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。 7 G[ GHc>
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一、基础 #/t>}lc
1、说明:创建数据库 (U'7Fc
CREATE DATABASE database-name z]l-?>Zbg
2、说明:删除数据库 V87ee,
drop database dbname i %hn
3、说明:备份sql server y'!p>/%v
--- 创建 备份数据的 device Ot$cmBhw!
USE master r(1pvcWY-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 3cfZ!E~^kc
--- 开始 备份 CESe}^)n
BACKUP DATABASE pubs TO testBack ).+xcv
4、说明:创建新表 t7oz9fSz=?
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) rfXF 01I
根据已有的表创建新表: 9[p}.9/
A:create table tab_new like tab_old (使用旧表创建新表) ~I\r1Wj;
B:create table tab_new as select col1,col2... from tab_old definition only O3C)N
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5、说明:删除新表 _"!{7e`Z
drop table tabname |t 65#1
6、说明:增加一个列 Gj7QGIKx
Alter table tabname add column col type =*:[(Py1
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 W|H4i;u
7、说明:添加主键: Alter table tabname add primary key(col) s/G5wRl<
说明:删除主键: Alter table tabname drop primary key(col) {`K]sa7`
8、说明:创建索引:create [unique] index idxname on tabname(col....) [wy3Ld
删除索引:drop index idxname S?nNZW\6[
注:索引是不可更改的,想更改必须删除重新建。 Tc3ih~LvG
9、说明:创建视图:create view viewname as select statement z<[.MH`ln
删除视图:drop view viewname <S8I"8{Mb
10、说明:几个简单的基本的sql语句 *M5$ h*;v
选择:select * from table1 where 范围 2>MP:yY;K
插入:insert into table1(field1,field2) values(value1,value2) Eo {1y
删除:delete from table1 where 范围 XuFm4DEJ
更新:update table1 set field1=value1 where 范围 }U?gKlLg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! p21=$?k!;
排序:select * from table1 order by field1,field2 [desc] @%G' U&R{
总数:select count as totalcount from table1 D2TXOPH
求和:select sum(field1) as sumvalue from table1 SJ@8[n.x
平均:select avg(field1) as avgvalue from table1 7:VEM;[d
最大:select max(field1) as maxvalue from table1 Xw*%3'
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 ^C:{z)"h
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A: UNION 运算符 ]*g ss'N
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。 A|
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B: EXCEPT 运算符 Nn,vdu{^2
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。 K{=r.W
C: INTERSECT 运算符 U5On-T5
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。 s]F?=yEp
注:使用运算词的几个查询结果行必须是一致的。 5S|}:~7T
12、说明:使用外连接 (b`4&sQ<
A、left outer join: ]} 5I>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。 ++T
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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 q#Yg0w~
B:right outer join: H;TOPtt2
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。 33{;[/4
C:full outer join: VGTeuu5i
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。 HC9vc,Fp
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二、提升 k Z+ q
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 45r]wT(C
法一:select * into b from a where 1<>1 vu_>U({.
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法二:select top 0 * into b from a Xa{~a3Wy
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =9DhO7I'
insert into b(a, b, c) select d,e,f from b; v|4STR
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) nxn[ ~~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?8wwd!)x%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Q8;x9o@p
4、说明:子查询(表名1:a 表名2:b)
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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) 'uP'P#
5、说明:显示文章、提交人和最后回复时间 (opROsFh
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .KiPNTh'
6、说明:外连接查询(表名1:a 表名2:b) z&C{8aQ'
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -(/2_&"
7、说明:在线视图查询(表名1:a ) 3D?IG\3
select * from (SELECT a,b,c FROM a) T where t.a > 1; c]s(u+i
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 c ,h.`~{
select * from table1 where time between time1 and time2 eEW roF
select a,b,c, from table1 where a not between 数值1 and 数值2 r%g
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9、说明:in 的使用方法 E(aX4^]g
select * from table1 where a [not] in ('值1','值2','值4','值6') =1{H
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 7X9+Qj;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $I)Tk`=
11、说明:四表联查问题: YiIddQ
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 ..... sW]yuu!/
12、说明:日程安排提前五分钟提醒 %Lh-aP{[e
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wE,=%?"
13、说明:一条sql 语句搞定数据库分页 I<D&,LFH*w
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 2cs?("8e%
14、说明:前10条记录 aJK-O"0/
select top 10 * form table1 where 范围 S 0R8'Y
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.) ys&"r":I
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) g^s+C Z
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 wq:b j=j
(select a from tableA ) except (select a from tableB) except (select a from tableC) 7.7Cluh5,
17、说明:随机取出10条数据 ['51FulDR
select top 10 * from tablename order by newid() K:>NGGY8r
18、说明:随机选择记录 L<f-Ed9|
select newid() tl{]gz
19、说明:删除重复记录 ')AByD}Hi]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _%A/ )
20、说明:列出数据库里所有的表名 '\ph`Run
select name from sysobjects where type='U' l1-4n*fU
21、说明:列出表里的所有的 -vv
select name from syscolumns where id=object_id('TableName') $:%*gY4~76
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。 5z9r S<
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!m42EvIvE
显示结果: $\0cJCQ3
type vender pcs ~I8v5 H
电脑 A 1 +?URVp
电脑 A 1 ,X9hl J
光盘 B 2 ;eS;AHZ
光盘 A 2 k1^V?O
手机 B 3 S`pF7[%rp
手机 C 3 XsAY4WTS
23、说明:初始化表table1 L"""\5Bn(
TRUNCATE TABLE table1 gZw\*9Q9
24、说明:选择从10到15的记录 SjZd0H0
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 3gxf~$)?
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三、技巧 ~fyF&+ibp'
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]}nu9z<
"where 1=1" 是表示选择全部 "where 1=2"全部不选, v
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如: EHH|4;P6
if @strWhere !='' :@:g*w2K
begin r :fwrC
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere H/cs_i
end UlK/x"JDv
else b*lKT]D,
begin C$KaT3I
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' N+*(Y5TU
end G[|3^O>P
我们可以直接写成 =ied}a
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere aj&\CJ
2、收缩数据库 kA1RfSS
--重建索引 pWMiCXnW
DBCC REINDEX h=X7,2/<
DBCC INDEXDEFRAG 5T!&r
--收缩数据和日志 cj$,ob&DX
DBCC SHRINKDB -0A@38, }
DBCC SHRINKFILE Y Eg
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3、压缩数据库 6tOP}X
dbcc shrinkdatabase(dbname) "AT&!t[J
4、转移数据库给新用户以已存在用户权限 y.jS{r".
exec sp_change_users_login 'update_one','newname','oldname' 5\uNEs$T
go Q<z)q<e
5、检查备份集 FpP\-+Sl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ,)Yao;Cvd
6、修复数据库 5?^]1P_
ALTER DATABASE [dvbbs] SET SINGLE_USER MNkKy(Za
GO '"Bex`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO
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ALTER DATABASE [dvbbs] SET MULTI_USER }phz7N9
GO 'g. :MQ8
7、日志清除 8r2XGR
SET NOCOUNT ON ,yTN$K%M
DECLARE @LogicalFileName sysname, {\P?/U6~f
@MaxMinutes INT, w+Ad$4Pf"
@NewSize INT G"}qV%"6"
USE tablename -- 要操作的数据库名 -s{R/ 6:
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [Dnusp7e
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (&q@~
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@NewSize = 1 -- 你想设定的日志文件的大小(M) aLV~|$:2
-- Setup / initialize [fd~nD#.
DECLARE @OriginalSize int %rFP#L
SELECT @OriginalSize = size }%_qx|(P|t
FROM sysfiles .8-PB*vb
WHERE name = @LogicalFileName )8:n}w
SELECT 'Original Size of ' + db_name() + ' LOG is ' + K3Huu!Tr
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [0K=I64
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1Pu
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FROM sysfiles Q?Wr7
WHERE name = @LogicalFileName OdO{xG G@
CREATE TABLE DummyTrans {PL,VY)Z
(DummyColumn char (8000) not null) baqn7k"
DECLARE @Counter INT, 7^HpVcSM
@StartTime DATETIME, "_t4F4z
@TruncLog VARCHAR(255) X88F>1}
SELECT @StartTime = GETDATE(), 8a7YHUL<3i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) [70Y,,w
EXEC (@TruncLog) Mk<m6E$L
-- Wrap the log if necessary. IT,"8s
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired FSv1X
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) cS4xe(n8
AND (@OriginalSize * 8 /1024) > @NewSize
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BEGIN -- Outer loop. nZe\5`
SELECT @Counter = 0 AmZuo_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) I`lDWL
BEGIN -- update [S%J*sz~
INSERT DummyTrans VALUES ('Fill Log') P1$f}K}
DELETE DummyTrans M\I_{Q?_
SELECT @Counter = @Counter + 1 xOhRTxic
END e!6eZ)l
EXEC (@TruncLog) ubD#I{~J
END OO$|9`a
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ACgt"
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 61G|?Aax
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -H4PRCDH
FROM sysfiles {d8^@UL
WHERE name = @LogicalFileName k@7kNMl
DROP TABLE DummyTrans {K+.A 9!
SET NOCOUNT OFF se!g4XEWD
8、说明:更改某个表 )ukF3;Gt
exec sp_changeobjectowner 'tablename','dbo' rYbCOazr
9、存储更改全部表 *jGPGnSo
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch (yfXMp,x
@OldOwner as NVARCHAR(128), %t q&
@NewOwner as NVARCHAR(128) Kf|0*c
AS P7'M],!9w
DECLARE @Name as NVARCHAR(128) '\@WN]
DECLARE @Owner as NVARCHAR(128) )4PB<[u
DECLARE @OwnerName as NVARCHAR(128) |%-YuD
DECLARE curObject CURSOR FOR O
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select 'Name' = name, 2f `&WUe
'Owner' = user_name(uid) QJQJR/g
from sysobjects D_Guc8*
where user_name(uid)=@OldOwner >cTjA):
order by name @$Yb#$/
OPEN curObject rj}(muM,R
FETCH NEXT FROM curObject INTO @Name, @Owner Mg+4huT
WHILE(@@FETCH_STATUS=0) -gB{:UYi3
BEGIN [~t yDLC
if @Owner=@OldOwner !W(`<d]68:
begin lelMt=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) a`s/ qi
exec sp_changeobjectowner @OwnerName, @NewOwner =ydpU<aS
end <W?WUF
-- select @name,@NewOwner,@OldOwner ssPI$IRg!
FETCH NEXT FROM curObject INTO @Name, @Owner &h\7^=s.
END _OLI%o
close curObject 'g2vX&=$A
deallocate curObject s_TD4~
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GO 9+t=|
10、SQL SERVER中直接循环写入数据
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declare @i int (N7O+3+G
set @i=1 ve6x/ PD
while @i<30 \,hrk~4U;(
begin #.o0mguU
insert into test (userid) values(@i) 4Q$!c{Y
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set @i=@i+1 h+5@I%WX
end LGAX"/LX
小记存储过程中经常用到的本周,本月,本年函数 pG~'shD~Dn
Dateadd(wk,datediff(wk,0,getdate()),-1) .ByU
Dateadd(wk,datediff(wk,0,getdate()),6) @\!ww/QT
Dateadd(mm,datediff(mm,0,getdate()),0) (xbIUz.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) db'K!M)
Dateadd(yy,datediff(yy,0,getdate()),0) IEc>.J|T&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4aA9\\hfGY
上面的SQL代码只是一个时间段 *N`;I@Q"[
Dateadd(wk,datediff(wk,0,getdate()),-1) Wy8,<K{
Dateadd(wk,datediff(wk,0,getdate()),6) 1c/
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就是表示本周时间段. p+vh[+yp
下面的SQL的条件部分,就是查询时间段在本周范围内的: C>NQ-w^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) RNvQ
而在存储过程中 D@:"f?K>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) j!7Qw 8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ZRPE-l_3: