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。 '3Lx!pMhN
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一、基础 v J,xz*rc`
1、说明:创建数据库 J&]
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CREATE DATABASE database-name ['9OGV\
2、说明:删除数据库 iz,q8}/(
drop database dbname c_DB^M!h
3、说明:备份sql server K{[Fa,]'
--- 创建 备份数据的 device >Y*iy
USE master !O%f)v?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ,XF6Xsg2
--- 开始 备份 cbg3bi
BACKUP DATABASE pubs TO testBack lw/
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4、说明:创建新表 4*ty&s=5OJ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 'amex
根据已有的表创建新表: bj*v'
A:create table tab_new like tab_old (使用旧表创建新表) @Ig,_i\UY:
B:create table tab_new as select col1,col2... from tab_old definition only &55uT;7] a
5、说明:删除新表 XTn{1[.O
drop table tabname ogh2kht
6、说明:增加一个列 BYA=M*f
Alter table tabname add column col type ;R-
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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。 A~~|X
7、说明:添加主键: Alter table tabname add primary key(col) brhJ&|QDE
说明:删除主键: Alter table tabname drop primary key(col) HWao3 Lz
8、说明:创建索引:create [unique] index idxname on tabname(col....) 5kL# V
删除索引:drop index idxname `A}{
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注:索引是不可更改的,想更改必须删除重新建。 eJwii
9、说明:创建视图:create view viewname as select statement :XZJx gx
删除视图:drop view viewname KG./<"c
10、说明:几个简单的基本的sql语句 ?eg@
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选择:select * from table1 where 范围 (}7o
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插入:insert into table1(field1,field2) values(value1,value2) \FaB!7*~
删除:delete from table1 where 范围 4j=@}!TBt
更新:update table1 set field1=value1 where 范围 #@OKp,LJ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |H|eH~.yg&
排序:select * from table1 order by field1,field2 [desc] V'|g
总数:select count as totalcount from table1 V[2<ha[n>
求和:select sum(field1) as sumvalue from table1 14)kKWG
平均:select avg(field1) as avgvalue from table1 U:\oGa84A
最大:select max(field1) as maxvalue from table1 -<VF6k<
最小:select min(field1) as minvalue from table1 ^/RM;`h0
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11、说明:几个高级查询运算词 IEKX'+t'
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A: UNION 运算符 >!ZyykAs
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。 0a;FX0S&
B: EXCEPT 运算符 Jut'xA2Dr
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。 0z2R`=)
C: INTERSECT 运算符 E4fvYV_ra
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。 vXWESy
注:使用运算词的几个查询结果行必须是一致的。 Dqo:X`<bT
12、说明:使用外连接 qi5>GX^t]b
A、left outer join: S
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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。 ^O\1v
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 w}KcLaI
B:right outer join: z%-"'Y]
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。 1PjX:]:
C:full outer join: XS~w_J#q
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。 9$w)_RX9W
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二、提升 &T4Cn@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Y~\xWYR
法一:select * into b from a where 1<>1 kc/H
法二:select top 0 * into b from a LAjw!QB
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) mjJlXA
insert into b(a, b, c) select d,e,f from b; SEn8t"n
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) <PA$hTYM
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ^L2Zo'y [
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ="PywZ
4、说明:子查询(表名1:a 表名2:b) Lm2cW$s
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 3n"&$q6
5、说明:显示文章、提交人和最后回复时间 j1C0LP8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b g&20F`.N*>
6、说明:外连接查询(表名1:a 表名2:b) vf'jz`Z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c UgBY
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7、说明:在线视图查询(表名1:a ) ,}xC) >
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5Szo5
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 HrcnyQ`Q0
select * from table1 where time between time1 and time2 l~>rpG
select a,b,c, from table1 where a not between 数值1 and 数值2 gA8u E
9、说明:in 的使用方法 *h8XbBZH
select * from table1 where a [not] in ('值1','值2','值4','值6') P6Ol+SI#m
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Y- 9j2.{
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pF{Ri
11、说明:四表联查问题: Z|7I }i
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 ..... f#JF5>o
12、说明:日程安排提前五分钟提醒 !{- 3:N7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 x-P_}}K 79
13、说明:一条sql 语句搞定数据库分页 ~1z8G>R
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 NxRiEe#m
14、说明:前10条记录 1JY90l$ME
select top 10 * form table1 where 范围 t5[JN:an
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) J-,X0v"
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J!qEj{
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 @o.i2iG
(select a from tableA ) except (select a from tableB) except (select a from tableC) Z-=7QK.\{
17、说明:随机取出10条数据 &]A1 _dy
select top 10 * from tablename order by newid() %x)U8
18、说明:随机选择记录 +mel0ZStS
select newid() R}YryzV5
19、说明:删除重复记录 m=b+V#4i(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 8IcQpn#
20、说明:列出数据库里所有的表名 e5y`CXX
select name from sysobjects where type='U' 1;sAt;/W8
21、说明:列出表里的所有的
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select name from syscolumns where id=object_id('TableName') Hqy>!1!
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 T</gWW
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type cnO4NUDv
显示结果: HCZ%DBU96
type vender pcs iONql7S @
电脑 A 1 y3$\ m
电脑 A 1 ZI*A0_;L
光盘 B 2 `9)2nkJk'z
光盘 A 2
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手机 B 3 eHZl-|-
手机 C 3 ;(Va_
23、说明:初始化表table1 w9}IM149
TRUNCATE TABLE table1 F>nrV
24、说明:选择从10到15的记录 3m9E2R,
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc B}bNl 7
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三、技巧 {:+^[rerj
1、1=1,1=2的使用,在SQL语句组合时用的较多 U/lra&P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Y'":OW#oN
如: DdW8~yI&
if @strWhere !='' 745PCC'FK
begin lY,1 w
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~DS9{Y
end P?-44m#
else e=$xn3)McY
begin *)sz]g|d
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' eesLTyD2_
end yr DYw T
我们可以直接写成 66;O 3g'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere R9HS%O6b6
2、收缩数据库 e/%YruzS
--重建索引 rx)Q]
DBCC REINDEX rkXSygb
DBCC INDEXDEFRAG X0L{#U
--收缩数据和日志 O
DBCC SHRINKDB U5s]dUs (
DBCC SHRINKFILE 'GT`%c k
3、压缩数据库 )^xmy6k
dbcc shrinkdatabase(dbname) 1a4 $.
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4、转移数据库给新用户以已存在用户权限 !0_Y@>2
exec sp_change_users_login 'update_one','newname','oldname' q&x#S_!
go JB}h}nb
5、检查备份集 WWs>@lCK
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LB0=V0|
6、修复数据库 2)]*re)
ALTER DATABASE [dvbbs] SET SINGLE_USER [^P2Kn
GO iIRigW
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4H'&5
GO %^A++Z$`
ALTER DATABASE [dvbbs] SET MULTI_USER qa#F}aGd
GO 1@Gv`{v
7、日志清除 x/v+7Pt_
SET NOCOUNT ON 2?&ptN)`N
DECLARE @LogicalFileName sysname, `84yGXLK
@MaxMinutes INT, x$4'a~E
@NewSize INT XAkl,Y
USE tablename -- 要操作的数据库名 3mpjSL
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _3JTHf<+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. CKx}.<_
@NewSize = 1 -- 你想设定的日志文件的大小(M) 6d6SP)|j
-- Setup / initialize zh#uwT1u
DECLARE @OriginalSize int )]Rr:i9n
SELECT @OriginalSize = size *GnO&&m'B
FROM sysfiles >@W#@W*I@
WHERE name = @LogicalFileName XS@6jbLE
SELECT 'Original Size of ' + db_name() + ' LOG is ' + A}O9e
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + D7wWk
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' e70*y'1fu
FROM sysfiles %oQj^r!Xd
WHERE name = @LogicalFileName KO7cZME
CREATE TABLE DummyTrans H2-(
(DummyColumn char (8000) not null) bBL"F!.
DECLARE @Counter INT, }3e+D
@StartTime DATETIME, \6L=^q=
@TruncLog VARCHAR(255) P40eK0e6
SELECT @StartTime = GETDATE(), S d -+a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *8+YR
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ru
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EXEC (@TruncLog) }Qo8Xps
-- Wrap the log if necessary. b?,y%D)'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired AG%aH=TKp
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /qr8
AND (@OriginalSize * 8 /1024) > @NewSize <taW6=;c
BEGIN -- Outer loop. tc Z~T
SELECT @Counter = 0 ggWfk
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) dDn:^)
BEGIN -- update 4G2V{(@QiZ
INSERT DummyTrans VALUES ('Fill Log') \v_(*
DELETE DummyTrans DO;
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SELECT @Counter = @Counter + 1 W@Wh@eSb;
END XFYl[?`G
EXEC (@TruncLog) irS62Xe
END [0emOS
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 75ob1h"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1:8: yFV
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9IMcp~zX
FROM sysfiles e)8iPu ..
WHERE name = @LogicalFileName bv0 %{u&
DROP TABLE DummyTrans I
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SET NOCOUNT OFF vhW'2<(
8、说明:更改某个表 ?*0kQo'
exec sp_changeobjectowner 'tablename','dbo' 7y3; F7V
9、存储更改全部表 *!kg@ _0K
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch sa($3`d
@OldOwner as NVARCHAR(128), hJM0A3(Cm
@NewOwner as NVARCHAR(128) N4pA3~P
AS a;sZNUSn
DECLARE @Name as NVARCHAR(128) <R$|J|
DECLARE @Owner as NVARCHAR(128) >F
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DECLARE @OwnerName as NVARCHAR(128) AseY.0
DECLARE curObject CURSOR FOR !ywc). ]e
select 'Name' = name, <Lt$qV-#
'Owner' = user_name(uid) "lt[)3*
from sysobjects PE>_;k-@k
where user_name(uid)=@OldOwner 5s9~rm
order by name qZ.\GHS
OPEN curObject 9"e!0Q4 0
FETCH NEXT FROM curObject INTO @Name, @Owner Y|L57F
WHILE(@@FETCH_STATUS=0) zc#`qa:0
BEGIN S/|8'x{<
if @Owner=@OldOwner ]Yy
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begin D3OV.G]`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @\a- =
exec sp_changeobjectowner @OwnerName, @NewOwner X"]ZV]7(]s
end 'n=D$j]X
-- select @name,@NewOwner,@OldOwner }Z|a?J@CZm
FETCH NEXT FROM curObject INTO @Name, @Owner j(rFORT
END 53c6dl
close curObject Fei$94a
deallocate curObject $A,=z
GO U+z&jdnhDR
10、SQL SERVER中直接循环写入数据 Wil+"[Ge
declare @i int >8##~ZuF+
set @i=1 v3B
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while @i<30 h?b{{
begin 9b0Z
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insert into test (userid) values(@i) E4Sp^,
set @i=@i+1 AMr 9rB d
end R B!g,u
小记存储过程中经常用到的本周,本月,本年函数 Gu-Sv!4p
Dateadd(wk,datediff(wk,0,getdate()),-1) !Kis,e
Dateadd(wk,datediff(wk,0,getdate()),6) QB7<$Bp
Dateadd(mm,datediff(mm,0,getdate()),0) {!w]t?h
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) l6~eb=u;9g
Dateadd(yy,datediff(yy,0,getdate()),0) qr*/}F6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) '#fj)
上面的SQL代码只是一个时间段 :MpCj<<[
Dateadd(wk,datediff(wk,0,getdate()),-1) n1ICW 9
Dateadd(wk,datediff(wk,0,getdate()),6) _Cxs"to
就是表示本周时间段. anbr3L[!
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZO,]h9?4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0bor/FU-d
而在存储过程中 -(jcsqDk
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $_y"P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $I'ES#8P6