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。 2z=GKV
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一、基础 "K*+8IO2
1、说明:创建数据库 WX9pJ9d
CREATE DATABASE database-name +gsk}>"
2、说明:删除数据库 DU:
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drop database dbname d8T,33>T
3、说明:备份sql server #p^r)+\3=
--- 创建 备份数据的 device
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USE master !B\[Q$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' QWWoj[d#
--- 开始 备份 NurbioFL
BACKUP DATABASE pubs TO testBack Cb/?hT
4、说明:创建新表 BA+:}81&<q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) p; ZEz<M
根据已有的表创建新表: Q|W!m0XO
A:create table tab_new like tab_old (使用旧表创建新表) :j m|)
B:create table tab_new as select col1,col2... from tab_old definition only 7OOod1
5、说明:删除新表 tHo0q<.oX
drop table tabname 5`3f"(ay/
6、说明:增加一个列 .5m^)hi
Alter table tabname add column col type ^. i;,
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。 MB,P#7|
7、说明:添加主键: Alter table tabname add primary key(col) f3]u-e'b
说明:删除主键: Alter table tabname drop primary key(col) H9Pe,eHs
8、说明:创建索引:create [unique] index idxname on tabname(col....) 1yIo'i1
删除索引:drop index idxname .DkDMg1US
注:索引是不可更改的,想更改必须删除重新建。 L5*,l`lET
9、说明:创建视图:create view viewname as select statement "yCek
删除视图:drop view viewname A*:(%!
10、说明:几个简单的基本的sql语句 ,`JXBI~
选择:select * from table1 where 范围 oFeflcSz
插入:insert into table1(field1,field2) values(value1,value2) B<Ynx_95
删除:delete from table1 where 范围 V-(LHv
更新:update table1 set field1=value1 where 范围 8@a|~\3-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ljrA^P,>P
排序:select * from table1 order by field1,field2 [desc] ?ixzlDto\
总数:select count as totalcount from table1 #2!M+S
求和:select sum(field1) as sumvalue from table1 $PQlaivA
平均:select avg(field1) as avgvalue from table1 I({ 7a i
最大:select max(field1) as maxvalue from table1 \..(!>,%F
最小:select min(field1) as minvalue from table1 3*gWcPGe
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11、说明:几个高级查询运算词 K,IPVjS
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A: UNION 运算符 uGQCW\!"4
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。 ]&ptld;
B: EXCEPT 运算符 N2_ =^s7
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。 m~Dq0 T
C: INTERSECT 运算符 =;3|?J0=
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。 CFh&z^]PR
注:使用运算词的几个查询结果行必须是一致的。 u0J+Nj9
12、说明:使用外连接 o /fq
A、left outer join: DOWUnJ;5
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。 nWK"i\2#G
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 FZ^byIS[
B:right outer join: ::vw1Es
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。 +G_6Ek4
C:full outer join: B!le=V,@,
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。 =P+S]<O
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二、提升 Ac.z6]p
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) EVj48
法一:select * into b from a where 1<>1 9_ Qm_
法二:select top 0 * into b from a <][|,9mw
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) R^F99L
insert into b(a, b, c) select d,e,f from b; %;zWS/JhL
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) 5hp b=2
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 DrltxI)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. C_#0Y_O
4、说明:子查询(表名1:a 表名2:b) F
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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) 3@}HdLmN|
5、说明:显示文章、提交人和最后回复时间 N_VAdNJ^:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b YS{
6、说明:外连接查询(表名1:a 表名2:b) ,oP-:q!PC
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2+GF:[$
7、说明:在线视图查询(表名1:a ) 3a{QkVeV7
select * from (SELECT a,b,c FROM a) T where t.a > 1; hP,1;`[1
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 wrn[q{dX
select * from table1 where time between time1 and time2 ?k_=?m
select a,b,c, from table1 where a not between 数值1 and 数值2 "eQ9 6^'J
9、说明:in 的使用方法 !*|CIxk(
select * from table1 where a [not] in ('值1','值2','值4','值6') y::;e#.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ORx,n7-
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =QyO$:t
11、说明:四表联查问题: IFPywL{K
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ~ilbW|s?=k
12、说明:日程安排提前五分钟提醒 (p14{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N"t,6tH
13、说明:一条sql 语句搞定数据库分页 .(S,dG0P
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 /p>"|z
14、说明:前10条记录 ~N'KIP[W
select top 10 * form table1 where 范围 66'TdF]"
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) h)wR[N]n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~:)$~g7>b
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 :M3l#`4Q
(select a from tableA ) except (select a from tableB) except (select a from tableC) o-O/M S
17、说明:随机取出10条数据 XtfL{Fy|T
select top 10 * from tablename order by newid() 'KQuz)-
18、说明:随机选择记录 g\(7z
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select newid() wKY6[ vvF
19、说明:删除重复记录 A{6ZEQAh>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Y\p
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20、说明:列出数据库里所有的表名 Lp
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select name from sysobjects where type='U' ~82jL%-u
21、说明:列出表里的所有的 (rwbF
select name from syscolumns where id=object_id('TableName') xJ&StN/'
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。 82)d.>
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 ]K9x<@!
显示结果: j9u-C/Q\r
type vender pcs ;v0sM*x%V
电脑 A 1 yJp&A
电脑 A 1 W: ?-d{
光盘 B 2 WejY
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光盘 A 2 ',!#?aGV
手机 B 3 2qr%xK'^B
手机 C 3 N'`*#UI+
23、说明:初始化表table1 s\jLIrG8
TRUNCATE TABLE table1 6:EO
24、说明:选择从10到15的记录 2tr2:PB`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc pb{P[-f
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三、技巧 VS).!;>z
1、1=1,1=2的使用,在SQL语句组合时用的较多 XPEjMm'*b3
"where 1=1" 是表示选择全部 "where 1=2"全部不选, akqXh 9g
如: WJ.PPq>]F
if @strWhere !='' X2e|[MWkp
begin . t3@86xTJ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 2#!$f_
end vl*RRoJ
else S,8zh/1y
begin FD@! z
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' d=5D 9'+
end Zh(f2urKV
我们可以直接写成 QHM39Eu]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ./g0T{&
2、收缩数据库 vGAPQg6*
--重建索引 ?APzx@$D.
DBCC REINDEX ~b7Nzzfo
DBCC INDEXDEFRAG s=q+3NTv
--收缩数据和日志 -xcz+pHQ
DBCC SHRINKDB 1OGlD+f
DBCC SHRINKFILE NfO0^^"
3、压缩数据库 FFQF0.@EBi
dbcc shrinkdatabase(dbname) 2)8lJXM$L
4、转移数据库给新用户以已存在用户权限 k{bba=<
exec sp_change_users_login 'update_one','newname','oldname' q/3}8BJ
go F@I_sGCcb
5、检查备份集 Va 5U`0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' uVO9r-O8p
6、修复数据库 JV/,QWar
ALTER DATABASE [dvbbs] SET SINGLE_USER ~T-.k
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GO u3ZG;ykM
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK eQLa .0
GO vB
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ALTER DATABASE [dvbbs] SET MULTI_USER 16+@#d%#p
GO @KpzxcEoO
7、日志清除 l1:j/[B=
SET NOCOUNT ON T#BOrT>V
DECLARE @LogicalFileName sysname, *@ o3{0[Z
@MaxMinutes INT, @1+/r?b
@NewSize INT WIGb7}egR
USE tablename -- 要操作的数据库名 t!=S[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 fBF}-{VX(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. vK{K#{
@NewSize = 1 -- 你想设定的日志文件的大小(M) "_l[4o[D
-- Setup / initialize 0PfFli`2;
DECLARE @OriginalSize int ]d[q:N]z
SELECT @OriginalSize = size +|?c_vD
FROM sysfiles |s^ar8)=)
WHERE name = @LogicalFileName >r*Zm2($MR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + s=nds"J
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + c1<g!Q&E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7/1S5yUr|
FROM sysfiles ?~K2&eo
WHERE name = @LogicalFileName :U*[s$
CREATE TABLE DummyTrans fr?eOigbl
(DummyColumn char (8000) not null) 'I~dJEW7
DECLARE @Counter INT, MQ+ek4
@StartTime DATETIME, 5R Hs
@TruncLog VARCHAR(255) Iu[EUi!"
SELECT @StartTime = GETDATE(), f
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6:!fyia
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ZJpI]^9|
EXEC (@TruncLog) lV
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-- Wrap the log if necessary. |<V{$),k
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9mnON~j5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 0%t|?@HoN
AND (@OriginalSize * 8 /1024) > @NewSize xH0/R LK3J
BEGIN -- Outer loop. xki"'
SELECT @Counter = 0 ,*4"d._Y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) NLpD,q{
BEGIN -- update G#V22Wca8
INSERT DummyTrans VALUES ('Fill Log') >H1d9y+Z
DELETE DummyTrans s`B'vyoaa
SELECT @Counter = @Counter + 1 kMo)4Xp
END dF,FH-
EXEC (@TruncLog) 5^dw!^d
END C;5}/J^E
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 1fy{@j(W
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =FbfV*K9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' pUr[MnQLf
FROM sysfiles 7" [;M
WHERE name = @LogicalFileName LZVO9e]
DROP TABLE DummyTrans x\DkS,O
SET NOCOUNT OFF US|vYd}u+
8、说明:更改某个表 0o]K6b
exec sp_changeobjectowner 'tablename','dbo' >+#[O"
9、存储更改全部表 f3>/6C
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ,2`d3u^CW
@OldOwner as NVARCHAR(128), "Pc,+>vh
@NewOwner as NVARCHAR(128) W24bO|>D
AS hvyN8We
DECLARE @Name as NVARCHAR(128) ,7(/Il9
DECLARE @Owner as NVARCHAR(128) `O{Uz?#*x
DECLARE @OwnerName as NVARCHAR(128) $-RhCnE
DECLARE curObject CURSOR FOR 9zyN8v2
select 'Name' = name, Mb>XM7}PU
'Owner' = user_name(uid) +7^Ul6BB#K
from sysobjects ttnXEF
where user_name(uid)=@OldOwner 3(:mRb}
order by name v,+@
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OPEN curObject 0Nu]N)H5<l
FETCH NEXT FROM curObject INTO @Name, @Owner ,&=`T7i
WHILE(@@FETCH_STATUS=0) x\rZoF.NQ
BEGIN [f0HUbPX
if @Owner=@OldOwner }'W^Ki$
begin |DW'RopM
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ]S L&x:/-
exec sp_changeobjectowner @OwnerName, @NewOwner OK\%cq/U
end co3 ,8\N0
-- select @name,@NewOwner,@OldOwner 4m*(D5Y=|
FETCH NEXT FROM curObject INTO @Name, @Owner $<4Ar*i
END wM)w[
close curObject I[UA' ~f
deallocate curObject k%g xY% 0
GO )US/bC!M$
10、SQL SERVER中直接循环写入数据 `<zb
declare @i int .F2nF8
set @i=1 9pcf jx..
while @i<30 .6NSt
begin hYn'uL^~[
insert into test (userid) values(@i) X6 ,9D[Nw
set @i=@i+1 =!^iiHF
end @<G/H|f
小记存储过程中经常用到的本周,本月,本年函数 $k ma#7
Dateadd(wk,datediff(wk,0,getdate()),-1) 7]%il[
Dateadd(wk,datediff(wk,0,getdate()),6) (;&?B.<\:
Dateadd(mm,datediff(mm,0,getdate()),0) R3n&o%$*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Ij1]GZ`A(
Dateadd(yy,datediff(yy,0,getdate()),0) k+[KD >;1
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) +c a296^
上面的SQL代码只是一个时间段 -ZP&zOsDr
Dateadd(wk,datediff(wk,0,getdate()),-1) gKN_~{{OD
Dateadd(wk,datediff(wk,0,getdate()),6) b3xkJ&Z
就是表示本周时间段. j/D)UWkR
下面的SQL的条件部分,就是查询时间段在本周范围内的: \`&pk-uW
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) P(epG?Qg
而在存储过程中 ib\[ ~rg
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Wk?|BR]O
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) N[bN"'U/1