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。 _rs#h)
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一、基础 =[1W.Zt
1、说明:创建数据库 SI;G|uO;/
CREATE DATABASE database-name uT-WQ/id
2、说明:删除数据库 }a<MVG:>SF
drop database dbname ,nHz~Xi1t
3、说明:备份sql server DN^ln%#
--- 创建 备份数据的 device 5V?1/
USE master /%xK-z,V
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;"Ot\:0
--- 开始 备份 zv0RrF^
BACKUP DATABASE pubs TO testBack H?'VQ=j
4、说明:创建新表 N_gjOE`x5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;V@}
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根据已有的表创建新表: `gss(o1}
A:create table tab_new like tab_old (使用旧表创建新表) { @-Q1
B:create table tab_new as select col1,col2... from tab_old definition only :A[bqRqe
5、说明:删除新表 ww\/$ |
drop table tabname "{V,(w8Dt
6、说明:增加一个列 [dzb{M6_
Alter table tabname add column col type jNIM1_JjD
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。 ![vc/wuf
7、说明:添加主键: Alter table tabname add primary key(col) Tu6he8Q-
说明:删除主键: Alter table tabname drop primary key(col) b-O4IDIT
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?` `+OH
删除索引:drop index idxname OOk53~2id
注:索引是不可更改的,想更改必须删除重新建。 1:>RQPXcWv
9、说明:创建视图:create view viewname as select statement Q'|cOQX
删除视图:drop view viewname G*"N}M1)
10、说明:几个简单的基本的sql语句 |f>y"T+1
选择:select * from table1 where 范围 9*2hBNp+
插入:insert into table1(field1,field2) values(value1,value2) !Uj !Oy
删除:delete from table1 where 范围 ^mz_T+UOe
更新:update table1 set field1=value1 where 范围 gj'ar
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %^5$=w
排序:select * from table1 order by field1,field2 [desc] n]o+KT\
总数:select count as totalcount from table1 P'
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求和:select sum(field1) as sumvalue from table1 lN1zfM
平均:select avg(field1) as avgvalue from table1 A?7%q^;E
最大:select max(field1) as maxvalue from table1 C#r`oZS1
最小:select min(field1) as minvalue from table1 5#fLGXP
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11、说明:几个高级查询运算词 rmhCuY?f
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A: UNION 运算符 *U8#'Uan
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。 +f7?L]wzic
B: EXCEPT 运算符 ivagS\Q
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。 zm~~mz A
C: INTERSECT 运算符 .i. |wY
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。 vj_oMmjKw
注:使用运算词的几个查询结果行必须是一致的。 E""/dC:B
12、说明:使用外连接 ?"C]h s
A、left outer join: 2;&13%@!
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 oqY?#p/
B:right outer join: vc!S{4bN
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。 H?~u%b@
C:full outer join: O.4"h4{'
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。 B{K'"uC
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二、提升 ^Qr
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) cPN7^*
法一:select * into b from a where 1<>1 EjF}yuq[
法二:select top 0 * into b from a CVUJ(D&Q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 1uH\Bn]p?
insert into b(a, b, c) select d,e,f from b; SP*5 W)6
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) ,AD| u_pP
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M\<!m^~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. u+R?N%
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4、说明:子查询(表名1:a 表名2:b) B`WfJ2*2
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) =L=#PJAPj
5、说明:显示文章、提交人和最后回复时间 7L\GI`y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b m3XH3FgKz
6、说明:外连接查询(表名1:a 表名2:b) (Q4_3<G+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c y-@!, @e
7、说明:在线视图查询(表名1:a ) g 764wl
select * from (SELECT a,b,c FROM a) T where t.a > 1; WR-C_1-pT
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 I{AU,
select * from table1 where time between time1 and time2 "TV.$s$.
select a,b,c, from table1 where a not between 数值1 and 数值2 $XI<s$P%(%
9、说明:in 的使用方法 ,mX|TI<*
select * from table1 where a [not] in ('值1','值2','值4','值6') Q* 4q3B&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 czb%%:EJs|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) zo5.}mr+
11、说明:四表联查问题: %%Kg'{-:
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 ..... Ly<;x^D
12、说明:日程安排提前五分钟提醒 YH[_0!JY^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 EGDE4n5>I
13、说明:一条sql 语句搞定数据库分页 5]Ra?rF
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 6P~"7k
14、说明:前10条记录 }ri*e2y)
select top 10 * form table1 where 范围 2at?9{b
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)VES
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) g@y"
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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 $`Xx5Ts7
(select a from tableA ) except (select a from tableB) except (select a from tableC) '-S&i{H
17、说明:随机取出10条数据 _l,Z38
select top 10 * from tablename order by newid() P3yiJ|vP
18、说明:随机选择记录 StDmJ]
select newid() 1;xw)65
19、说明:删除重复记录 =5/;h+bk+3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 9e)+<H
20、说明:列出数据库里所有的表名 d-<y'GYw
select name from sysobjects where type='U' h.9Lh ;j
21、说明:列出表里的所有的 (XwLKkw0n
select name from syscolumns where id=object_id('TableName') uy9B8&Sr
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 pjCWg4ya
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type )e2IT*7
显示结果: `p{!5
type vender pcs h]MVFn{
电脑 A 1 -5cH$]1\
电脑 A 1 }H#t( 9,U
光盘 B 2 #rpqt{ml
光盘 A 2 :I'Ezxv|
手机 B 3 -Wn.@bz6B
手机 C 3 xI4I1"/
23、说明:初始化表table1 u/[]g+
TRUNCATE TABLE table1 Yq?I>
24、说明:选择从10到15的记录 i-FUAR
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc HV9SdJOf
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三、技巧 :|M/+XPu
1、1=1,1=2的使用,在SQL语句组合时用的较多 <ut DZ#k
"where 1=1" 是表示选择全部 "where 1=2"全部不选, huoKr
如: mo,l`UL
if @strWhere !='' pG( knu
begin y9L#@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ye|a#a9N
end oyt//SE
else 05KoxFO?
begin $
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "k<:a2R
end M&ij[%i
我们可以直接写成 ]jb4Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7ILa H|eN
2、收缩数据库 |{PJT#W%
--重建索引 J4}\V$ysN
DBCC REINDEX <s>/< kW:
DBCC INDEXDEFRAG
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--收缩数据和日志 LZ)m](+M
DBCC SHRINKDB !"J#,e|
DBCC SHRINKFILE uK:-g,;
3、压缩数据库 dT)KvqX
dbcc shrinkdatabase(dbname) eM+;x\jo?
4、转移数据库给新用户以已存在用户权限 8>{W:?I
exec sp_change_users_login 'update_one','newname','oldname' !NYM(6!(
go gc@#O#K~h^
5、检查备份集 ?GNF=#=M
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "x;k'{S
6、修复数据库 n+qVT4o
ALTER DATABASE [dvbbs] SET SINGLE_USER &fSc{/
GO E)O|16f|>
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK tt]V$V
GO 0['"m^l0S
ALTER DATABASE [dvbbs] SET MULTI_USER = (gmd>N
GO eAsX?iaH
7、日志清除 R-Q1YHUQM
SET NOCOUNT ON bfJ`}xl(8
DECLARE @LogicalFileName sysname, 6rQpK&Jx
@MaxMinutes INT, egvy#2b@
@NewSize INT &@HNz6KO
USE tablename -- 要操作的数据库名 ix9HSa{d
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +%Yc4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. mp,e9Nd;
@NewSize = 1 -- 你想设定的日志文件的大小(M) N+M&d3H`
-- Setup / initialize f4k5R
DECLARE @OriginalSize int ;(Xe@OtW
SELECT @OriginalSize = size `MsYgd
FROM sysfiles >I&
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WHERE name = @LogicalFileName @qPyrgy
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' W/r mm*
FROM sysfiles {?/8jCVd
WHERE name = @LogicalFileName T5azYdzJy
CREATE TABLE DummyTrans V`\f+Uu
(DummyColumn char (8000) not null)
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DECLARE @Counter INT, E ;!<Z4
@StartTime DATETIME, *?bk?*?s
@TruncLog VARCHAR(255) AM[jL'r|
SELECT @StartTime = GETDATE(), % R|"Afa=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Q*:h/Lhb&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) vV.~76AD5
EXEC (@TruncLog) 6%kJDY.
-- Wrap the log if necessary. bqrJP3
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired qggk:cN1
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (~Uel1~@
AND (@OriginalSize * 8 /1024) > @NewSize }@14E-N=
BEGIN -- Outer loop. (.,'}+1
SELECT @Counter = 0 P-+M,>vNy[
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ZS XRzH~0
BEGIN -- update lU$4NUwM
INSERT DummyTrans VALUES ('Fill Log') FKox0Jmh=
DELETE DummyTrans g. ?*F#2
SELECT @Counter = @Counter + 1 TH>?Gi)"
END +`*qlP;
EXEC (@TruncLog) 7wQ+giu
END `pi-zE)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )[^y
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + \-
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "%E-X:Il#
FROM sysfiles y|6@-:B.
WHERE name = @LogicalFileName {OO*iZ.O
DROP TABLE DummyTrans ov`^o25f
SET NOCOUNT OFF ?+n&hHRg
8、说明:更改某个表 JOrELrMx
exec sp_changeobjectowner 'tablename','dbo' 5@czK*5
9、存储更改全部表 N^\2
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @VC .>
@OldOwner as NVARCHAR(128), LZr0]g{Pu/
@NewOwner as NVARCHAR(128) FgWkcV6B
AS dK}WM46$
DECLARE @Name as NVARCHAR(128) #0bO)m+NZ
DECLARE @Owner as NVARCHAR(128) oWp}O?
DECLARE @OwnerName as NVARCHAR(128) ZU|6jI}
DECLARE curObject CURSOR FOR dP$8JI{
select 'Name' = name, _ }E-~I>
'Owner' = user_name(uid) %j'G.*TD
from sysobjects mDQEXMD
where user_name(uid)=@OldOwner rGnI( m.
order by name |rHG%VnBH
OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner 1Xy8|OFc[
WHILE(@@FETCH_STATUS=0) M3Khc#5S(
BEGIN a)!![X?\
if @Owner=@OldOwner 9-
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begin mRhd/|g*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Zc'|!pT _
exec sp_changeobjectowner @OwnerName, @NewOwner /m`}f]u
end YDQ:eebg(
-- select @name,@NewOwner,@OldOwner gA~20LSt
FETCH NEXT FROM curObject INTO @Name, @Owner K(nS$x1G
END M{?zvq?d
close curObject DX}B0B
deallocate curObject TGU:(J'^
GO 4\LZD{
10、SQL SERVER中直接循环写入数据 rv9B}%e
declare @i int `$s)X$W?
set @i=1 kSbO[)p
while @i<30 ;,1=zhKU.
begin lPM3}52Xu
insert into test (userid) values(@i) pOC% oj
set @i=@i+1 f64(a\Rw!^
end Fe!D%p Qv
小记存储过程中经常用到的本周,本月,本年函数 ^WE4*.(
Dateadd(wk,datediff(wk,0,getdate()),-1) +|y*}bG
Dateadd(wk,datediff(wk,0,getdate()),6) F9(._ow[
Dateadd(mm,datediff(mm,0,getdate()),0) GX4QaT%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) _om0
e=5)
Dateadd(yy,datediff(yy,0,getdate()),0) O:
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) }]AT _bh,
上面的SQL代码只是一个时间段 @j O4EEe:
Dateadd(wk,datediff(wk,0,getdate()),-1) q7X}MAW
Dateadd(wk,datediff(wk,0,getdate()),6) r&}(9Cq&"y
就是表示本周时间段. {5^K Xj$B
下面的SQL的条件部分,就是查询时间段在本周范围内的: \6{krn|
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) lVPOYl%
而在存储过程中 9G0D3F
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *GQDfs`m
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) pzp,t(%j