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。 68
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一、基础 FES_:?.0
1、说明:创建数据库 Umx~!YL!
CREATE DATABASE database-name 5+*MqO>
2、说明:删除数据库 f8yE>qJP
drop database dbname 7\>P@s
3、说明:备份sql server D#}t)$"
--- 创建 备份数据的 device !sWKi)1
USE master \ vj<9ke&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' JDcc`&`M
--- 开始 备份 ]hNio6CVm
BACKUP DATABASE pubs TO testBack -j1?lY
4、说明:创建新表 t*Hr(|.
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5VD(fW[OW]
根据已有的表创建新表: hTZ&
A:create table tab_new like tab_old (使用旧表创建新表) }71a3EUK
B:create table tab_new as select col1,col2... from tab_old definition only UnSi= uj
5、说明:删除新表 +XV7W=
drop table tabname coa+@g,w7#
6、说明:增加一个列 }+/j /es{]
Alter table tabname add column col type 1t&LNIc|^
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 g\_J
7、说明:添加主键: Alter table tabname add primary key(col) xQLVFgd
说明:删除主键: Alter table tabname drop primary key(col) rCt8Q&mzf
8、说明:创建索引:create [unique] index idxname on tabname(col....) P2la/jN
删除索引:drop index idxname Er /:iO)_
注:索引是不可更改的,想更改必须删除重新建。 T<:mG%Is
9、说明:创建视图:create view viewname as select statement \4$V;C/n,
删除视图:drop view viewname 8t)5b.PS
10、说明:几个简单的基本的sql语句 SI_u0j4%*
选择:select * from table1 where 范围 @JB9qT
插入:insert into table1(field1,field2) values(value1,value2) P1cI]rriW
删除:delete from table1 where 范围 RuyqB>[o
更新:update table1 set field1=value1 where 范围 %gBulvg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! v\&C]W]
排序:select * from table1 order by field1,field2 [desc] N@}5Fnk-
总数:select count as totalcount from table1 p;#@#>h
求和:select sum(field1) as sumvalue from table1 1ym^G0"s
平均:select avg(field1) as avgvalue from table1 `Vph=`0
最大:select max(field1) as maxvalue from table1 ;iA6[uz
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 V46=48K.
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A: UNION 运算符 {"rYlN7,
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。 MS Qz,nn
B: EXCEPT 运算符 V
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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。 \S5YS2,P
C: INTERSECT 运算符 ]2zzY::Sd=
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。 KOv?p@d
注:使用运算词的几个查询结果行必须是一致的。 "W71#n+[
12、说明:使用外连接 "}|&eBH^<
A、left outer join: FaA'%P@
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。 V^S` d8?
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 5xb1FH d:
B:right outer join: BYuoeN!
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。 ta;q{3fe
C:full outer join: $u"*n\k>
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。 bM@8[&ta
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二、提升 z5tOsU
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +uqP:z
法一:select * into b from a where 1<>1 S+*%u/;l
法二:select top 0 * into b from a s[dq-pc"
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 0?80V'
insert into b(a, b, c) select d,e,f from b; K?J?]VCw
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) >Hd Pcsl L
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 V#Pz`D
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [TaYNc!\
4、说明:子查询(表名1:a 表名2:b) gH
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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) _~}n(?>
5、说明:显示文章、提交人和最后回复时间 GZx?vSoHh
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Y^(NzN
6、说明:外连接查询(表名1:a 表名2:b) PrQs_tNi
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `VL<pqPP
7、说明:在线视图查询(表名1:a ) yN/Uyhq
select * from (SELECT a,b,c FROM a) T where t.a > 1; 6\5"36&/rQ
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 w8KVs\/
select * from table1 where time between time1 and time2 b%_[\((
select a,b,c, from table1 where a not between 数值1 and 数值2 4*9WxhJ ]0
9、说明:in 的使用方法 <#ZDA/G(
select * from table1 where a [not] in ('值1','值2','值4','值6') oMV^W^<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 XEpwk,8*g
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) j0(+Kq:J
11、说明:四表联查问题: |+h8g@;Z
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 ..... #U?=D/
12、说明:日程安排提前五分钟提醒 q% pjY
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "raC?H
13、说明:一条sql 语句搞定数据库分页 n[c/L8j
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 dk@j!-q^
14、说明:前10条记录 ~=Q|EhF5
select top 10 * form table1 where 范围
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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.) *nYb9.T]i
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w=}R'O;k
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 6i=Nk"d
(select a from tableA ) except (select a from tableB) except (select a from tableC) Z5[f
17、说明:随机取出10条数据 Z.{r%W{2
select top 10 * from tablename order by newid() UEh-k"
18、说明:随机选择记录 r4wnfy
select newid() Y)KO*40c
19、说明:删除重复记录 ;sZHE&+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) V+dFL9
20、说明:列出数据库里所有的表名 R)u ${
select name from sysobjects where type='U' yq,%ey8
21、说明:列出表里的所有的 kFZjMchm A
select name from syscolumns where id=object_id('TableName') >G<.^~o
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 se^(1R k
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type \*x=q20
显示结果: YA'_Ba(v)
type vender pcs P%^\<#Ya7
电脑 A 1 n<3*7/-
电脑 A 1 C+<z;9`
光盘 B 2 P6([[mmG
光盘 A 2 I]B[H6
手机 B 3 {WYmO1
手机 C 3 Z`97=:W
23、说明:初始化表table1 1u\kxlZ
TRUNCATE TABLE table1 Mz:t[rfs
24、说明:选择从10到15的记录 ,Y_[+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @ZFU< e$!
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三、技巧 HZ.Jc"+M
1、1=1,1=2的使用,在SQL语句组合时用的较多 }N}\<RG
"where 1=1" 是表示选择全部 "where 1=2"全部不选, D-!#TN`Y
如: J`@#yHL
if @strWhere !='' PdNxuy
begin Vo-]&u&cr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere @Tl!A1y?
end 76M`{m
else #Ies
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begin dtT2h>h9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !YJ^BI
end sJ(q.FRM'
我们可以直接写成 DZ9qIc}Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;N/=)m
2、收缩数据库 O&c~7tM%
--重建索引 Z<t(h=?
DBCC REINDEX }bxx]rDl
DBCC INDEXDEFRAG fpK`
--收缩数据和日志 GP/Gv
DBCC SHRINKDB xK8R![x
DBCC SHRINKFILE 1>1ii
3、压缩数据库 ie+746tFW
dbcc shrinkdatabase(dbname) e2xqKG
4、转移数据库给新用户以已存在用户权限 te b~KM
exec sp_change_users_login 'update_one','newname','oldname' :/
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go {=K u9\
5、检查备份集 EjYCOb-
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' rH<iUiA?O
6、修复数据库 LpJ_HU7@lk
ALTER DATABASE [dvbbs] SET SINGLE_USER m#oZu {
GO Hx]{'?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cLD-,v;c
GO s`$px2Gw
ALTER DATABASE [dvbbs] SET MULTI_USER +J~q:b.
GO fDa$TbhjI
7、日志清除 fWBI}~e
SET NOCOUNT ON qt#a_F*rV
DECLARE @LogicalFileName sysname, jSj
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@MaxMinutes INT, I@f">&^
@NewSize INT
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USE tablename -- 要操作的数据库名 $]05?JY#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pSq3\#Twr
@MaxMinutes = 10, -- Limit on time allowed to wrap log. y&.[Nt '+
@NewSize = 1 -- 你想设定的日志文件的大小(M) bh8IF,@a
-- Setup / initialize QzQTE-SQ
DECLARE @OriginalSize int Va1 eG]jQ
SELECT @OriginalSize = size M zLx2?
FROM sysfiles TZ7{cekQ
WHERE name = @LogicalFileName ?q%)8 E
SELECT 'Original Size of ' + db_name() + ' LOG is ' + srN>pO8u~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + k_=~ObA$g
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 3psCV=/z
FROM sysfiles 4^KoHeM6
WHERE name = @LogicalFileName j;O{Hvvz
CREATE TABLE DummyTrans SRN:!-
(DummyColumn char (8000) not null) .bm#|X)RO
DECLARE @Counter INT, T1y,L<7?
@StartTime DATETIME, ]xhmM1$
@TruncLog VARCHAR(255) C_[V[k0(
SELECT @StartTime = GETDATE(), s68EzFS
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;n*N9-|.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) m4@y58n=
EXEC (@TruncLog) C/Ig.KmXF{
-- Wrap the log if necessary. u_o>v{&i
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m<BL/7
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -o+_PL
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AND (@OriginalSize * 8 /1024) > @NewSize c?0uv2*Yh
BEGIN -- Outer loop. ]]s_ 8u3
SELECT @Counter = 0 2O|o%`?
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) F6T@YSP
BEGIN -- update gz[Ng> D+
INSERT DummyTrans VALUES ('Fill Log') [)`9euR%
DELETE DummyTrans BEM+FG
SELECT @Counter = @Counter + 1 NA`3
END XHO}(!l\
EXEC (@TruncLog) x7J|
END ]t|KFk!)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + aW3yl}`{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /h0<0b?i
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' fV3!x,H
FROM sysfiles S\Qh#yFT
WHERE name = @LogicalFileName 0>-l {4srs
DROP TABLE DummyTrans }[PbA4l.g
SET NOCOUNT OFF lC6#EU;
8、说明:更改某个表 "w`f>]YLA
exec sp_changeobjectowner 'tablename','dbo' _Bh-*l?K>
9、存储更改全部表 fp9ksxb@m
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch q<}5KY
@OldOwner as NVARCHAR(128), R,A|"Q
@NewOwner as NVARCHAR(128) o><~ .T=d&
AS .9WUp>
DECLARE @Name as NVARCHAR(128) <W vuW6
DECLARE @Owner as NVARCHAR(128) 5/mW:G,&
DECLARE @OwnerName as NVARCHAR(128) O#7fkL
DECLARE curObject CURSOR FOR )^)V yI`O
select 'Name' = name, %|Vo Zx ^
'Owner' = user_name(uid) 5SX0g(C
from sysobjects SV]M]CAe
where user_name(uid)=@OldOwner /U)w:B+p/g
order by name G`w,$:,
OPEN curObject 2?ZHWS>U
FETCH NEXT FROM curObject INTO @Name, @Owner 9L?EhDcDV
WHILE(@@FETCH_STATUS=0) /w!b2KwV
BEGIN p&_a kQj
if @Owner=@OldOwner v>g1\yIw
begin `R8~H7{I6
set @OwnerName = @OldOwner + '.' + rtrim(@Name) "[H9)aAj7
exec sp_changeobjectowner @OwnerName, @NewOwner '[5tc fG#z
end [_qBp:_j?s
-- select @name,@NewOwner,@OldOwner +F 6KGK[
FETCH NEXT FROM curObject INTO @Name, @Owner
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END 622mNY
close curObject .4F(Y_c
deallocate curObject "S[VtuxPCU
GO -H.;73Kb[
10、SQL SERVER中直接循环写入数据 7 m&M(ct
declare @i int yN~=3b>
set @i=1 ^gky i/z
while @i<30 .6$ST Ksr
begin f]5bAs
insert into test (userid) values(@i) X~G"TT$)
set @i=@i+1 /Rk5n
end )R,*
小记存储过程中经常用到的本周,本月,本年函数 ]$nJn+85@b
Dateadd(wk,datediff(wk,0,getdate()),-1) f|6%71
Dateadd(wk,datediff(wk,0,getdate()),6) G~4 ^`[elB
Dateadd(mm,datediff(mm,0,getdate()),0) yYdXAenQ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ":"M/v%F
Dateadd(yy,datediff(yy,0,getdate()),0) w^`n
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Fw"~f5O
上面的SQL代码只是一个时间段 Z1\_[GA
Dateadd(wk,datediff(wk,0,getdate()),-1) 2HQ'iEu$
Dateadd(wk,datediff(wk,0,getdate()),6) W
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就是表示本周时间段. ^n] tf9{I
下面的SQL的条件部分,就是查询时间段在本周范围内的: MQ\:/]a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) r7ywK9UL
而在存储过程中 Di-"y, [
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \~y>aYy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) NZeI qhj