HFlDZ5jO
SELECT @Counter = @Counter + 1 {"^#CSi
END =!2(7Nr
EXEC (@TruncLog) q%FXox~b
END 7=4V1FS6i
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ld'Aaxl&
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + h{Y#. j~aS
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' I\VC2U
FROM sysfiles T( bFn?
WHERE name = @LogicalFileName I=V]_Ik4N
DROP TABLE DummyTrans RTYhgq
SET NOCOUNT OFF x;/%`gKn8
8、说明:更改某个表 r)Iq47Uiw
exec sp_changeobjectowner 'tablename','dbo' ?E7.x%n7X5
9、存储更改全部表 [M:BJ%*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch D^2yP~(
@OldOwner as NVARCHAR(128), :;Wh!8+j
@NewOwner as NVARCHAR(128) G6j9,#2@
AS $!"*h
DECLARE @Name as NVARCHAR(128) v:Z.8m8D
DECLARE @Owner as NVARCHAR(128) ^ `Y1
DECLARE @OwnerName as NVARCHAR(128) 9 Dx9alJR
DECLARE curObject CURSOR FOR }!Xj{Eoc
select 'Name' = name, xW'(]Z7_
'Owner' = user_name(uid) -cWxS{vO
from sysobjects n]%yf9,w
where user_name(uid)=@OldOwner E9S&UU,K
order by name [3hOc/]s
OPEN curObject h+Tt+Q\
FETCH NEXT FROM curObject INTO @Name, @Owner f<( ysl1[
WHILE(@@FETCH_STATUS=0) 4+r26S,T
BEGIN J+8T Ie
if @Owner=@OldOwner GwZ(3
begin btU:=6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @c{b\is2
exec sp_changeobjectowner @OwnerName, @NewOwner )V*V
end U*Pi%J
-- select @name,@NewOwner,@OldOwner r1X\$&
FETCH NEXT FROM curObject INTO @Name, @Owner m_1BB$lyP2
END 38O_PK
close curObject (:T\<
deallocate curObject W RVm^
GO (cqVCys
10、SQL SERVER中直接循环写入数据 "4qv
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declare @i int 6}e"$Ee}9
set @i=1 m-!Uy$yM
while @i<30 )3~):+
begin [?Q$b5j/M
insert into test (userid) values(@i) +0WI;M4i
set @i=@i+1 s:#\U!>0`
end giz#(61j^
小记存储过程中经常用到的本周,本月,本年函数 OO+QH 2j
Dateadd(wk,datediff(wk,0,getdate()),-1) )}jXC4
Dateadd(wk,datediff(wk,0,getdate()),6) G2}e@L0
Dateadd(mm,datediff(mm,0,getdate()),0) +eD+Z.{
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =`6_{<&
Dateadd(yy,datediff(yy,0,getdate()),0) {QTnVS't 0
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4&([<gyR<
上面的SQL代码只是一个时间段 !5K9L(gqb
Dateadd(wk,datediff(wk,0,getdate()),-1) 9;u&,R
Dateadd(wk,datediff(wk,0,getdate()),6) }e* OprF
就是表示本周时间段. X,h"%S<c#H
下面的SQL的条件部分,就是查询时间段在本周范围内的: K PSHBv-#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,L}
而在存储过程中 pe$l'ur
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) |\MgE.N
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) mdTCe
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