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。 gjk=`lU
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一、基础 3-FS} {,
1、说明:创建数据库 N|WnUlf]:
CREATE DATABASE database-name x{&0:|bCs6
2、说明:删除数据库 A|c :&i
drop database dbname $Vlfg51 ob
3、说明:备份sql server %]nLCoQh
--- 创建 备份数据的 device 6 7~m9pk
USE master [yf2_{*0T
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 6JSa:Q>,
--- 开始 备份 @L,T/m-HF
BACKUP DATABASE pubs TO testBack d]}
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4、说明:创建新表 zZ[SC
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z:&"Ax
根据已有的表创建新表: b^;19]/RW
A:create table tab_new like tab_old (使用旧表创建新表) t9zPJQlT}
B:create table tab_new as select col1,col2... from tab_old definition only \# lh b
5、说明:删除新表 hUxpz:U*
drop table tabname cSnm \f
6、说明:增加一个列 k9w<0h3
Alter table tabname add column col type 0/#XUX 4
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "mSDL:$
7、说明:添加主键: Alter table tabname add primary key(col) O_FT@bo\
说明:删除主键: Alter table tabname drop primary key(col) .KIAeCvl\
8、说明:创建索引:create [unique] index idxname on tabname(col....) Q4Hf!v]r
删除索引:drop index idxname pz:$n_XC}
注:索引是不可更改的,想更改必须删除重新建。 0v,DQJ?w8
9、说明:创建视图:create view viewname as select statement `Z{;
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删除视图:drop view viewname I`5F&8J{
10、说明:几个简单的基本的sql语句 L` V6\Ix(I
选择:select * from table1 where 范围 o`DBzC
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 !-|&
更新:update table1 set field1=value1 where 范围 d9R0P2
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yaa+j8s]
排序:select * from table1 order by field1,field2 [desc] =9LC"eI&|
总数:select count as totalcount from table1 \V7Hi\)
求和:select sum(field1) as sumvalue from table1 3`5?Zgp
平均:select avg(field1) as avgvalue from table1 3BKW
最大:select max(field1) as maxvalue from table1 Ad+-/hxc
最小:select min(field1) as minvalue from table1 bsR^H5O@
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11、说明:几个高级查询运算词 st:[|`
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A: UNION 运算符 )tz8(S
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。 Y~,[9:SR
B: EXCEPT 运算符 XqyfeY5t
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。 VCX})sp
C: INTERSECT 运算符 0d9rJv}~
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。 +VAfT\G2
注:使用运算词的几个查询结果行必须是一致的。 3S_KycE{
12、说明:使用外连接 Yu9Ccj`
A、left outer join: X. UN=lu
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。 hkRv0q.'
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 Ipb4{A&"\
B:right outer join: U:J~Oy_Z
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。 hh |'Uq3
C:full outer join: `Rm2G
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。 [A
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二、提升 sq@Eu>Ng(X
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )m\%L`+
法一:select * into b from a where 1<>1 +4GuA0N6
法二:select top 0 * into b from a wAVO%8u
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) tqmM7$}}P
insert into b(a, b, c) select d,e,f from b; s%H5Qa+Uh
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 1&i!92:E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P+%O]v1 Ob
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 9cQKXh:R.
4、说明:子查询(表名1:a 表名2:b) <Zl0$~B:5
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) ]\+bx=
5、说明:显示文章、提交人和最后回复时间 Gvtd )9^<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V tZ
6、说明:外连接查询(表名1:a 表名2:b) x|F6^d
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-E+/.A
7、说明:在线视图查询(表名1:a ) SXwgn >
select * from (SELECT a,b,c FROM a) T where t.a > 1; fx99@%Ii
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 S]K^wj[
select * from table1 where time between time1 and time2 ]m=* =LLC
select a,b,c, from table1 where a not between 数值1 and 数值2 R)nhgp(~
9、说明:in 的使用方法 [LjYLm%<
select * from table1 where a [not] in ('值1','值2','值4','值6') v9x $`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 n"@3d.21
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4w*F!E2H\}
11、说明:四表联查问题: /+JCi6{sHS
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ag:#82C
12、说明:日程安排提前五分钟提醒 JBeC\ \QX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 OAOG&6xu8
13、说明:一条sql 语句搞定数据库分页 f*NtnD=rJ
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 (J\D"4q
14、说明:前10条记录 b?B"u^b!
select top 10 * form table1 where 范围 vTh-I&}:
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) d,8V-Dk+p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) `axNeqM
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 3P^eD:)
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(select a from tableA ) except (select a from tableB) except (select a from tableC) `if*
17、说明:随机取出10条数据 n!ea)+^
select top 10 * from tablename order by newid() r1}7Q7-z
18、说明:随机选择记录 u32wS$*8
select newid() W=GNo9:
19、说明:删除重复记录 feQ_dA q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) o!sxfJKl
20、说明:列出数据库里所有的表名 rYJt;/RtR}
select name from sysobjects where type='U' jcXb@FE6
21、说明:列出表里的所有的 L7X._XBO[
select name from syscolumns where id=object_id('TableName') TcauCL
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。 UF 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 ;=_<\2
显示结果: C]A*B
type vender pcs hy
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电脑 A 1 q/m}+v]
电脑 A 1 z* zLK[t+
光盘 B 2 u'yePJTE
光盘 A 2 [9[tn-
手机 B 3 |pq z(j7
手机 C 3 _^#PV}
23、说明:初始化表table1 +\"@2mOH{+
TRUNCATE TABLE table1 WuSRA<{P
24、说明:选择从10到15的记录 o1GWcxu*\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?9mWMf%t
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 qe`W~a9x
"where 1=1" 是表示选择全部 "where 1=2"全部不选, cvn,&G-`
如: ZS^EKz~ +
if @strWhere !='' ?uk|x!Ko]
begin b]hRmW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =1VY/sv
end 1?E\2t&K
else goRoi\z $
begin r/:9j(yxr
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :d)@|SR1
end %+o]1R
我们可以直接写成 ~qFi0<-M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere pC_2_,6$
2、收缩数据库 $Snwx
--重建索引 GrVvOJr
DBCC REINDEX 8eWb{nuJ>
DBCC INDEXDEFRAG w2/%e$D!9
--收缩数据和日志 J\m7U
DBCC SHRINKDB m[ifcDZ(e
DBCC SHRINKFILE ;,Lq*x2s
3、压缩数据库 s8.oS);`
dbcc shrinkdatabase(dbname) hCW8(Zt
4、转移数据库给新用户以已存在用户权限 @ mtv2P`
exec sp_change_users_login 'update_one','newname','oldname' B quyPG"
go B:^5W{
5、检查备份集 {BJ[h
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dRWp/3 }
6、修复数据库 *AZC{jP
ALTER DATABASE [dvbbs] SET SINGLE_USER DFE?H
GO @@SG0YxZ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A' dt
WD
GO WdunI~&.
ALTER DATABASE [dvbbs] SET MULTI_USER rh$%*l
GO dYfVox;
7、日志清除 ]7h&ZF
SET NOCOUNT ON An/)|B4
DECLARE @LogicalFileName sysname, ZLE4XB]
@MaxMinutes INT, s49AF
@NewSize INT w
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USE tablename -- 要操作的数据库名 pBK[j([
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 f{*G%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]E[Mv}
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@NewSize = 1 -- 你想设定的日志文件的大小(M) gmJJ(}HVz
-- Setup / initialize 3o"~_l$z
DECLARE @OriginalSize int R%7k<1d'`
SELECT @OriginalSize = size -qid.
FROM sysfiles 'hU&$lgMF
WHERE name = @LogicalFileName a l#yc
SELECT 'Original Size of ' + db_name() + ' LOG is ' + *(D_g!a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + CFRo>G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z~z.J]
FROM sysfiles DC[-<:B
WHERE name = @LogicalFileName ;9B:E"K?@1
CREATE TABLE DummyTrans }6^(
(DummyColumn char (8000) not null) B0Xn9Tvk
DECLARE @Counter INT, Q'$aFl'NR
@StartTime DATETIME, zzq/%jki
@TruncLog VARCHAR(255) ?w3f;v
SELECT @StartTime = GETDATE(), JK[7&C-O
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' XK(<N<Z@|e
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ew}C*4qH
EXEC (@TruncLog) }1X,~y]
-- Wrap the log if necessary. A
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 9FJU'$FN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) h+N75
AND (@OriginalSize * 8 /1024) > @NewSize c @2s!bs
BEGIN -- Outer loop. l$zo3[
SELECT @Counter = 0 LR-op?W
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
LL kAA?P
BEGIN -- update ;rd!kFd#bq
INSERT DummyTrans VALUES ('Fill Log') x<9|t(
DELETE DummyTrans a&PoUwG
SELECT @Counter = @Counter + 1 0o`0Td
END TtkB
EXEC (@TruncLog) E$smr\
END Oyj!N`&z@
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2\EMtR>.M'
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |iO2,99i
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 8M(N
FROM sysfiles 0~an\4nh
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans )Bd+jli|s
SET NOCOUNT OFF QJOP *<O
8、说明:更改某个表 G}}oeS
exec sp_changeobjectowner 'tablename','dbo' >Pbd#*
9、存储更改全部表 (W*yF2r
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch o7]h;Zg5r
@OldOwner as NVARCHAR(128), w;>]L.n
@NewOwner as NVARCHAR(128) U/0NN>V
AS "QGP]F
DECLARE @Name as NVARCHAR(128) fv<($[0
DECLARE @Owner as NVARCHAR(128) f8'&(-
DECLARE @OwnerName as NVARCHAR(128) 9I^_n+E
DECLARE curObject CURSOR FOR gy9!T(z
select 'Name' = name, pS0-<-\R
'Owner' = user_name(uid) hvZW~
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from sysobjects GW.s\8w
where user_name(uid)=@OldOwner ) ,*&rd!
order by name A+;]# 1y(D
OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner 1c?,= ;>
WHILE(@@FETCH_STATUS=0) :q^g+Bu=
BEGIN >{npg2
if @Owner=@OldOwner NTgk0cq
begin ]!h%Jlu
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 3lA<{m;V
exec sp_changeobjectowner @OwnerName, @NewOwner k{"~G#GwP
end ZNG.W0{p
-- select @name,@NewOwner,@OldOwner |Q.?<T:wt=
FETCH NEXT FROM curObject INTO @Name, @Owner /$I&D}uR`
END _%Mu{Ni&
close curObject %)\Cwl
deallocate curObject DRf~l9f
GO B3XVhUP
10、SQL SERVER中直接循环写入数据 %Ljc#AVg
declare @i int fN8A'p[
set @i=1 N#]f?6*R
while @i<30 _xUiHX<
begin /c__{?go
insert into test (userid) values(@i) 1cOp"!
set @i=@i+1 a,lH6lDk
end L-G186B$r
小记存储过程中经常用到的本周,本月,本年函数 *C's7O{O
Dateadd(wk,datediff(wk,0,getdate()),-1) LFV;Y.-(h
Dateadd(wk,datediff(wk,0,getdate()),6) HHa7Kh|-H
Dateadd(mm,datediff(mm,0,getdate()),0) +(UrqK4Av
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) [-vd]ob
Dateadd(yy,datediff(yy,0,getdate()),0) fs>0{
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) o.}^6.h"
上面的SQL代码只是一个时间段 &&JI$x0;
Dateadd(wk,datediff(wk,0,getdate()),-1) <fs2;
Dateadd(wk,datediff(wk,0,getdate()),6) klJDYFX=HK
就是表示本周时间段. ] p'+F
下面的SQL的条件部分,就是查询时间段在本周范围内的: M}/%t1^g:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cGOE $nL
而在存储过程中 <Hm:#<\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?CL1^N%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) pB?a5jpA