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。 >R?EJ;h
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一、基础 d8g3hyI5\
1、说明:创建数据库 Q=yQEh|Y
CREATE DATABASE database-name \PzC:H
2、说明:删除数据库 !&C8y
drop database dbname oJ`ih&Q8
3、说明:备份sql server F'Fc)9qFa<
--- 创建 备份数据的 device WjGv%^?
USE master J%xp1/=2
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' sm}v0V.Js
--- 开始 备份 M6!kn~
BACKUP DATABASE pubs TO testBack ~aH*ZA*f
4、说明:创建新表
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) qkv.,z"
根据已有的表创建新表: J=TbZL4y}4
A:create table tab_new like tab_old (使用旧表创建新表) )^)V yI`O
B:create table tab_new as select col1,col2... from tab_old definition only r3w. $
5、说明:删除新表 5SX0g(C
drop table tabname ,u(g#T
6、说明:增加一个列 u *z $ I
Alter table tabname add column col type 1z~;c|
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。 @l&5 |Cia
7、说明:添加主键: Alter table tabname add primary key(col) 6.~(oepu
说明:删除主键: Alter table tabname drop primary key(col) P]+^^U
8、说明:创建索引:create [unique] index idxname on tabname(col....) Tp<=dH%$%"
删除索引:drop index idxname ]k{cPK
注:索引是不可更改的,想更改必须删除重新建。 ZzI^*Nyg
9、说明:创建视图:create view viewname as select statement ;4F[*VF!w
删除视图:drop view viewname S'Q$N-Dy
10、说明:几个简单的基本的sql语句 Bw"L!sZ
选择:select * from table1 where 范围 !cnH|ePbI
插入:insert into table1(field1,field2) values(value1,value2) ~SZ0Yu:X
删除:delete from table1 where 范围 n <lU;
更新:update table1 set field1=value1 where 范围 wH!]B-hn
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! N{P (ym2yR
排序:select * from table1 order by field1,field2 [desc] 1_/\{quE
总数:select count as totalcount from table1 AUoi$DF(@
求和:select sum(field1) as sumvalue from table1 M.d{:&@`%
平均:select avg(field1) as avgvalue from table1 622mNY
最大:select max(field1) as maxvalue from table1 ms
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最小:select min(field1) as minvalue from table1 3Du&KZ
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11、说明:几个高级查询运算词 y~1UU3k5
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A: UNION 运算符 e7/J:n$
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。 GG;M/}E9
B: EXCEPT 运算符 b]Rn Cu"
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。 9A3Q&@,
C: INTERSECT 运算符 &)fPz-s
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。 X~G"TT$)
注:使用运算词的几个查询结果行必须是一致的。 x`%;Q@G
12、说明:使用外连接 tq@<8?
A、left outer join: LiQs;$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。 IwFg1\>
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 ffm19 B=
B:right outer join: 3=dGz^Zdv:
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。 gNs@Q!
C:full outer join: 1
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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。 FL/y{;
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二、提升 9z_Gf]J~
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .,m$Cm
法一:select * into b from a where 1<>1 IO>Cy o
法二:select top 0 * into b from a [ Q=)f
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d-N<VVcy\
insert into b(a, b, c) select d,e,f from b; ])~*)I~Y
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Q6%m}R
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 D9H|]W ~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <ze'o.c
4、说明:子查询(表名1:a 表名2:b) C)#:zv m
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) aQFYSl
5、说明:显示文章、提交人和最后回复时间 MQ\:/]a
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2E2J=Do
6、说明:外连接查询(表名1:a 表名2:b) 6tG9PG98q9
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,=o q)Fm]
7、说明:在线视图查询(表名1:a ) .# j)YG
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5/P?@`/eT
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 }(M<sEK~
select * from table1 where time between time1 and time2 yo
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select a,b,c, from table1 where a not between 数值1 and 数值2 ,=6Eju#P
9、说明:in 的使用方法 @[
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select * from table1 where a [not] in ('值1','值2','值4','值6') VWfrcSZg6M
10、说明:两张关联表,删除主表中已经在副表中没有的信息 mW8CqW\Q5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RNX}W lo-s
11、说明:四表联查问题: [.<vISRir
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... zy$hDy0
12、说明:日程安排提前五分钟提醒 )\VUAD%~e7
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,~G _3Oz
13、说明:一条sql 语句搞定数据库分页 CF42KNq
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 YLobBtXc9
14、说明:前10条记录 Ubn5tN
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select top 10 * form table1 where 范围 i7fpl
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.) b> 2u>4
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) y-sQ"HPN
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 yuI5#
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(select a from tableA ) except (select a from tableB) except (select a from tableC) u%}vTCg*p
17、说明:随机取出10条数据 )[nzmL*w
select top 10 * from tablename order by newid() sUbZVPDr
18、说明:随机选择记录 RE"}+D
select newid() gscsB4<
19、说明:删除重复记录 ZklidHL');
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) wau81rSd
20、说明:列出数据库里所有的表名 79x^zqLb
select name from sysobjects where type='U' =C#,aoa!
21、说明:列出表里的所有的 4vBbP;ELWq
select name from syscolumns where id=object_id('TableName')
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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。 `fc*/D
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 &Puu Xz<
显示结果: fG,qax`:c
type vender pcs ^x/0*t5};z
电脑 A 1 8~2A"<{ub
电脑 A 1 }JlQQ
光盘 B 2 z>y,}#D?C
光盘 A 2 9w0 ^=
手机 B 3 n:<avl@o<
手机 C 3 {v`wQM[
23、说明:初始化表table1 dr/!wr'&hS
TRUNCATE TABLE table1 {5%<@<?)
24、说明:选择从10到15的记录 X^xu$d6
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4El{2cfA
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三、技巧 #4cuNX5m%
1、1=1,1=2的使用,在SQL语句组合时用的较多 8u+ (+25
"where 1=1" 是表示选择全部 "where 1=2"全部不选, +pe_s&
如: )YnB6@=nyk
if @strWhere !='' |}mBW@ah
begin =G=.THRUk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere i:[B#|%
end :'!?dszS
else cL1cBWd
begin 2RE }l=h5
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' le[5a=e(
end t}oxHEa V
我们可以直接写成 &12aI|u^<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +[F9Q,bH@b
2、收缩数据库 Hpsg[d)!
--重建索引 ;TW@{re
DBCC REINDEX ,2kWj7H%7
DBCC INDEXDEFRAG c"QH-sE
--收缩数据和日志 *i$+i
DBCC SHRINKDB Wq>j;\3b3
DBCC SHRINKFILE nK96A.B%p
3、压缩数据库 3IJIeG>
dbcc shrinkdatabase(dbname) uP*>-s'm
4、转移数据库给新用户以已存在用户权限 "?S#vUS+ 2
exec sp_change_users_login 'update_one','newname','oldname' qrOTb9&y
go {'}Ofj
5、检查备份集 =_,OucKkYG
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :YV!;dKJ
6、修复数据库 xHL{3^
ALTER DATABASE [dvbbs] SET SINGLE_USER +zw<iB)J
GO =8J\;h
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK hQet?*diU
GO 6Q wL
ALTER DATABASE [dvbbs] SET MULTI_USER qK#* UR0%
GO .#Sd|C]R7
7、日志清除 8;Pdd1GyUL
SET NOCOUNT ON (ZI&'"H
DECLARE @LogicalFileName sysname, I'yhxymZ;
@MaxMinutes INT, 0 /H1INve
@NewSize INT 1zp,Suv
USE tablename -- 要操作的数据库名 }h]:I'R!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 6 8_UQ.
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )0'O!O
@NewSize = 1 -- 你想设定的日志文件的大小(M) $u"K1Q3
-- Setup / initialize 5VPuHY2
DECLARE @OriginalSize int 6>vj({,1Y*
SELECT @OriginalSize = size 0<Pe~i_=
FROM sysfiles @ ?%"nK
WHERE name = @LogicalFileName i2!{.*.
SELECT 'Original Size of ' + db_name() + ' LOG is ' + :8)4:4$^
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + K8RloDjk_A
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' uV\=EDno
FROM sysfiles vu#:D1/BB
WHERE name = @LogicalFileName <w:fR|O
CREATE TABLE DummyTrans C<7J5
(DummyColumn char (8000) not null) ! TRiFD
DECLARE @Counter INT, B}!n6j`
@StartTime DATETIME, 97&6i TYA
@TruncLog VARCHAR(255) |LjCtm)@+
SELECT @StartTime = GETDATE(), ca`=dwe>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' --/ .
DBCC SHRINKFILE (@LogicalFileName, @NewSize) P]x@h
EXEC (@TruncLog) O;zW'*c+
-- Wrap the log if necessary. 4u&l@BUr
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired x*)Wl!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) lW2qVR
AND (@OriginalSize * 8 /1024) > @NewSize odhgIl&u
BEGIN -- Outer loop. sy#Gb#=#
SELECT @Counter = 0 yqYX<<!V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) RoiMvrJQP
BEGIN -- update =kCpCpET
INSERT DummyTrans VALUES ('Fill Log') 9\n}!{@i
DELETE DummyTrans 8uu:e<PLv
SELECT @Counter = @Counter + 1 >\i{,F=U7
END 0-#ct1-
EXEC (@TruncLog) {C6Yr9
END Y}[r`}={
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Fd91Y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + FUOvH85f
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N0Y!
FROM sysfiles dG|\geD
WHERE name = @LogicalFileName UnMDdJ\
DROP TABLE DummyTrans LTCjw_<7
SET NOCOUNT OFF @z,'IW74V
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' h?O-13v
9、存储更改全部表 %Wu8RG}
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch MdKZH\z/
@OldOwner as NVARCHAR(128), :L?zk"0C
@NewOwner as NVARCHAR(128) q<UqGj7#
AS S
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DECLARE @Name as NVARCHAR(128) ^:q(ksssY
DECLARE @Owner as NVARCHAR(128) ht-6_]+ME
DECLARE @OwnerName as NVARCHAR(128) kOjq LA
DECLARE curObject CURSOR FOR qI"mW@G~H
select 'Name' = name, &0lNj@/
'Owner' = user_name(uid) kP6r=HH@
from sysobjects l&yR-FJ7KY
where user_name(uid)=@OldOwner <)&ykcB
order by name ruW6cvsvet
OPEN curObject (+U!#T]'D
FETCH NEXT FROM curObject INTO @Name, @Owner ML]?`qv '
WHILE(@@FETCH_STATUS=0) }s|v-gRM{
BEGIN &]M<G)9
if @Owner=@OldOwner 5N6%N1
begin `BvcIn4do
set @OwnerName = @OldOwner + '.' + rtrim(@Name) n}+
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exec sp_changeobjectowner @OwnerName, @NewOwner p\HXE4d'
end IW46-;l7
-- select @name,@NewOwner,@OldOwner k^L (q\D
FETCH NEXT FROM curObject INTO @Name, @Owner j C@^/rMh
END l)|CPSN?w
close curObject vB,N6~r>
deallocate curObject N7;2BUIXJ
GO M-Js"cB[
10、SQL SERVER中直接循环写入数据 Pf!K()<uJ
declare @i int 4VooU [Ka(
set @i=1 FD6|>G
while @i<30 X}Csl~W8in
begin (0][hdI~B
insert into test (userid) values(@i) oT_,k}L IX
set @i=@i+1 OW.ckYt%
end l nZ=< T
小记存储过程中经常用到的本周,本月,本年函数 hb_Ia]b
Dateadd(wk,datediff(wk,0,getdate()),-1) jv7zvp
Dateadd(wk,datediff(wk,0,getdate()),6) Md~mI8
Dateadd(mm,datediff(mm,0,getdate()),0) UxW>hbzr&V
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) r`krv-,O$
Dateadd(yy,datediff(yy,0,getdate()),0) FxUH?%w
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) SAoqq
上面的SQL代码只是一个时间段 ^\CQWgY(
Dateadd(wk,datediff(wk,0,getdate()),-1) (&B &
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Dateadd(wk,datediff(wk,0,getdate()),6) b)V[d8IA
就是表示本周时间段. 7OZs~6(
下面的SQL的条件部分,就是查询时间段在本周范围内的: ^NCH)zK]v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -{w&ya4X
而在存储过程中 @fY!@xSf
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) wS5hXTb"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Soa.thP