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。 ;"#y HP`
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一、基础 ? [5>!
1、说明:创建数据库 $!$If(
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CREATE DATABASE database-name o7Z8O,;
2、说明:删除数据库 2yFT` 5+H4
drop database dbname _E8Cvaob
3、说明:备份sql server :.=j)ljTx
--- 创建 备份数据的 device eU`O=uE
USE master ^7i7yM}6(
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h{zb)'R
--- 开始 备份 =_j<x$,b-
BACKUP DATABASE pubs TO testBack Al@. KTK
4、说明:创建新表 3*\Q]|SI!
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SHB'g){P
根据已有的表创建新表: av5a2r0W1
A:create table tab_new like tab_old (使用旧表创建新表) >z/.8!#Q
B:create table tab_new as select col1,col2... from tab_old definition only N^wHO<IO1
5、说明:删除新表 =j~:u.hc'
drop table tabname o%`=+-K
6、说明:增加一个列 'Q7^bF^
Alter table tabname add column col type 8sBT&A6&j
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。 ,uNJz -B8
7、说明:添加主键: Alter table tabname add primary key(col) dIh+h|:
说明:删除主键: Alter table tabname drop primary key(col) g]N'6La
8、说明:创建索引:create [unique] index idxname on tabname(col....) tcRJ1:d
删除索引:drop index idxname a9 q:e
注:索引是不可更改的,想更改必须删除重新建。 Z]tQmV8e
9、说明:创建视图:create view viewname as select statement 79}jK"Gc
删除视图:drop view viewname MwQ4&z#wh
10、说明:几个简单的基本的sql语句 O^6anUV0
选择:select * from table1 where 范围 D@.qdRc3
插入:insert into table1(field1,field2) values(value1,value2) @^ti*`
删除:delete from table1 where 范围 f52P1V]
更新:update table1 set field1=value1 where 范围 fI<d&5&g
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! JKrS;J^97v
排序:select * from table1 order by field1,field2 [desc] ~b
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总数:select count as totalcount from table1 .}Xf<G&
求和:select sum(field1) as sumvalue from table1 yH43Yo#Rk
平均:select avg(field1) as avgvalue from table1 @TXLg2
最大:select max(field1) as maxvalue from table1 Ac*J;fI
最小:select min(field1) as minvalue from table1 \/\w|j
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11、说明:几个高级查询运算词 X6(s][Wn
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x H=15JY1W
A: UNION 运算符 d:^B2~j
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。 H[OgnnM
B: EXCEPT 运算符 IoK/ 2Gp
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。 <-N2<sl
C: INTERSECT 运算符 0b
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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。 GP %hf{
注:使用运算词的几个查询结果行必须是一致的。 |#SZdXg
12、说明:使用外连接 v@M^ukk'}
A、left outer join: /K1cP>oE
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。
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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 `F&~SU,
B:right outer join: *TI?tD
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。 `]@=Hx(
C:full outer join: 6@8z3JW.A
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。 U~"Y8g#qgy
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二、提升 |S|'o*u
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) [Y@>,B!V
法一:select * into b from a where 1<>1 H|wP8uQC
法二:select top 0 * into b from a ]{\M,txo8
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 1(:!6PY
insert into b(a, b, c) select d,e,f from b; <;~u@^>
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) rcMf1\
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 y@LiUe5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. es x/{j;<u
4、说明:子查询(表名1:a 表名2:b) SZ$WC8AX
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) v3XM-+Z4
5、说明:显示文章、提交人和最后回复时间 z,^~H
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )
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6、说明:外连接查询(表名1:a 表名2:b) <Up?w/9
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $7g+/3Fu^
7、说明:在线视图查询(表名1:a ) f38e(Q];m
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6'@ {
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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 x{<l8vL=-c
select * from table1 where time between time1 and time2 E!mv}
select a,b,c, from table1 where a not between 数值1 and 数值2 'x"(OdM:[
9、说明:in 的使用方法 B{:a,V7
select * from table1 where a [not] in ('值1','值2','值4','值6') ~gMt
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10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) gM=:80
11、说明:四表联查问题: m9i/rK_
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 ..... qnj'*]ysBC
12、说明:日程安排提前五分钟提醒 |rZMcl/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 LfFXYX^
13、说明:一条sql 语句搞定数据库分页 $YcB=l
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 w(
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14、说明:前10条记录 SUUN_w~
select top 10 * form table1 where 范围 3z2
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 6(4d3}F
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6Xm'^T
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 T:m"
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(select a from tableA ) except (select a from tableB) except (select a from tableC) CPRVSN0b{4
17、说明:随机取出10条数据 {$yju _[
select top 10 * from tablename order by newid() /"j3B\`?
18、说明:随机选择记录 ;`:YZ+2
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select newid() 7X/t2Vih@
19、说明:删除重复记录 #+AQ:+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Q1?*+]
20、说明:列出数据库里所有的表名 aVc{ aP
select name from sysobjects where type='U' 3+h3?
21、说明:列出表里的所有的 SZHgXl3:
select name from syscolumns where id=object_id('TableName') pWJEFm
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。 (?zD!%
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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 <"P-7/j3j
显示结果: hdrsa}{g
type vender pcs \y=oZk4
电脑 A 1 q^EY?;Y
电脑 A 1 DmLx"%H3
光盘 B 2 zB`woI28
光盘 A 2 ?&~q^t?u
手机 B 3 V8TdtGB.|h
手机 C 3 Tsa]SN14
23、说明:初始化表table1 ]6)u$4X6$
TRUNCATE TABLE table1 x4H#8ZK!
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc x6s|al
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三、技巧 FC,=g`Q!
1、1=1,1=2的使用,在SQL语句组合时用的较多 ZDR@VYi+~
"where 1=1" 是表示选择全部 "where 1=2"全部不选, g;8 wP5i
如: _J W|3q
if @strWhere !='' er)I ".|
begin B<m0YD?>~>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere oYStf5
end BU/A\4xQ,Y
else `;;l {8
begin %g.cE}^
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' uy3<2L#.
end wAprksZL#
我们可以直接写成 &gY) x{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere # Q^".#
2、收缩数据库 }a6t <m`V
--重建索引 VoZ{ I{>|
DBCC REINDEX qVE0[ve
DBCC INDEXDEFRAG ~RuX2u-2&u
--收缩数据和日志 c!4F0(n4
DBCC SHRINKDB #[lhem] IC
DBCC SHRINKFILE G!r)N0?_f
3、压缩数据库 &R_7]f+%)
dbcc shrinkdatabase(dbname) Q]xkDr?
4、转移数据库给新用户以已存在用户权限 \BXzmok
exec sp_change_users_login 'update_one','newname','oldname' +C{-s
go eNAxVF0
5、检查备份集 ?s^3o{!<W
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' TD}<U8I8_
6、修复数据库 'YNdrvz
ALTER DATABASE [dvbbs] SET SINGLE_USER 1" cv5U
GO 1w^wa_qx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK fj5g\m
GO X&qx4DL
ALTER DATABASE [dvbbs] SET MULTI_USER !`Rh2g*o9
GO /;Tc]
7、日志清除 ([u|j
SET NOCOUNT ON XTJD>
DECLARE @LogicalFileName sysname, |0y#} |/
@MaxMinutes INT, U@mznf* J
@NewSize INT RQx8Du<
USE tablename -- 要操作的数据库名 %7)=k}4
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ?W'p&(;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. YNU}R/u6^
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7R2O[=Szq
-- Setup / initialize m,E$KHt (
DECLARE @OriginalSize int zzQWHg]/
SELECT @OriginalSize = size Lqj
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FROM sysfiles U4pIRa)S
WHERE name = @LogicalFileName !SQcV'
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + F`nQS&y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z nc(Q
FROM sysfiles e yJ07
WHERE name = @LogicalFileName GlAI~ \A
CREATE TABLE DummyTrans p?:5U[KM
(DummyColumn char (8000) not null) 5:h[%3'bB
DECLARE @Counter INT, Nujnm$!,Q
@StartTime DATETIME, =#b@7Yw:
@TruncLog VARCHAR(255) -Ks>s
SELECT @StartTime = GETDATE(), w6%
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' m.e]tTe
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )?*YrWO{
EXEC (@TruncLog) I9*cEZ!l=e
-- Wrap the log if necessary. n~* ".ZC'Y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired -1g:3'%
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8-#%l~dr
AND (@OriginalSize * 8 /1024) > @NewSize $RPW/Lyiq
BEGIN -- Outer loop. }~XWtWbd-
SELECT @Counter = 0 'jtC#:ePK
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Wp=3heCa6
BEGIN -- update ~f1g"
INSERT DummyTrans VALUES ('Fill Log') QOF@DvQ
DELETE DummyTrans :o'XE|N
SELECT @Counter = @Counter + 1 bV_nYpo
END pE4a ~:
EXEC (@TruncLog) '-;[8:y.
END e<L@QNX
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 7^q~a(j
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + m|@H`=`d
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9Eyx Ob
FROM sysfiles ~?Q sr
WHERE name = @LogicalFileName 9oWU]A\k>
DROP TABLE DummyTrans !+T1kMP+l
SET NOCOUNT OFF ?['!0PF
8、说明:更改某个表 NI >%v
exec sp_changeobjectowner 'tablename','dbo' @w[i%F,&`
9、存储更改全部表 iq(PC3e`V
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch V2YK T,5
@OldOwner as NVARCHAR(128), >Jz9wo`
@NewOwner as NVARCHAR(128) 'ZfgCu)St
AS Ey46JO"
DECLARE @Name as NVARCHAR(128) c3A\~tHW
DECLARE @Owner as NVARCHAR(128) }htjT/Nm
DECLARE @OwnerName as NVARCHAR(128) dj0; tQ=C
DECLARE curObject CURSOR FOR tMIYVHGy
select 'Name' = name, !>8~R2
'Owner' = user_name(uid) ;;Q^/rkC
from sysobjects )O]T}eI
where user_name(uid)=@OldOwner @;Ttdwg#J
order by name 6o3
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OPEN curObject mPV<a&U
FETCH NEXT FROM curObject INTO @Name, @Owner kSQ8kU_w+
WHILE(@@FETCH_STATUS=0) ':'g!b`/
BEGIN n_8[bkbi
if @Owner=@OldOwner tZrc4$D-
begin /:&!o2&1H
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Lsmcj{1d
exec sp_changeobjectowner @OwnerName, @NewOwner ^PksXfk
end &|>+LP@8
-- select @name,@NewOwner,@OldOwner U2oCSo5:3N
FETCH NEXT FROM curObject INTO @Name, @Owner Ykbg5Z
END u2V-V#jS
close curObject *2'8d8>R%]
deallocate curObject K"}fD;3
GO _]Hna <Ly
10、SQL SERVER中直接循环写入数据 g*|j+<:7
declare @i int %\As
set @i=1 \{,TpK.
while @i<30 W.7rHa
begin {|+Y;V`
insert into test (userid) values(@i) (L_-!=e
set @i=@i+1 !d*[QD8
end S2~cAhR|M
小记存储过程中经常用到的本周,本月,本年函数 Zo9<96I&
Dateadd(wk,datediff(wk,0,getdate()),-1) JE?p'77C
Dateadd(wk,datediff(wk,0,getdate()),6) V|7YRa@
Dateadd(mm,datediff(mm,0,getdate()),0) L+%"ew
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) )
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Dateadd(yy,datediff(yy,0,getdate()),0) #x%'U}sF
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 90}{4&C.^
上面的SQL代码只是一个时间段 QFyL2Xes/
Dateadd(wk,datediff(wk,0,getdate()),-1) mCtS_"W
Dateadd(wk,datediff(wk,0,getdate()),6) G7-BeA8
就是表示本周时间段. I$Nh|eM
下面的SQL的条件部分,就是查询时间段在本周范围内的: o_b[ *
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cPGlT"
而在存储过程中 |m19fg3u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1)
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) B[vj X"yg