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。 B5$kHM%p
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一、基础 T1H"\+
1、说明:创建数据库 OrK&RC
CREATE DATABASE database-name P9 Z}H(?C
2、说明:删除数据库 7B?c{
drop database dbname Pi|o` d
3、说明:备份sql server =9T$Gr
--- 创建 备份数据的 device G z)NwD
USE master Po%(~ )S>
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Dl}$pN
--- 开始 备份 jmeRrnC}
BACKUP DATABASE pubs TO testBack &iV{:)L
4、说明:创建新表 dUsxvho
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h yv2SxP*
根据已有的表创建新表: %Rsp;1Z
A:create table tab_new like tab_old (使用旧表创建新表) A<ynIs<
B:create table tab_new as select col1,col2... from tab_old definition only G$sA`<<
5、说明:删除新表 71l%MH
drop table tabname %.vVEy
6、说明:增加一个列 +]Y,q
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Alter table tabname add column col type Tyck/ EO
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。 $kQ~d8 O
7、说明:添加主键: Alter table tabname add primary key(col) fDP$ sW
说明:删除主键: Alter table tabname drop primary key(col) nl9P,
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8、说明:创建索引:create [unique] index idxname on tabname(col....) HJY2#lSha6
删除索引:drop index idxname :<|<|qJWo
注:索引是不可更改的,想更改必须删除重新建。 `He,p -
9、说明:创建视图:create view viewname as select statement 1x,tu}<u^
删除视图:drop view viewname 3'X.}>o
10、说明:几个简单的基本的sql语句 (P`3 @H
选择:select * from table1 where 范围 /soKucN"h
插入:insert into table1(field1,field2) values(value1,value2) +$Rt+S BD
删除:delete from table1 where 范围 I"`M@ %
更新:update table1 set field1=value1 where 范围 9VbOQ {8
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {`w;39$+
排序:select * from table1 order by field1,field2 [desc] wm^J;<T[
总数:select count as totalcount from table1 .rf"
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求和:select sum(field1) as sumvalue from table1 L{c q, jk
平均:select avg(field1) as avgvalue from table1 ZIF49`Y4TF
最大:select max(field1) as maxvalue from table1 }[xs~!2F
最小:select min(field1) as minvalue from table1 <'g:T(t
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11、说明:几个高级查询运算词 oqeSG.1
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A: UNION 运算符 &
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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。 M8TSt\
B: EXCEPT 运算符 ?y!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。 $r3i2N-I
C: INTERSECT 运算符 F_4n^@M
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ^53r/V }%
注:使用运算词的几个查询结果行必须是一致的。 9 '2_
12、说明:使用外连接 ERN>don2
A、left outer join: !e?.6% %
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 7t*"%]o
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ZGd!IghL
B:right outer join: &%/7E_j7
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 fS`$'BQ
C:full outer join: 42qYg(tZ
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。 'R:"5d
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二、提升 2J;kSh1,L
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) M^]cM(swK5
法一:select * into b from a where 1<>1 J.|+ID+
法二:select top 0 * into b from a =3v]gOcO
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _x5 3g
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insert into b(a, b, c) select d,e,f from b; %?Ev|:i`@
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) ~T89_L
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mN19WQ(r
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 6!(@@^7{*
4、说明:子查询(表名1:a 表名2:b) Q0ON9gqqv
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) \0gM o&
5、说明:显示文章、提交人和最后回复时间 (zFi$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Qg<(u?7N
6、说明:外连接查询(表名1:a 表名2:b) 1&U>,;]*
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c IOV(seEY
7、说明:在线视图查询(表名1:a ) ]S5JUAGkE*
select * from (SELECT a,b,c FROM a) T where t.a > 1; y?q*WUh
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 g"> {9YE
select * from table1 where time between time1 and time2 PKzyV ;
select a,b,c, from table1 where a not between 数值1 and 数值2 *VZ5B<Ic
9、说明:in 的使用方法 W}]%X4<#rN
select * from table1 where a [not] in ('值1','值2','值4','值6') TU
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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 1N>|yQz
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) wg]j+r@
11、说明:四表联查问题: \R;`zuv
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 ..... 6}oXP_0U
12、说明:日程安排提前五分钟提醒 QD>"]ap,o
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4tS.G
13、说明:一条sql 语句搞定数据库分页 E}tqQ*u
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 '>rw(3
14、说明:前10条记录 q+vx_4
select top 10 * form table1 where 范围 I=NZokfS
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.) xcf%KXJf6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Bb"Bg\le,^
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 [ra_ 2R
(select a from tableA ) except (select a from tableB) except (select a from tableC) G-.^O,%
17、说明:随机取出10条数据 A,LuD.8
select top 10 * from tablename order by newid() i?F
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18、说明:随机选择记录 v3jg~"!
select newid() $"H{4x`-
19、说明:删除重复记录 E 0?iXSJ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ])!o5`ltZ
20、说明:列出数据库里所有的表名 a0ObBe'
select name from sysobjects where type='U' ;{"+g)u
21、说明:列出表里的所有的 81i655!Z
select name from syscolumns where id=object_id('TableName') L#
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 "
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type w2'f/
显示结果: pn5Q5xc
type vender pcs hBX!iukT|{
电脑 A 1 LmnymcH
电脑 A 1 <fFTY130:
光盘 B 2 dp*u9z~NA
光盘 A 2 F;<xnC{[
手机 B 3 CLJ;<
手机 C 3 TBT:/Vfun
23、说明:初始化表table1 <h'5cO
TRUNCATE TABLE table1 oT>(V]*5
24、说明:选择从10到15的记录 Yn G_m]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2mGaD\?K
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三、技巧 p ObX42
1、1=1,1=2的使用,在SQL语句组合时用的较多 !GNBDRr
"where 1=1" 是表示选择全部 "where 1=2"全部不选, EG=Sl~~o
如: Aw5HF34J
if @strWhere !='' {>)#HD
begin G8Y<1%`<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere % V8U(z
end #Ibp(
else ?pB>0b~3-
begin d*%`!G
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Evjj"h&0J
end 7G>dTO
我们可以直接写成 Q{5kxw1ZF
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 3skC$mpJHw
2、收缩数据库 ,~]tg77
--重建索引 %s(k_|G+4
DBCC REINDEX "pRtczxOgR
DBCC INDEXDEFRAG b7p@Dn?E
--收缩数据和日志 aD$v2)RR
DBCC SHRINKDB S_IUV)
DBCC SHRINKFILE D,k"PaLP
3、压缩数据库 Y/ .Z.FD`
dbcc shrinkdatabase(dbname) Us0EG\Y
4、转移数据库给新用户以已存在用户权限 Z
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exec sp_change_users_login 'update_one','newname','oldname' ]33>m|?@
go K8UP,f2
5、检查备份集 %*0^0wz
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 8Y7Q+p|O
6、修复数据库 >^*+iEe
ALTER DATABASE [dvbbs] SET SINGLE_USER M 4?ig}kh
GO W)f/0QX}W
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @3C>BLI8+
GO k@3Q|na
ALTER DATABASE [dvbbs] SET MULTI_USER 283F)T\Rv
GO s pp f
7、日志清除 ~2QR{; XQ
SET NOCOUNT ON N%*5 T[.
DECLARE @LogicalFileName sysname, j+uLV{~g6
@MaxMinutes INT, P<a)25be/
@NewSize INT 'g
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USE tablename -- 要操作的数据库名 /! "|_W|n
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "Pu!dJ5[]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. f>UXD
@NewSize = 1 -- 你想设定的日志文件的大小(M) E(8*
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-- Setup / initialize m;GbLncA
DECLARE @OriginalSize int 8)10o,#L
SELECT @OriginalSize = size rFj-kojg
FROM sysfiles vPTM
WHERE name = @LogicalFileName |w<H!lGe!$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2;DuHO1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + D)m5
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' M$>1L
FROM sysfiles UVd 7 JGR
WHERE name = @LogicalFileName U<_3^
CREATE TABLE DummyTrans =pS5uR~
(DummyColumn char (8000) not null) fj;y}t1E]
DECLARE @Counter INT, n O\"HLM
@StartTime DATETIME, 0dGAP
@TruncLog VARCHAR(255) e'~J,(fB
SELECT @StartTime = GETDATE(), 5?3Me59
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' b2OQtSr a
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =IQ5<;U3
EXEC (@TruncLog) #AL=f'2=f
-- Wrap the log if necessary. DkvF 5c&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired W"}M1o
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~nh:s|l6%M
AND (@OriginalSize * 8 /1024) > @NewSize pxCK;]
BEGIN -- Outer loop. S/e2P|}
SELECT @Counter = 0 C8 xZ;V]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) pu
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BEGIN -- update 0;AA/
INSERT DummyTrans VALUES ('Fill Log') ?&63#B,iZ
DELETE DummyTrans /tf5Bv'<
SELECT @Counter = @Counter + 1 !O:y@
END y}My.c
EXEC (@TruncLog) 8o'_`{ba
END :+z4~%
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + "AnC?c9?-^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ujR_"r|l
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' JNt^ (z
FROM sysfiles r0+6evU2
WHERE name = @LogicalFileName 6/r)y+H
DROP TABLE DummyTrans +#lM
SET NOCOUNT OFF ^h~x)@=
8、说明:更改某个表 pgE}NlW
exec sp_changeobjectowner 'tablename','dbo' v*SEb~[
9、存储更改全部表 LSGBq
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch B&[M7i
@OldOwner as NVARCHAR(128), W;'!gpa
@NewOwner as NVARCHAR(128) VcSVu
AS \KQ71yqY
DECLARE @Name as NVARCHAR(128) +zaA,e?\
DECLARE @Owner as NVARCHAR(128) 5qZ1FE
DECLARE @OwnerName as NVARCHAR(128) =/y]d<g
DECLARE curObject CURSOR FOR a1+#3X.
select 'Name' = name, X[PZg{
'Owner' = user_name(uid) 2[RoxKm
from sysobjects %.^_Ps0
where user_name(uid)=@OldOwner T_@K&<
order by name @` 1Ds
OPEN curObject *E/`KUG]
FETCH NEXT FROM curObject INTO @Name, @Owner |
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WHILE(@@FETCH_STATUS=0) T`\x,`
^
BEGIN t>urc
if @Owner=@OldOwner :U3kW8;UMP
begin qln3 k`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) |"/8XA
exec sp_changeobjectowner @OwnerName, @NewOwner %_RQx2
end D#il*
-- select @name,@NewOwner,@OldOwner /H(?
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FETCH NEXT FROM curObject INTO @Name, @Owner cDFO; Dr
END %)|9E>fP]N
close curObject 52 fA/sx
deallocate curObject Crho=RJPR
GO %|g>%D3Z?
10、SQL SERVER中直接循环写入数据 TDFkxB>
declare @i int #LL?IRH9^
set @i=1 zF8dKFE~
while @i<30 :Q $K<)[
begin 7VqM$I
insert into test (userid) values(@i) /%}*Xh
set @i=@i+1 +e yc`J
end nrxo&9[@n
小记存储过程中经常用到的本周,本月,本年函数 `\gnl'
Dateadd(wk,datediff(wk,0,getdate()),-1) E*V`":efS
Dateadd(wk,datediff(wk,0,getdate()),6) [E!oQVY
Dateadd(mm,datediff(mm,0,getdate()),0) aE&,]'6
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) m#PY,y
Dateadd(yy,datediff(yy,0,getdate()),0) aqRhh=iS
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2Ga7$q
上面的SQL代码只是一个时间段 =BSzsH7
Dateadd(wk,datediff(wk,0,getdate()),-1) wKZ$iGMbz
Dateadd(wk,datediff(wk,0,getdate()),6) `\T]ej}zvI
就是表示本周时间段. \>:CvTzF
下面的SQL的条件部分,就是查询时间段在本周范围内的: x(etb<!jd
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) #{?PbBE}
而在存储过程中 P9^-6;'Y
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) trPAYa}W
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) FbaEB RM