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。 Noh?^@T`Ov
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一、基础 B;!f<"a8
1、说明:创建数据库 +yWR#[`n
CREATE DATABASE database-name RZO5=L9E
2、说明:删除数据库 Sj)}qM-y#
drop database dbname [Uli>/%JB
3、说明:备份sql server ?U_9{}r
--- 创建 备份数据的 device m"Qq{p|'
USE master ^mg*;8eGa
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [T`}yb@
--- 开始 备份 3sFeP&
BACKUP DATABASE pubs TO testBack 8Mu;U3cIW
4、说明:创建新表 U<47WfcW
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) BDe]18X
根据已有的表创建新表: #dc1pfL!y{
A:create table tab_new like tab_old (使用旧表创建新表) )p8I@E
B:create table tab_new as select col1,col2... from tab_old definition only B,_`btJh
5、说明:删除新表 ''S&e
drop table tabname -#?<05/C>
6、说明:增加一个列 qzK("d
Alter table tabname add column col type xQu
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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。 /APcL5:=
7、说明:添加主键: Alter table tabname add primary key(col) wGJjA=C
说明:删除主键: Alter table tabname drop primary key(col) knT.l"
8、说明:创建索引:create [unique] index idxname on tabname(col....) m&IsDAn
删除索引:drop index idxname %M&3VQ9w
注:索引是不可更改的,想更改必须删除重新建。 aqMc6N`z
9、说明:创建视图:create view viewname as select statement t)N;'v &
删除视图:drop view viewname DA"}A`HfI
10、说明:几个简单的基本的sql语句 @T&t.|`
选择:select * from table1 where 范围 @Z;1 g
插入:insert into table1(field1,field2) values(value1,value2) F
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删除:delete from table1 where 范围 Y-p<qL|_
更新:update table1 set field1=value1 where 范围 lJ{V
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! +;q.Y?
排序:select * from table1 order by field1,field2 [desc] H9`
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总数:select count as totalcount from table1 PJgp+u<
求和:select sum(field1) as sumvalue from table1 #U=;T]!'$
平均:select avg(field1) as avgvalue from table1 \t3qS
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最大:select max(field1) as maxvalue from table1 4:mCXP,x
最小:select min(field1) as minvalue from table1 |NrrTN?>
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11、说明:几个高级查询运算词 f:xWu-
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A: UNION 运算符 F9H~k"_ZJR
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。 :gI.l1
B: EXCEPT 运算符 a3@w|KLt
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。 lj2=._@R
C: INTERSECT 运算符 1f4bt6[
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。 ;/LD)$_
注:使用运算词的几个查询结果行必须是一致的。 u+D[_yd^
12、说明:使用外连接 kWL.ewTiex
A、left outer join: 4;KWG}~[o
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ._CP%
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <7n]Ai@Y
B:right outer join: 1H{jy^sP 7
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 u3ZCT" !
C:full outer join: DQJG,?e{
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 pCU*@c!
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二、提升 61_f3S(u
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Vq ^]s$'
法一:select * into b from a where 1<>1 ~`eHHgX
法二:select top 0 * into b from a }/e`v6
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~xyw>m+o.
insert into b(a, b, c) select d,e,f from b; v6uxxsI>Hm
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) )1F<6R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 'C?NJ~MN
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Qw)9r{f
4、说明:子查询(表名1:a 表名2:b) bJ3(ckhq
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) M>l^%`
5、说明:显示文章、提交人和最后回复时间 R,Oe$J<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {6
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6、说明:外连接查询(表名1:a 表名2:b) Zzj0\?Ul
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }
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7、说明:在线视图查询(表名1:a ) Yrn"saVc,
select * from (SELECT a,b,c FROM a) T where t.a > 1; A6UO0lyu
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 uDayBaR
select * from table1 where time between time1 and time2 oRq!=eUu_
select a,b,c, from table1 where a not between 数值1 and 数值2 2KI!af[I
9、说明:in 的使用方法 ]hTb@.
select * from table1 where a [not] in ('值1','值2','值4','值6') l@~LV}BI
10、说明:两张关联表,删除主表中已经在副表中没有的信息 RL}KAGK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) YQ(Po!NI\'
11、说明:四表联查问题: Z=+03
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... NZXjE$<Vr
12、说明:日程安排提前五分钟提醒 Lz4ehWntO
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "uD=KlA
13、说明:一条sql 语句搞定数据库分页 ZR3nK0
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 lDc;__}Ws
14、说明:前10条记录 . (`3JQ2s
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.) 3qMNl>>
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 4]XI"-M^D
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 8SmjZpQ?
(select a from tableA ) except (select a from tableB) except (select a from tableC) UG[e//m
17、说明:随机取出10条数据 -50AX1h31:
select top 10 * from tablename order by newid() ;Zut@z4\
18、说明:随机选择记录 p25Fn`}H
select newid() +,flE=5]s
19、说明:删除重复记录 >3D7tK(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 ;")A{tX2
select name from sysobjects where type='U' 8cVzFFQP
21、说明:列出表里的所有的 5EeDHsvV9
select name from syscolumns where id=object_id('TableName') O`W%Tr
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。 H[Weu
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 g-)mav
显示结果: cT'w=
type vender pcs GJQc!cqk
电脑 A 1 Yx)o:#2
电脑 A 1 ;vp\YIeX1
光盘 B 2 SUdm 0y
光盘 A 2 TEVI'%F
手机 B 3 XutF"9u
手机 C 3 ]~c+'E`
23、说明:初始化表table1 Ruaur]
TRUNCATE TABLE table1 8{I"q[GZ
24、说明:选择从10到15的记录 rT7^-B*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc =@r--E
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三、技巧 pGWA\}'
1、1=1,1=2的使用,在SQL语句组合时用的较多 ff cLuXa
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @}LZ! y
如: RA/EpD:H
if @strWhere !='' ps1@d[n
begin l";'6;g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere L-h$Z0]_F
end oXY Moi
else x:z0EYL
begin WjMRH+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' =dH$2W)G
end HFtf
我们可以直接写成 1]OSWCEm*[
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere UuJjO^t
2、收缩数据库 V[hK2rVH.
--重建索引 \,xFg w4
DBCC REINDEX m *X7T
DBCC INDEXDEFRAG -l*g~7|j
--收缩数据和日志 Fi;VDK(V9
DBCC SHRINKDB ^Udv]Wh
DBCC SHRINKFILE ;Ss$2V'a
3、压缩数据库 y{=NP
dbcc shrinkdatabase(dbname) -q>^ALf|@>
4、转移数据库给新用户以已存在用户权限 /g.]RY+u|x
exec sp_change_users_login 'update_one','newname','oldname' Tj/GClD:%
go !,&yyx.
5、检查备份集 EESN\_{~.
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' G*n2Ii
6、修复数据库 j$@tK0P
ALTER DATABASE [dvbbs] SET SINGLE_USER %5B%KCCN
GO j4.&l3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wD9a#AgEd
GO H7&xLYQ2
ALTER DATABASE [dvbbs] SET MULTI_USER >)4YP*qIPb
GO zICI_*~
7、日志清除 8k!6b\Imz
SET NOCOUNT ON *i%quMv
DECLARE @LogicalFileName sysname, Jh@_9/?
@MaxMinutes INT, tS?lB05TOR
@NewSize INT 5vOC CW
USE tablename -- 要操作的数据库名 T0e<Slo~C
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ST',4Oph5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $&{IKP)u
@NewSize = 1 -- 你想设定的日志文件的大小(M) *y7 $xa4
-- Setup / initialize Y94MI1O5$
DECLARE @OriginalSize int H5xzD9K;/C
SELECT @OriginalSize = size x0+glQrNN
FROM sysfiles _"N\b%CkO
WHERE name = @LogicalFileName !`wW_W
SELECT 'Original Size of ' + db_name() + ' LOG is ' + *e4TSqC|
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + r/r:oXK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S%6U~@hig
FROM sysfiles *"9<TSU%m
WHERE name = @LogicalFileName _%pAlo_6
CREATE TABLE DummyTrans ]T<^{jG
(DummyColumn char (8000) not null) oyeG$mpg
DECLARE @Counter INT, YD_]!HK}
@StartTime DATETIME, AFm1t2,+;
@TruncLog VARCHAR(255) Y
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SELECT @StartTime = GETDATE(), uHM@h{r
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >L>+2z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 1/iE`Si
EXEC (@TruncLog) cf;Ht^M\
-- Wrap the log if necessary. AtHS@p
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired uofLhy!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) f(Hu {c5yV
AND (@OriginalSize * 8 /1024) > @NewSize +=fKT,-*G!
BEGIN -- Outer loop. i/qTFQst
_
SELECT @Counter = 0 JOfV]eCL
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) kW-81
BEGIN -- update FC>d_=V
INSERT DummyTrans VALUES ('Fill Log') #gv4
DELETE DummyTrans +;gsRhWk
SELECT @Counter = @Counter + 1 @.$MzPQQI
END );JJ2Jlkd
EXEC (@TruncLog) TSto9$}*
END .[j%sGdKl
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;VzMU ;j
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + +Ui_ O
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |nxdB&1n
FROM sysfiles 5
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WHERE name = @LogicalFileName Mq\~`8V
DROP TABLE DummyTrans '044Vm;/
SET NOCOUNT OFF optBA3@e!
8、说明:更改某个表 z+VV}:Q
exec sp_changeobjectowner 'tablename','dbo' s>[{}7ca
9、存储更改全部表 p@I9<^"
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch h)dRR_
@OldOwner as NVARCHAR(128), /1.rz{wpb
@NewOwner as NVARCHAR(128) U{#xW
AS b9("DZW;
DECLARE @Name as NVARCHAR(128) \
P/W8{
DECLARE @Owner as NVARCHAR(128) kC$I2[ t!
DECLARE @OwnerName as NVARCHAR(128) O|z%DkH[
DECLARE curObject CURSOR FOR |C-y}iQ:6~
select 'Name' = name, u-><}OVf~
'Owner' = user_name(uid) TOT
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from sysobjects S/Oxr%H
where user_name(uid)=@OldOwner oXGZK5w<l
order by name 2Rptxb_@
OPEN curObject MCy~@)-IN
FETCH NEXT FROM curObject INTO @Name, @Owner 4rp6 C/i
WHILE(@@FETCH_STATUS=0) ]VjLKFb~U
BEGIN U^$E'Q-VK
if @Owner=@OldOwner -2*>`,Uu
begin !,bPe5?Ql
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &]NZvqdj.]
exec sp_changeobjectowner @OwnerName, @NewOwner |63Y
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end Bc
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-- select @name,@NewOwner,@OldOwner z`#_F}v,m/
FETCH NEXT FROM curObject INTO @Name, @Owner o)I/P<
END Fd8hGj1
close curObject buYDl
deallocate curObject _s>^?x}
GO >t#\&|9I
10、SQL SERVER中直接循环写入数据 p;->hn~D'5
declare @i int 0dt"ZSm
set @i=1 >oY^Gx
while @i<30 dR[o|r
begin ^k72{ 3N(
insert into test (userid) values(@i) "c
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set @i=@i+1 QJXdb]Y^;
end 8/q*o>[?
小记存储过程中经常用到的本周,本月,本年函数 Pj!%ym3A
Dateadd(wk,datediff(wk,0,getdate()),-1) !S,pRS+
Dateadd(wk,datediff(wk,0,getdate()),6) R^tcr)(
Dateadd(mm,datediff(mm,0,getdate()),0) fVUKvZ}P*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) L@A9{,9Pl
Dateadd(yy,datediff(yy,0,getdate()),0) S0xIvzS
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) x#
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上面的SQL代码只是一个时间段 h48 bb.p2
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) !-(J-45
就是表示本周时间段. {B^pnLc
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4ftj>O
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) zoXuFg
而在存储过程中 l1RlYl5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `|,tCM&-
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) AM/lbMr