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。 $4,6&dwg
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一、基础 x*)O<K
1、说明:创建数据库 @U5>w\
CREATE DATABASE database-name NDGBvb
2、说明:删除数据库 )Cfrqe1^
drop database dbname +2O_LPV$,
3、说明:备份sql server rNp#5[e
--- 创建 备份数据的 device Xpwom'
USE master MqH~L?~}|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2wvDC@
--- 开始 备份 eQj/)@B:V
BACKUP DATABASE pubs TO testBack F
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4、说明:创建新表 r U5'hK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) t,nB`g?
根据已有的表创建新表: #1R
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A:create table tab_new like tab_old (使用旧表创建新表) gvYs<,:
B:create table tab_new as select col1,col2... from tab_old definition only E3.s8}}
5、说明:删除新表 2_v>8B
drop table tabname :"]ei@
6、说明:增加一个列 $S{j}74[
Alter table tabname add column col type :LG%8Z{R
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 A4h/oMis
7、说明:添加主键: Alter table tabname add primary key(col) g.s oNqt=
说明:删除主键: Alter table tabname drop primary key(col) rg.if"o
8、说明:创建索引:create [unique] index idxname on tabname(col....) H)tDfk sq\
删除索引:drop index idxname F{tSfKy2
注:索引是不可更改的,想更改必须删除重新建。 ~G:7*:[b
9、说明:创建视图:create view viewname as select statement cw{[B%vw
删除视图:drop view viewname "-%H</
10、说明:几个简单的基本的sql语句 v^'~-^s
选择:select * from table1 where 范围 iSHl_/I<
插入:insert into table1(field1,field2) values(value1,value2) ;wrgpP3
删除:delete from table1 where 范围 _TF>c:m3
更新:update table1 set field1=value1 where 范围 =ndKG5
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! oJ:J'$W(
排序:select * from table1 order by field1,field2 [desc] ow"Xv
总数:select count as totalcount from table1 Gy%e%'
求和:select sum(field1) as sumvalue from table1 @35shLs
平均:select avg(field1) as avgvalue from table1 4fswx@l
最大:select max(field1) as maxvalue from table1 w3D_ c~
最小:select min(field1) as minvalue from table1 ^cm^JyS)
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11、说明:几个高级查询运算词 flqTx)xE
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A: UNION 运算符 mZyTo/\0
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。 wQT'~'kL
B: EXCEPT 运算符 6*7&X#gG
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。 _L":Wux
C: INTERSECT 运算符 bSfQH4F
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。 "Cb<~Dy
注:使用运算词的几个查询结果行必须是一致的。 6tguy
12、说明:使用外连接 c^y 1s*
A、left outer join: :F&WlU$L
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。 &
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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 #ZA
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B:right outer join: 43XuQg4
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。 wG
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C:full outer join: c3##:"wr
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。 S J5kA`
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二、提升 2B7&Ll\>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )Yml'?V"
法一:select * into b from a where 1<>1 ?}[keSEh>
法二:select top 0 * into b from a bd4q/w4q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .+>}},
insert into b(a, b, c) select d,e,f from b; x<(h9tB
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) JN_#
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 o9i\[Ul
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. GSp1,E2J
4、说明:子查询(表名1:a 表名2:b) e 3K
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) 8T4J^6
5、说明:显示文章、提交人和最后回复时间 PJ{.jWwD
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _Gu ;U@
6、说明:外连接查询(表名1:a 表名2:b) &,zeBFmc
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^6'A
7、说明:在线视图查询(表名1:a ) $Tg$FfD6&
select * from (SELECT a,b,c FROM a) T where t.a > 1; C7#$s<>TO
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 U,'n}]=4A3
select * from table1 where time between time1 and time2 :&m(W Z\
select a,b,c, from table1 where a not between 数值1 and 数值2 #=rR[:M
9、说明:in 的使用方法 7F.,Xvw&@
select * from table1 where a [not] in ('值1','值2','值4','值6') art{PV4-
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /03>|Juo
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) r`2& o
11、说明:四表联查问题: (]:G"W8f
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 ..... F}Au'D&n_
12、说明:日程安排提前五分钟提醒 @lwqkJ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &+v&Dd&
13、说明:一条sql 语句搞定数据库分页 +-hmITJv
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 Fr~xN!
14、说明:前10条记录 e\<I:7%Rg
select top 10 * form table1 where 范围 ~J|0G6H
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.) V;"'!dVX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {8' 5
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 ' vwBG=9C
(select a from tableA ) except (select a from tableB) except (select a from tableC) 6{M.S}.^
17、说明:随机取出10条数据 iaB5t<t1r
select top 10 * from tablename order by newid() GOt@x9%
18、说明:随机选择记录 /?sV\shy
select newid() _3hEYeh
19、说明:删除重复记录 mIyaoIE|$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) F<$&G'% H
20、说明:列出数据库里所有的表名 am}zOr\
select name from sysobjects where type='U' F}X_I
21、说明:列出表里的所有的 >97N
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select name from syscolumns where id=object_id('TableName') =["GnL*!0
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。 [Mi~4b
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 { T.VB~C
显示结果: ?CIa)dhu
type vender pcs %9j]N$.V
电脑 A 1 C.@TX
电脑 A 1 G.Q+"+*^
光盘 B 2 8PQt8G.
光盘 A 2 M-NR!? 9
手机 B 3 jAu/]
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手机 C 3 c&Dy{B!
23、说明:初始化表table1 &b_duWs
TRUNCATE TABLE table1 "k.<" pf
24、说明:选择从10到15的记录 6vDgMfw
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E~B
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三、技巧 w^~,M3(+)1
1、1=1,1=2的使用,在SQL语句组合时用的较多 M<SZ7^9<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, q
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如: |
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if @strWhere !='' %lBFj/B
begin VD4(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere x-[l`k.V
end M-n +3E9
else s
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begin 0:XmReO+k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 6Pz\6DU,I
end d$!ibL#o
我们可以直接写成 y=t
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 8W{R&Z7aL
2、收缩数据库 &:rf80`z.
--重建索引 EB\\
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DBCC REINDEX R7#B_^ $
DBCC INDEXDEFRAG J&Ah52
--收缩数据和日志 $3So`8Bm[$
DBCC SHRINKDB ^Kn}{m/3Y
DBCC SHRINKFILE u!O)\m-
3、压缩数据库 +:b|I'S
dbcc shrinkdatabase(dbname) hGsYu )
4、转移数据库给新用户以已存在用户权限 },l3N K
exec sp_change_users_login 'update_one','newname','oldname' o!Y7y1$
go MD +Q_
5、检查备份集 V[~/sc )
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Lr`yl$6
6、修复数据库 w0pH|$"/P
ALTER DATABASE [dvbbs] SET SINGLE_USER B{44|aq1 |
GO d4lEd>Ni
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK N)QW$iw9
GO .mMM]*e[0
ALTER DATABASE [dvbbs] SET MULTI_USER Hg]r5Fe/c
GO !( /dbHB
7、日志清除 \Q]7Hw<
SET NOCOUNT ON ).\%a
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DECLARE @LogicalFileName sysname, `,J\E<4J
@MaxMinutes INT, L9T|* ?||
@NewSize INT u
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USE tablename -- 要操作的数据库名 Kg56.$
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 E;yP.<PW
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ig6F!p
@NewSize = 1 -- 你想设定的日志文件的大小(M) q:fkF^>
-- Setup / initialize 8q_nOGd
DECLARE @OriginalSize int yovC~
SELECT @OriginalSize = size 2TdcZ<k}J
FROM sysfiles cf96z|^C
WHERE name = @LogicalFileName d;K,2
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \]zHM.E1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + u-D%: lz85
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ay[6rUO
FROM sysfiles GujmBb
WHERE name = @LogicalFileName 'Je;3"@
CREATE TABLE DummyTrans 06ZyR@.@v
(DummyColumn char (8000) not null) XLB7
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DECLARE @Counter INT, )Zox;}WK+
@StartTime DATETIME, O9bIo]B
@TruncLog VARCHAR(255) kIyif7
SELECT @StartTime = GETDATE(), "5=Gu1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @I9A"4Im
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ->d3FR
EXEC (@TruncLog) 5-*/wKjLz
-- Wrap the log if necessary. q.*k
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _G@)Bj^*
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) [:Sl^ Z&6M
AND (@OriginalSize * 8 /1024) > @NewSize G22u+ua
BEGIN -- Outer loop. O.i.<VD7
SELECT @Counter = 0 C1hp2CW$5/
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) n}EH{k9#
BEGIN -- update NbH;@R)L
INSERT DummyTrans VALUES ('Fill Log') !IcPO
DELETE DummyTrans X-=49)
SELECT @Counter = @Counter + 1 fTMn
END K1Mn_)%
EXEC (@TruncLog) U 1vZr{\
END 12.|E d*72
SELECT 'Final Size of ' + db_name() + ' LOG is ' + U`z=!KI+g
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 05Ak[OOU>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' S3$&}I <
FROM sysfiles BKi@c\Wb
WHERE name = @LogicalFileName p[>!;qI
DROP TABLE DummyTrans }Ge$?ZFH
SET NOCOUNT OFF ^8OK.iC
8、说明:更改某个表 \Cx2$<8
exec sp_changeobjectowner 'tablename','dbo' vr"O9L
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9、存储更改全部表 PY[nnoF"|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ;ry~x:7L7
@OldOwner as NVARCHAR(128), Pd)mLs Jg
@NewOwner as NVARCHAR(128) @cukoLAn
AS ]V^ >aUlj
DECLARE @Name as NVARCHAR(128) 8u6*;*o
DECLARE @Owner as NVARCHAR(128) G0)}?5L1J
DECLARE @OwnerName as NVARCHAR(128) ;0FfP
DECLARE curObject CURSOR FOR 4}`z^P<C
select 'Name' = name, Qhy!:\&1
'Owner' = user_name(uid) 5<YV`T{5Kl
from sysobjects B 1jeIk,
where user_name(uid)=@OldOwner -%,=%FBi~4
order by name Q\rf J||
OPEN curObject _\;0E!=p
FETCH NEXT FROM curObject INTO @Name, @Owner a]]eQ(xQ
WHILE(@@FETCH_STATUS=0) 3?5JY;}h>"
BEGIN l|v`B6(
if @Owner=@OldOwner S"HdjEF7\
begin [>![ViX
set @OwnerName = @OldOwner + '.' + rtrim(@Name) lha)4d
exec sp_changeobjectowner @OwnerName, @NewOwner FJCs$0
end 7H.3.j(L
-- select @name,@NewOwner,@OldOwner H\RejGR
FETCH NEXT FROM curObject INTO @Name, @Owner Ym% XCl
END g-? @a
close curObject Ogv9_X8
deallocate curObject >e>%AMzo[
GO {>g{+Eq
10、SQL SERVER中直接循环写入数据 ia@ |+r
declare @i int $O3.ex V
set @i=1 gWQ(B
while @i<30 =U'!<w<-
begin 9k/L m
insert into test (userid) values(@i) z;DNl#|!L
set @i=@i+1 C cPOK2
end 9:R3+,ZN
小记存储过程中经常用到的本周,本月,本年函数 A*G ~#v^
Dateadd(wk,datediff(wk,0,getdate()),-1) ,<k%'a!B
Dateadd(wk,datediff(wk,0,getdate()),6) 1%ENgb:8
Dateadd(mm,datediff(mm,0,getdate()),0) L+N\B@ 0-
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) H-\Ym}BGu
Dateadd(yy,datediff(yy,0,getdate()),0) e.\dqt~%y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <p/zm}?')
上面的SQL代码只是一个时间段 bMn)lrsX
Dateadd(wk,datediff(wk,0,getdate()),-1) -U*J5Q
Dateadd(wk,datediff(wk,0,getdate()),6) SSxp!E'
就是表示本周时间段. ,.Lwtp,n
下面的SQL的条件部分,就是查询时间段在本周范围内的: DSQ2|{
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9TX2h0U?
而在存储过程中 +-C.E
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) bgLa`8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4O<sE@X