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。 ES[]A&tf
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一、基础 tU>4?`)E
1、说明:创建数据库
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CREATE DATABASE database-name N gOc2I
2、说明:删除数据库 ='HLA-uT
drop database dbname Qy) -gax:,
3、说明:备份sql server :tLMh08h
--- 创建 备份数据的 device 7:OF>**
USE master }9L;|ul6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2%j"E{J&
--- 开始 备份 h ?+vH{}j
BACKUP DATABASE pubs TO testBack BNbz{tbX"
4、说明:创建新表 !]#;'
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) E1|:t$>Ld
根据已有的表创建新表: r5uX?^mJ0
A:create table tab_new like tab_old (使用旧表创建新表) Q_|Lv&
B:create table tab_new as select col1,col2... from tab_old definition only .vpx@_;]9
5、说明:删除新表 .WW|v
drop table tabname iMp_1EXe
6、说明:增加一个列 !A"-9OS2
Alter table tabname add column col type ^L's45&_
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 tnw6[U!rh=
7、说明:添加主键: Alter table tabname add primary key(col) CSMx]jbb
说明:删除主键: Alter table tabname drop primary key(col) [3(lk_t
8、说明:创建索引:create [unique] index idxname on tabname(col....) f`p"uLNo<
删除索引:drop index idxname '6Yx03t
注:索引是不可更改的,想更改必须删除重新建。 iKgH
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9、说明:创建视图:create view viewname as select statement E^V4O l<
删除视图:drop view viewname NKRH>2,
10、说明:几个简单的基本的sql语句 f >\~h,SLL
选择:select * from table1 where 范围 ~"WN4
插入:insert into table1(field1,field2) values(value1,value2) Gv6#LcF#
删除:delete from table1 where 范围 k)S'@>n{u
更新:update table1 set field1=value1 where 范围 }zHG]k,j
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! x]|-2t
排序:select * from table1 order by field1,field2 [desc] Ba;tEF{X
总数:select count as totalcount from table1 2r#W#z%vS
求和:select sum(field1) as sumvalue from table1 Yfx'7gj
平均:select avg(field1) as avgvalue from table1 ~
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最大:select max(field1) as maxvalue from table1 ?) VBkA5j
最小:select min(field1) as minvalue from table1 l~GcD
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11、说明:几个高级查询运算词 p}-B>v
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A: UNION 运算符 {8J+Y}
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,+E"s3NW
B: EXCEPT 运算符 zT jk^
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 o$,e#q)8
C: INTERSECT 运算符 b$eZ>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。 rFYw6&;vOi
注:使用运算词的几个查询结果行必须是一致的。 R"[U<^
12、说明:使用外连接 t
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A、left outer join: wRj&k(?*
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。 -{S:sK.o
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 Y kcN-
B:right outer join: O.OSLezTQ
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。 &e1(| qax
C:full outer join: Z=>#|pW,)
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。 [xg&`x9,.
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二、提升 4'0rgS
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) EnXTL]=0S
法一:select * into b from a where 1<>1 3 3b 3v\N
法二:select top 0 * into b from a BW&)Zz
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _.3O(? p,
insert into b(a, b, c) select d,e,f from b; #Ue_
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) ]jwF[D
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 UU]a).rz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. w:o,mzuXK
4、说明:子查询(表名1:a 表名2:b) vrvOPLiQ
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) _0qp!-l}
5、说明:显示文章、提交人和最后回复时间 DsF<P@O6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ffS]%qa
6、说明:外连接查询(表名1:a 表名2:b) Y'2 |GJc2
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Fs;_z9ej-u
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; / FA0(< -}
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 KJN{p~Q
select * from table1 where time between time1 and time2 e'1}5Ky
select a,b,c, from table1 where a not between 数值1 and 数值2 `'M}.q,k~
9、说明:in 的使用方法 wx)Yl1C
select * from table1 where a [not] in ('值1','值2','值4','值6') 8zk?:?8%{
10、说明:两张关联表,删除主表中已经在副表中没有的信息 zsha/:b
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 44(l1xEN+
11、说明:四表联查问题: *9xv0hRQ%?
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 ..... j_HwR9^fd,
12、说明:日程安排提前五分钟提醒 W\J wEb9Y
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 /|2 hW`G
13、说明:一条sql 语句搞定数据库分页 YCEdt>5PA
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 <GRrw
14、说明:前10条记录 rP7f~"L
select top 10 * form table1 where 范围 h[I~D`q)v
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.) *S=zJyAO
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) O#S27.
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 gN/6%,H}
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2';f8JLY
17、说明:随机取出10条数据 .@(9v.:_u
select top 10 * from tablename order by newid() W=@]YI
18、说明:随机选择记录 !_My]>S
select newid() 8\@&~&(y:
19、说明:删除重复记录 !L_\6;aP,x
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %(y0,?*
20、说明:列出数据库里所有的表名 q\a'pp9d
select name from sysobjects where type='U' _qQB.Dzo:
21、说明:列出表里的所有的 *T{P^q.s~[
select name from syscolumns where id=object_id('TableName') .YcI .
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。 x*2' I
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 !/Wp0E'A
显示结果: 6Cd% @Q2cr
type vender pcs %>Y86>mVz
电脑 A 1 ]S#m
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电脑 A 1 beCTOmC
光盘 B 2 ~]&,v|g&
光盘 A 2 rkz_h
手机 B 3 V[T`I a\
手机 C 3 UN6Du\)]d
23、说明:初始化表table1 ]Uee!-dZ
TRUNCATE TABLE table1 NRgNW1#
24、说明:选择从10到15的记录 pv #uLo
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }tRY,f
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三、技巧 1rmK#ld"=Z
1、1=1,1=2的使用,在SQL语句组合时用的较多 vkQkU,q
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !R.*Vn[
如: V"{+cPBO)
if @strWhere !='' {@8TGHKv
begin '8b/TL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere wa*/Am9;~
end 5??\[C^"}
else l3C%`[MB
begin "=97:H{!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Mk~]0d
end "]M]pR/j
我们可以直接写成 io{uN/!X_J
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Vx6/Rehj
2、收缩数据库 B5Y
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--重建索引 {2Jn#&Z29
DBCC REINDEX x{';0MkUV
DBCC INDEXDEFRAG -1 Ok_h"
--收缩数据和日志 8Vb.%f&I
DBCC SHRINKDB 1JI\e6]I
DBCC SHRINKFILE vhQ IkB8
3、压缩数据库 Rg!Fu
dbcc shrinkdatabase(dbname) 39(]UO6^;
4、转移数据库给新用户以已存在用户权限 "\9!9U#!
exec sp_change_users_login 'update_one','newname','oldname' F qW[L>M'
go vS{zLXg
5、检查备份集 05cyWg9a
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' - s,M+Q(<
6、修复数据库 L| uoFG{
ALTER DATABASE [dvbbs] SET SINGLE_USER =6sL}$
GO Pgg\(D#X`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |/R)FT#i
GO W%xg;uzp
ALTER DATABASE [dvbbs] SET MULTI_USER MWxv\o
GO N5%zbfKM
7、日志清除 9j;L-
SET NOCOUNT ON ~;*SW[4
DECLARE @LogicalFileName sysname, SXW8p>1Jw
@MaxMinutes INT, ,c;u]
@NewSize INT :DlgNR`bq
USE tablename -- 要操作的数据库名 t<|S7EqIL
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 N=QeeAI}}m
@MaxMinutes = 10, -- Limit on time allowed to wrap log. l12_&o"C~
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9$u'2TV
-- Setup / initialize P~5[.6gW
DECLARE @OriginalSize int )Uv lEG']
SELECT @OriginalSize = size @1w9!\7Vt
FROM sysfiles e)WpqaI
WHERE name = @LogicalFileName !6UtwCVR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + o`8dqP
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :bhpYEUMx
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^K#PcPF-j
FROM sysfiles t'@qb~sf
WHERE name = @LogicalFileName !u0qF!/W
CREATE TABLE DummyTrans VQQtxHTC3
(DummyColumn char (8000) not null) $]Vvu{
DECLARE @Counter INT, dBKceL v
@StartTime DATETIME, EN =oA P
@TruncLog VARCHAR(255) mrzrQ@sN
SELECT @StartTime = GETDATE(), g0P^O@8
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;;9W/m~]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o6PDCaT7
EXEC (@TruncLog) Tjfg[Z/x
-- Wrap the log if necessary. 8d90B9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired &{Zt(%\ '
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) fg mIx
AND (@OriginalSize * 8 /1024) > @NewSize d&dp#)._8
BEGIN -- Outer loop.
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SELECT @Counter = 0 }T}9AQ}|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) <9]9;
BEGIN -- update 8KQ]3Z9p
INSERT DummyTrans VALUES ('Fill Log') us2X:X)
DELETE DummyTrans 'n9<z)/,!
SELECT @Counter = @Counter + 1 a19yw]hF5
END Y 7a<3>
EXEC (@TruncLog) SOq{`~,4B
END I?l%RdGW
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Jv|uI1V
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + F3aOKV^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' a5v}w7vL
FROM sysfiles TfD]`v`]
WHERE name = @LogicalFileName aP%2CP~_ P
DROP TABLE DummyTrans rHir>
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SET NOCOUNT OFF iG\]
8、说明:更改某个表 dA`.
exec sp_changeobjectowner 'tablename','dbo' ]pZxbs&Vb
9、存储更改全部表 ^=H. .pr
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch f
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@OldOwner as NVARCHAR(128), 0'giAA
@NewOwner as NVARCHAR(128) FZW)C'j
AS FJ|6R( T_
DECLARE @Name as NVARCHAR(128) dU7+rc2,CU
DECLARE @Owner as NVARCHAR(128) (QPfrR=J4
DECLARE @OwnerName as NVARCHAR(128) TsPx"+>7`
DECLARE curObject CURSOR FOR y&HfF~
select 'Name' = name, fgs){Ng`
'Owner' = user_name(uid) .#M'
from sysobjects yA8e"$
where user_name(uid)=@OldOwner rNgFsFQ>.
order by name s<i& q {r
OPEN curObject BM(8+Wj
FETCH NEXT FROM curObject INTO @Name, @Owner "Dc6kn^}3
WHILE(@@FETCH_STATUS=0) $c!cO" U
BEGIN d+1q[,-
if @Owner=@OldOwner 9aED6
begin TTS.wBpR,
set @OwnerName = @OldOwner + '.' + rtrim(@Name) %>dCAj"
exec sp_changeobjectowner @OwnerName, @NewOwner }/ p>DMN
end 9t.u9C=!F
-- select @name,@NewOwner,@OldOwner QJL%J
FETCH NEXT FROM curObject INTO @Name, @Owner DS@ZE Q`F
END !$/1Q+
close curObject :N \j@yJK
deallocate curObject U#I8Rd I,
GO /B$9B
10、SQL SERVER中直接循环写入数据 `aj;FrF
declare @i int 2VrO8q(
set @i=1 J33enQd
while @i<30 Xndgs}zz
begin mVg$z
insert into test (userid) values(@i) _I$\O5
set @i=@i+1 ^
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end (vq0Gl
小记存储过程中经常用到的本周,本月,本年函数 tgy= .o]
Dateadd(wk,datediff(wk,0,getdate()),-1) 8X6F6RK6,1
Dateadd(wk,datediff(wk,0,getdate()),6) wUGSM"~
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Dateadd(mm,datediff(mm,0,getdate()),0) mgIB8D+6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7QXA*.'
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Dateadd(yy,datediff(yy,0,getdate()),0) F~;G[6}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -6URM`y'j
上面的SQL代码只是一个时间段 2S~cW./#fX
Dateadd(wk,datediff(wk,0,getdate()),-1) K3uNR w
Dateadd(wk,datediff(wk,0,getdate()),6) #kO.'oIl
就是表示本周时间段. {*gO1TZt9
下面的SQL的条件部分,就是查询时间段在本周范围内的: N$8do?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 3ErW3Ac Ou
而在存储过程中 I<v1S
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [Yo3=(7J
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) j.? '*?P