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。 s?E: ]
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一、基础 ckk [n
1、说明:创建数据库 {EUH#':
CREATE DATABASE database-name ;R!H\
2、说明:删除数据库 %E\%nTV
drop database dbname .'1j5Y-l`N
3、说明:备份sql server \d+HYLAJn
--- 创建 备份数据的 device \PONaRK|[z
USE master gNd
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 20qVzXi
--- 开始 备份 ]EnaZWyO]
BACKUP DATABASE pubs TO testBack 0)]1)z(P
4、说明:创建新表 j#f&!&G5<&
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ,]mwk~HeF
根据已有的表创建新表: %}!}2s.A
A:create table tab_new like tab_old (使用旧表创建新表) srLr~^$j[
B:create table tab_new as select col1,col2... from tab_old definition only /8>/"Z2S
5、说明:删除新表 U08?*{
drop table tabname n y)P
6、说明:增加一个列 0AKwZ'
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Alter table tabname add column col type
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注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ELF`uWGE
7、说明:添加主键: Alter table tabname add primary key(col) ..!-)q'?
说明:删除主键: Alter table tabname drop primary key(col) L"I] mQvd
8、说明:创建索引:create [unique] index idxname on tabname(col....) 8$kXC+
删除索引:drop index idxname }GDG$QI]K&
注:索引是不可更改的,想更改必须删除重新建。 b
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9、说明:创建视图:create view viewname as select statement Y0\\(0j64
删除视图:drop view viewname k)V%.Eobf
10、说明:几个简单的基本的sql语句 Sp,Q,Q4
选择:select * from table1 where 范围 @a\SR'8
插入:insert into table1(field1,field2) values(value1,value2) M%s$F@
删除:delete from table1 where 范围 oB
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更新:update table1 set field1=value1 where 范围 )K>@$6H+2
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D(6x'</>?
排序:select * from table1 order by field1,field2 [desc] "q^'5p]
总数:select count as totalcount from table1 _|B&v
求和:select sum(field1) as sumvalue from table1 !muYn-4M
平均:select avg(field1) as avgvalue from table1 9[{>JRm.
最大:select max(field1) as maxvalue from table1 K]!u@I* K"
最小:select min(field1) as minvalue from table1 d5"EvT
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11、说明:几个高级查询运算词 u?;Vxh3@|
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A: UNION 运算符 hdtnC29$
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。 ;c-
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B: EXCEPT 运算符 NS4'IR=;E!
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。 T#G<?oF
C: INTERSECT 运算符 rk,1am:cg
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。 V<2fPDZ
注:使用运算词的几个查询结果行必须是一致的。 j'Y"/<
12、说明:使用外连接 %y\eBfW,/
A、left outer join: qD;v/,?
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。 :~3{oZGX&
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 mH*@d"
B:right outer join: 0\Yx.\X,
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。 L;M^>{>
C:full outer join:
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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。 i<wU.JX&h
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二、提升 ]\RSHz
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )'!ml
法一:select * into b from a where 1<>1 5+bFy.UW
法二:select top 0 * into b from a df>kEvU5.^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) e-iYJ?
insert into b(a, b, c) select d,e,f from b; 1rv$?=Z
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Xvu)
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 &7($kj
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "VDk1YX_&l
4、说明:子查询(表名1:a 表名2:b) VPM|Rj:d
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) AGEZ8(h
5、说明:显示文章、提交人和最后回复时间 QP$nDK<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b pfL2v,]g
6、说明:外连接查询(表名1:a 表名2:b) ]M~8@K
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3V/_I<y
7、说明:在线视图查询(表名1:a ) Yz2{LW[K
select * from (SELECT a,b,c FROM a) T where t.a > 1; m)@Q_{=6M
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 K}PvrcO1
select * from table1 where time between time1 and time2 9V=<| 2
select a,b,c, from table1 where a not between 数值1 and 数值2 m|[\F#+C
9、说明:in 的使用方法 p;qRm}
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select * from table1 where a [not] in ('值1','值2','值4','值6') (Bt;DM#>
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
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) GB<R7J
11、说明:四表联查问题: }c`
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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 ..... 5ys#L&q'Z
12、说明:日程安排提前五分钟提醒 N<aB)</
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7.Ml9{M/i
13、说明:一条sql 语句搞定数据库分页 pXPqDA
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 ?CH?kP
14、说明:前10条记录 E\R raPkQT
select top 10 * form table1 where 范围 _kn]#^ucCe
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.) c8#T:HM|`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "H5&3sF2
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 n 5~=qQK2
(select a from tableA ) except (select a from tableB) except (select a from tableC) F~z_>1lpP&
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() x1Nme%%&
18、说明:随机选择记录 kF+ZW%6N
select newid() <TI3@9\qXE
19、说明:删除重复记录 E7rX1YdR
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) C!!mOAhJ
20、说明:列出数据库里所有的表名 CxJfrI_W
select name from sysobjects where type='U' ,3:QB_
21、说明:列出表里的所有的 0fnZR$PB
select name from syscolumns where id=object_id('TableName') |yLk5e~@-
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。 g9DG=\*A
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 5{')GTdX>
显示结果: TT|-aS0l(u
type vender pcs ;e&!
电脑 A 1 d4ic9u*D
电脑 A 1 -&trk
光盘 B 2 3QCMK^#Z:
光盘 A 2 pz$_W
手机 B 3 ER{yuw
手机 C 3 hgj CXl
23、说明:初始化表table1 DXKyRkn6e
TRUNCATE TABLE table1
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24、说明:选择从10到15的记录 c2/FHI0J;
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc )j\r,9<K+5
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三、技巧 ]yo_wGiwY
1、1=1,1=2的使用,在SQL语句组合时用的较多 pw!@Q?R
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #De(*&y2
如: bpGzTU
if @strWhere !='' b<\$d4Qy
begin Bk+{}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1sD~7KPg?
end -=}b;Kf-
else 0X.TF
begin C+`xx('N9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' EVG"._I@
end gTnS[
我们可以直接写成 N9pwWg&<+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Bn{)|&;
2、收缩数据库 sqT^t!
--重建索引 )R~a;?T_c0
DBCC REINDEX MZ)T0|S_
DBCC INDEXDEFRAG M=W
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--收缩数据和日志 q=njKC
DBCC SHRINKDB goB;EWz
DBCC SHRINKFILE {b2 aL7
3、压缩数据库 7g5@vYS+
dbcc shrinkdatabase(dbname) oQ{cSThj
4、转移数据库给新用户以已存在用户权限 q4)Ey
exec sp_change_users_login 'update_one','newname','oldname' X3AwM%,!
go Gh'X.?3
5、检查备份集 %0lf
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vffH
6、修复数据库 [NL -!
ALTER DATABASE [dvbbs] SET SINGLE_USER kB
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GO J)#S-ZB+'k
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o ~;M"
GO \KCWYi]
ALTER DATABASE [dvbbs] SET MULTI_USER bfhz?,b
GO 7u|%^Ao6
7、日志清除 Si]X
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SET NOCOUNT ON ^(DL+r,
DECLARE @LogicalFileName sysname, aV#h5s
@MaxMinutes INT, Ts#pUoE~+H
@NewSize INT Gp8psH
USE tablename -- 要操作的数据库名 i+I0k~wY
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 .+HcA x{/2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 12 -EDg/1
@NewSize = 1 -- 你想设定的日志文件的大小(M) :WO{x g
-- Setup / initialize q=+wI"[
DECLARE @OriginalSize int zC#%6@P\
SELECT @OriginalSize = size \OT6L'l],
FROM sysfiles WU7cF81$
WHERE name = @LogicalFileName @%:E }
SELECT 'Original Size of ' + db_name() + ' LOG is ' + oBC]UL;8xJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + #n#HzbT
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *x!LKIpv
FROM sysfiles Zt_r9xs>
WHERE name = @LogicalFileName 3Soy3Xp
CREATE TABLE DummyTrans m
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(DummyColumn char (8000) not null) ~U3Seo }
DECLARE @Counter INT, HD H
@StartTime DATETIME, }2=hd. .
@TruncLog VARCHAR(255) +!><5
SELECT @StartTime = GETDATE(), 5D
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ~?d>fR:X
DBCC SHRINKFILE (@LogicalFileName, @NewSize) '-.wFB;
EXEC (@TruncLog) ?M~
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-- Wrap the log if necessary. 1fR P1
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired w&5/Zh[~~L
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) q~M2:SN@X
AND (@OriginalSize * 8 /1024) > @NewSize +|0 t
BEGIN -- Outer loop. O+b6lg)q
SELECT @Counter = 0 dXK-&Po'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &oEyixe
BEGIN -- update |EEi&GOR(y
INSERT DummyTrans VALUES ('Fill Log') wV>c" J
DELETE DummyTrans 7f
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SELECT @Counter = @Counter + 1 -yl;3K]l
END z37Z%^
EXEC (@TruncLog) G1[(F`t>
END 59Nd}wPO;
SELECT 'Final Size of ' + db_name() + ' LOG is ' + M $uf:+F
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + LQ>$>A(
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xl,ryc3J
FROM sysfiles [<S^c[47U
WHERE name = @LogicalFileName 5k~\or 5_
DROP TABLE DummyTrans !-,Ww[G>
SET NOCOUNT OFF ?BsH{QRYQ
8、说明:更改某个表 4 4`WYK l
exec sp_changeobjectowner 'tablename','dbo' b5S7{"<V
9、存储更改全部表 z7k$0&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch AqqHD=Yp
@OldOwner as NVARCHAR(128), &mdB\Y?^
@NewOwner as NVARCHAR(128) [xf$VkjuF
AS lRH0)5`
DECLARE @Name as NVARCHAR(128) `x2,;h!:)N
DECLARE @Owner as NVARCHAR(128) I&\4C.\>
DECLARE @OwnerName as NVARCHAR(128) 3.FR C
DECLARE curObject CURSOR FOR p&O8qAaO
select 'Name' = name, DJ|BM+
'Owner' = user_name(uid) #D0W7a
from sysobjects PkO!'X
where user_name(uid)=@OldOwner mw"}8y
order by name Xb0!( (A
OPEN curObject A_i zSzC1
FETCH NEXT FROM curObject INTO @Name, @Owner 5{>>,pP&
WHILE(@@FETCH_STATUS=0) =]d^3bqN
BEGIN +`Fb_m)f
if @Owner=@OldOwner 2qXo{C3
begin D:)~%wu Lt
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Bj8<@~bX:L
exec sp_changeobjectowner @OwnerName, @NewOwner "/!'9na{QL
end :cdQ(O.m
-- select @name,@NewOwner,@OldOwner sJv`fjf%8
FETCH NEXT FROM curObject INTO @Name, @Owner ZMJ3NN]F
END 4i`S+`#
close curObject yf?W^{^|
deallocate curObject k% NrL@z
GO Pt(tRH B
10、SQL SERVER中直接循环写入数据 ]zcV]Qj$~
declare @i int %Co
b(C&}
set @i=1 w?S8@|MK
while @i<30 #@E(<Pu4`
begin zWtj|%ts
insert into test (userid) values(@i) PF67z]<o
set @i=@i+1 .*:h9AE7vo
end p7$3`t6u
小记存储过程中经常用到的本周,本月,本年函数 Yw1Y-M
Dateadd(wk,datediff(wk,0,getdate()),-1) CC>($k"
Dateadd(wk,datediff(wk,0,getdate()),6) A6Q c;v+
Dateadd(mm,datediff(mm,0,getdate()),0) V(DjF=8
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) j3LNnZY
Dateadd(yy,datediff(yy,0,getdate()),0) [WYJrk.
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) RPY6Wh|4
上面的SQL代码只是一个时间段 %]!?{U\*k
Dateadd(wk,datediff(wk,0,getdate()),-1) DP0Z*8Ia
Dateadd(wk,datediff(wk,0,getdate()),6) M&OsRrq
就是表示本周时间段. `BpCRKTG
下面的SQL的条件部分,就是查询时间段在本周范围内的: m
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %uW<
而在存储过程中 418gcg6)
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) E}t-N
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =uS8>.Qj