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。 s7gf7E#Y
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一、基础 }6(:OB?
1、说明:创建数据库 p`ZGV97
CREATE DATABASE database-name t)ry)[Dxv
2、说明:删除数据库 *gKr1}M
drop database dbname cE#Y,-f
3、说明:备份sql server ucO]&'hu:
--- 创建 备份数据的 device ;<Q_4
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USE master @J)vuGS
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &0blHDMj{#
--- 开始 备份 `fHiY.-
BACKUP DATABASE pubs TO testBack :"^$7
4、说明:创建新表 |8rJqtf +&
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Y`Rf E
根据已有的表创建新表: F:U_gW?
A:create table tab_new like tab_old (使用旧表创建新表) >.A:6
B:create table tab_new as select col1,col2... from tab_old definition only cZ,_O~
5、说明:删除新表 z[Qv}pv
drop table tabname r#}%sof
6、说明:增加一个列 mcracj[B
Alter table tabname add column col type sRG3`>1
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 smNr%}_g
7、说明:添加主键: Alter table tabname add primary key(col) 6C5qW8q]u3
说明:删除主键: Alter table tabname drop primary key(col) w|e i*L
8、说明:创建索引:create [unique] index idxname on tabname(col....) [!$>:_Vq/
删除索引:drop index idxname Tj#XsD?J
注:索引是不可更改的,想更改必须删除重新建。 <;K/Yv'{r
9、说明:创建视图:create view viewname as select statement n*uZ=M_/Q
删除视图:drop view viewname Melc-[
10、说明:几个简单的基本的sql语句 y%AJ>@/;
选择:select * from table1 where 范围 \FM- FQK
插入:insert into table1(field1,field2) values(value1,value2) 1+#8} z:
删除:delete from table1 where 范围 pu#<qD*w
更新:update table1 set field1=value1 where 范围 2HNS|GHb&
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &c!-C_L 2
排序:select * from table1 order by field1,field2 [desc] ]y$C6iUY*
总数:select count as totalcount from table1 -"H9 W:
求和:select sum(field1) as sumvalue from table1 *l}
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平均:select avg(field1) as avgvalue from table1 /+7L`KPD
最大:select max(field1) as maxvalue from table1 Cm>F5$l{
最小:select min(field1) as minvalue from table1 ivk|-C'\
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11、说明:几个高级查询运算词 pq`MO
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A: UNION 运算符
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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。 N"{o3QmA
B: EXCEPT 运算符 ^m9cEl^:nQ
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。 XQPJ(.G
C: INTERSECT 运算符 0]HIc
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。 pQi -
注:使用运算词的几个查询结果行必须是一致的。 ZG|T-r;~
12、说明:使用外连接 wOP}SMn
A、left outer join: l@
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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。 PGDlSB^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 R&A.F+Zgt
B:right outer join: b/`'?|
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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。 3@JwL{C
C:full outer join: 3WHH3co[
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。 w4mL/j
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二、提升 vbU{Et\^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !k^\`jMzw
法一:select * into b from a where 1<>1 'UKB
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法二:select top 0 * into b from a Nt?B(.G
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) FE.:h'^h
insert into b(a, b, c) select d,e,f from b; K9iR>put
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) (A_9;uL^_
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 UF
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Mtlj I6
4、说明:子查询(表名1:a 表名2:b) KAGq\7
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) ;nbvn
5、说明:显示文章、提交人和最后回复时间 L`BLkDm
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6IA~bkc}
6、说明:外连接查询(表名1:a 表名2:b) `B~%TEvMh
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c e BPMT
7、说明:在线视图查询(表名1:a ) "A7tb39*
select * from (SELECT a,b,c FROM a) T where t.a > 1; A'T! og|5
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 hO8B]4=&*
select * from table1 where time between time1 and time2 a,.9eHf
select a,b,c, from table1 where a not between 数值1 and 数值2 y)2]:nD`B
9、说明:in 的使用方法 9j/B3CjW
select * from table1 where a [not] in ('值1','值2','值4','值6') C|+5F,D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 4I$#R
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) EW)]75o{QF
11、说明:四表联查问题: LdcP0G\"VG
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ,fbO}
12、说明:日程安排提前五分钟提醒 /$E1!9J
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 g"xZ{k_3
13、说明:一条sql 语句搞定数据库分页 ev`p!p
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 Y (Q8P{@(
14、说明:前10条记录 d{Z
select top 10 * form table1 where 范围 b.F2m(e2
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.) e2>gQ p/
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) pLRHwL.
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 TA*49Qp
(select a from tableA ) except (select a from tableB) except (select a from tableC) 'sC{d&c
17、说明:随机取出10条数据 q?wBh^
select top 10 * from tablename order by newid() ^(%>U!<<%,
18、说明:随机选择记录 .[7m4iJf
select newid() Kgcg:r:
19、说明:删除重复记录 /dIiFr"e}G
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "qF8'58
20、说明:列出数据库里所有的表名 n']@Spm
select name from sysobjects where type='U' ,+XQ!y%
21、说明:列出表里的所有的 vjW S35i
select name from syscolumns where id=object_id('TableName') 1'h?qv^(
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。 `eA 0Z:`g!
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 ) E5ax~
显示结果: Xa36O5$4]9
type vender pcs gxF3gM
电脑 A 1 'n\ZmG{
电脑 A 1 qzq>C"z\Y$
光盘 B 2 u >x2
光盘 A 2 >%{h_5
手机 B 3 3.soCyxmc
手机 C 3 sf%=q$z
23、说明:初始化表table1 :t(}h!7
TRUNCATE TABLE table1 'O
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24、说明:选择从10到15的记录 rz4S"4
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc :E.mU{
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三、技巧 ,^/;!ErR$
1、1=1,1=2的使用,在SQL语句组合时用的较多 l-5-Tf&j
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |(Sqd;#v
如: 2e+DUZBoC
if @strWhere !='' |
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begin O*CKyW_$t
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere qk+:p]2
end `":< ]lj
else 'kp:yI7w
begin v6]lH9c{,
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' V /|@
end ]F,5Oh :OY
我们可以直接写成 CpA=DnZ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ~s+\Y/@A
2、收缩数据库 #;+GNF}0mG
--重建索引 }V09tK/M
DBCC REINDEX z`{x1*w_
DBCC INDEXDEFRAG yQ\c<z^e
--收缩数据和日志 rN
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DBCC SHRINKDB =5+:<e,&
DBCC SHRINKFILE M}HGFN
3、压缩数据库 8I
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dbcc shrinkdatabase(dbname) N'IzHyo.
4、转移数据库给新用户以已存在用户权限 T<! TmG
exec sp_change_users_login 'update_one','newname','oldname' J-=&B5"O>
go By%aTuV$
5、检查备份集 V_h, UYN
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' yhZ 2-*pTg
6、修复数据库 hD
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ALTER DATABASE [dvbbs] SET SINGLE_USER 6*CvRb&
GO s3oK[:/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !s5 _JO
GO znD0&CS9q
ALTER DATABASE [dvbbs] SET MULTI_USER lBl`R|Gt
GO .7{,u1N'
7、日志清除 k: D<Q
SET NOCOUNT ON po!0j+ r3
DECLARE @LogicalFileName sysname, L\!Pa+Iod
@MaxMinutes INT, *r=6bpi
@NewSize INT <.#i3!
USE tablename -- 要操作的数据库名 fi`*r\
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2wikk]Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. K-sJnQ23'
@NewSize = 1 -- 你想设定的日志文件的大小(M) z;D[7tT
-- Setup / initialize ^C_ ;uz
DECLARE @OriginalSize int *IfLoKS'
SELECT @OriginalSize = size 0jG8Gmh!
FROM sysfiles Z+JPxe#7
WHERE name = @LogicalFileName "RiY#=}sm
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Z
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *}Vg]3$4
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' IOomBy:
FROM sysfiles wm_xH_{F
WHERE name = @LogicalFileName Dhv ^}m@
CREATE TABLE DummyTrans 5V8WSnO
(DummyColumn char (8000) not null) >E6w,Ab
DECLARE @Counter INT, vT)FLhH6*
@StartTime DATETIME, ,x&T8o/a
@TruncLog VARCHAR(255) #,lJ>mTe4
SELECT @StartTime = GETDATE(), [s"xOP9R
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' VI/77
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $zKf>[K
EXEC (@TruncLog) qJj"WU5
-- Wrap the log if necessary. 6;Wns'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired b dP @^Q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =wtu
AND (@OriginalSize * 8 /1024) > @NewSize PF~w$ eeQ
BEGIN -- Outer loop. Bz!SZpW(M
SELECT @Counter = 0 Gg$4O 8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 90X<Qs
BEGIN -- update J4"?D9T3G
INSERT DummyTrans VALUES ('Fill Log') &C6Z-bS"
DELETE DummyTrans R0HzNk
SELECT @Counter = @Counter + 1 )T&ZiHIJ3
END gd#+N]C_
EXEC (@TruncLog) E.45s? r
END `r+zNJ@q
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 4zzJ5,S 1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + gLy1*k4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' }fU"s"
FROM sysfiles Lk#8G>U
WHERE name = @LogicalFileName "V'<dn
DROP TABLE DummyTrans e#BxlC
SET NOCOUNT OFF EIug)S~
8、说明:更改某个表 sYE|
exec sp_changeobjectowner 'tablename','dbo' k nTCX
9、存储更改全部表 %OE
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Z4KYVHD,
@OldOwner as NVARCHAR(128), =^3 Z
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@NewOwner as NVARCHAR(128) OiI29
AS c'O"</
DECLARE @Name as NVARCHAR(128) >{R+j4%
DECLARE @Owner as NVARCHAR(128) \I"n~h^_
DECLARE @OwnerName as NVARCHAR(128) bWv2*XC
DECLARE curObject CURSOR FOR *5m4j=-
select 'Name' = name, 'A2^K5`3
'Owner' = user_name(uid) m?GBvL$
from sysobjects M-7^\wXTA
where user_name(uid)=@OldOwner !-B$WAV
order by name =e*S h0dK
OPEN curObject <aSjK#
FETCH NEXT FROM curObject INTO @Name, @Owner 2:GS(%~
WHILE(@@FETCH_STATUS=0) I' [gGK4F
BEGIN p.)IdbC`B
if @Owner=@OldOwner '8Wu9 phT
begin mH6\8I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZW>iq M^9
exec sp_changeobjectowner @OwnerName, @NewOwner ~'lY Q[7
end 8GlRO4yd
-- select @name,@NewOwner,@OldOwner pd^"MG
FETCH NEXT FROM curObject INTO @Name, @Owner ;2N:
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END .:r
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close curObject [$]qJ~kz
deallocate curObject @}\wec_
GO 6
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10、SQL SERVER中直接循环写入数据 Xnc?oT+
declare @i int }-/oL+j
set @i=1 0(qtn9;=2
while @i<30 0fE?(0pBj
begin yd|ao\'=
insert into test (userid) values(@i) yi.GD~69
set @i=@i+1 wNvq['P
end Ky[s&>02
小记存储过程中经常用到的本周,本月,本年函数 N||a0&&
Dateadd(wk,datediff(wk,0,getdate()),-1) 9KCeKT>v
Dateadd(wk,datediff(wk,0,getdate()),6) vFwhe!
Dateadd(mm,datediff(mm,0,getdate()),0) zoibinm}Eg
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) OjWg>v\v
Dateadd(yy,datediff(yy,0,getdate()),0) uxx(WS
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !:2_y'hA
上面的SQL代码只是一个时间段 fD3>g{
Dateadd(wk,datediff(wk,0,getdate()),-1) T|k_$LH
Dateadd(wk,datediff(wk,0,getdate()),6) pgd9_'[5
就是表示本周时间段. {Ri6975
下面的SQL的条件部分,就是查询时间段在本周范围内的: 2=IZD `{!
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) s.$:.*k
而在存储过程中 1$_|h@
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cB0"vbdO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) -J":'xCP!