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。 fle0c^ =
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一、基础 j];1"50?
1、说明:创建数据库 n^Au*'
CREATE DATABASE database-name anitqy#E
2、说明:删除数据库 xXa#J)'
drop database dbname bVmvjY4
3、说明:备份sql server fbL!=]A*3
--- 创建 备份数据的 device Y_shy6"KH
USE master 8c?8X=|D7
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Alh?0 Fk3)
--- 开始 备份 '?L%F{g/9
BACKUP DATABASE pubs TO testBack ?lG;,,jc,W
4、说明:创建新表 "w1(g=n
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) XkoW L
根据已有的表创建新表: ,yi2O]5e>!
A:create table tab_new like tab_old (使用旧表创建新表) o(SuUGW
B:create table tab_new as select col1,col2... from tab_old definition only 6Wu*.53
5、说明:删除新表 InX{V|CW?
drop table tabname :,=Fx</H
6、说明:增加一个列 '!j(u@&!
Alter table tabname add column col type >?Qxpqf2
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。 :dbV2'vIQ
7、说明:添加主键: Alter table tabname add primary key(col) B(EtXB9
说明:删除主键: Alter table tabname drop primary key(col) v7$9QVze
8、说明:创建索引:create [unique] index idxname on tabname(col....) R]fYe#!"
删除索引:drop index idxname Dpp@*xX>
注:索引是不可更改的,想更改必须删除重新建。 0kz7 >v
9、说明:创建视图:create view viewname as select statement f8F1~q
删除视图:drop view viewname "x.88,T6
10、说明:几个简单的基本的sql语句 S%P3ek>3
选择:select * from table1 where 范围 `w(sXkeaI
插入:insert into table1(field1,field2) values(value1,value2) H!^C 2
删除:delete from table1 where 范围 u>
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更新:update table1 set field1=value1 where 范围 [EcV\.
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4}PeP^pj
排序:select * from table1 order by field1,field2 [desc] K+t];(
总数:select count as totalcount from table1 VG#$fRrZ
求和:select sum(field1) as sumvalue from table1 :EaiM J_=
平均:select avg(field1) as avgvalue from table1 :=B[yD!
最大:select max(field1) as maxvalue from table1 nR#a)et
最小:select min(field1) as minvalue from table1 =1&}t%<X
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11、说明:几个高级查询运算词 kt5YgW
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A: UNION 运算符 c8!j6\dC*
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。 s=}~Q&8
B: EXCEPT 运算符 r8H7TJI0
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。 6;[1Jz]?i
C: INTERSECT 运算符 rGAFp,}-f
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}aC9I
注:使用运算词的几个查询结果行必须是一致的。 DD)mN)
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12、说明:使用外连接 IFkvv1S`
A、left outer join: se"um5N-
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。 (h%|;9tF
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 nEuct4BcL}
B:right outer join: MgSp.<!
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。 xQ_:]\EZ
C:full outer join: U0ns3LirP
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。 cKSfqqPm$"
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二、提升 -!JlM@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "
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法一:select * into b from a where 1<>1 HK=CP0H
法二:select top 0 * into b from a U5 -zB)V
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~m3V]v(q7
insert into b(a, b, c) select d,e,f from b; @ICejB<
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) /6 A:J]Q_
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 2M5*bNU_:
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. WCWSLEAza
4、说明:子查询(表名1:a 表名2:b) yg.\^C
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) K7y!s :rg!
5、说明:显示文章、提交人和最后回复时间 u_hE7#i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b yDDghW'\WU
6、说明:外连接查询(表名1:a 表名2:b) `8qT['`#R
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 20S9/9ll
7、说明:在线视图查询(表名1:a ) ;N9n'Sq4
select * from (SELECT a,b,c FROM a) T where t.a > 1; Bl:{p>-q
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 Nt?2USTs-
select * from table1 where time between time1 and time2 @)S sKk|
select a,b,c, from table1 where a not between 数值1 and 数值2 zT2F&y
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9、说明:in 的使用方法 D6"~fjHh
select * from table1 where a [not] in ('值1','值2','值4','值6') {EZFx,@t
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {A!;W
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) CAA tco5
11、说明:四表联查问题: [ ((h<e
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 ..... ~k"eEV
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12、说明:日程安排提前五分钟提醒 {.0X[uAf
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0#2T0zk
13、说明:一条sql 语句搞定数据库分页 xop-f#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 _wIBm2UO
14、说明:前10条记录 &*LA_]1@
select top 10 * form table1 where 范围 Y8{T.\%\+
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.) >}xAg7\^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w50.gr7
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 I%.jc2kK
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 r|u6O F>
select top 10 * from tablename order by newid() A}
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18、说明:随机选择记录 |8&\N
select newid() qBf wN 1
19、说明:删除重复记录 )F=JkG
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 58a)&s[+
20、说明:列出数据库里所有的表名 Vq? 8u/
select name from sysobjects where type='U' FCUVP,"T
21、说明:列出表里的所有的 rQ9?N^&!%
select name from syscolumns where id=object_id('TableName') v3=&{}+j.
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。 ^\Ue7,H-
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 jb#1&L14
显示结果: 5#N"WHz!
type vender pcs v ^ FV
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电脑 A 1 QE`:jxyad
电脑 A 1 ~4p]E'b
光盘 B 2 $cp16
光盘 A 2 {66Q" H"I
手机 B 3 @1`W<WP
手机 C 3 *FI5z[8,
23、说明:初始化表table1 "^e}C@
TRUNCATE TABLE table1 N{0+C?{_
24、说明:选择从10到15的记录 )VV4HoH]8
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \.XT:B_
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三、技巧 `2Z4#$.
1、1=1,1=2的使用,在SQL语句组合时用的较多 QiQ2XW\E
"where 1=1" 是表示选择全部 "where 1=2"全部不选, oX=*MEfX
如: i`ZHjW~`
if @strWhere !='' ?[NTw./'7A
begin XSL
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere k:(e79
end xIq"[?m
else M+;!]tbc3
begin 5 O{Ip-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' { c6DT
end g z)wUQ|W
我们可以直接写成 6@,'m
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere DLg `Q0`M5
2、收缩数据库 5KA
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--重建索引 ;N> {1
DBCC REINDEX 3f7t%
DBCC INDEXDEFRAG o0-fUCmC
--收缩数据和日志 KNUMz4
DBCC SHRINKDB l{D,O?`Av
DBCC SHRINKFILE )0 42?emn
3、压缩数据库 y:^>(l #;
dbcc shrinkdatabase(dbname) C4X{Ps\
4、转移数据库给新用户以已存在用户权限 <*~BG)b
exec sp_change_users_login 'update_one','newname','oldname' tSh}0N)
go MU^xu&MB
5、检查备份集 RfVV(X
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @poMK:
6、修复数据库 >8Yrmq
ALTER DATABASE [dvbbs] SET SINGLE_USER pyb}ha
GO g)zn.]
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1_dMe%53
GO BW(DaNt^
ALTER DATABASE [dvbbs] SET MULTI_USER :n%sU*'T
GO "*H'bzK
7、日志清除 a_}BTkfHa
SET NOCOUNT ON T/spUlWu
DECLARE @LogicalFileName sysname, 9DP75 ti
@MaxMinutes INT, wYS
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@NewSize INT D+vl%(g
USE tablename -- 要操作的数据库名 $M8>SLd
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -+S~1`0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. j8ohzX[Y
@NewSize = 1 -- 你想设定的日志文件的大小(M) .AmM%I4K
-- Setup / initialize "< hx
DECLARE @OriginalSize int s+\qie
SELECT @OriginalSize = size XQg%*Rw+t
FROM sysfiles 4d3]pvv
WHERE name = @LogicalFileName ?T%K +
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4'4s EjyA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b6E8ase:F
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' w|UKMbRMU]
FROM sysfiles Kt&$Si
WHERE name = @LogicalFileName 1SJHX1CxX
CREATE TABLE DummyTrans =LeVJGF
(DummyColumn char (8000) not null) /{#_Um0.
DECLARE @Counter INT, JEkIbf?=r
@StartTime DATETIME, (HX [bG`
@TruncLog VARCHAR(255) q.hc%s2?
SELECT @StartTime = GETDATE(), :QhEu%e
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "'p+qbT8
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ;?L[]Ezzt
EXEC (@TruncLog) aK=3`q
-- Wrap the log if necessary. 4`'BaUU(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~D-OL*2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7.1E mJ
AND (@OriginalSize * 8 /1024) > @NewSize @x>$_:]
BEGIN -- Outer loop. S5[RSAbf*t
SELECT @Counter = 0 ^zluO
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) N=?kEX
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BEGIN -- update i!+3uHWu`)
INSERT DummyTrans VALUES ('Fill Log') A%2M]];%X
DELETE DummyTrans !6fpMo
SELECT @Counter = @Counter + 1 L|xen*O
END &.bR1wX
EXEC (@TruncLog) :tS>D5dz(
END zZjLt1
SELECT 'Final Size of ' + db_name() + ' LOG is ' + d}B_ll#j-
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :$Di.|l@7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' iJj?~\zp
FROM sysfiles i(cb&;Xx:A
WHERE name = @LogicalFileName ;g)Fhdy!
DROP TABLE DummyTrans =A&*SE o5
SET NOCOUNT OFF =K<I)2
8、说明:更改某个表 W/F4wEODY
exec sp_changeobjectowner 'tablename','dbo' c+K=pp@
9、存储更改全部表 uJ5%JB("E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch UFY~D"%/
@OldOwner as NVARCHAR(128), ZK_@.O+ ]
@NewOwner as NVARCHAR(128) =&g}Y
AS aD3F!Sn
DECLARE @Name as NVARCHAR(128) ~9'4w-Sy
DECLARE @Owner as NVARCHAR(128) :g:h 0'G
DECLARE @OwnerName as NVARCHAR(128) Pge }xKT
DECLARE curObject CURSOR FOR O.8m%ZjD
select 'Name' = name, )Ai%wCzw*
'Owner' = user_name(uid) F p=Q$J|
from sysobjects gm\o>YclS
where user_name(uid)=@OldOwner X\)KVn`
order by name 48NXj\L[y
OPEN curObject 6!D
FETCH NEXT FROM curObject INTO @Name, @Owner H5MAN,`
WHILE(@@FETCH_STATUS=0) #yRA.;
BEGIN ?)QBJ9F
if @Owner=@OldOwner W[Ew6)1T
begin yt#;3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) sTstc+w
exec sp_changeobjectowner @OwnerName, @NewOwner V+<AG*[
end nX aX=
-- select @name,@NewOwner,@OldOwner c]v3dHE_h
FETCH NEXT FROM curObject INTO @Name, @Owner }Z$G=;3#
END v2X0Px_
close curObject jO
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deallocate curObject _*B~ESC0
GO ]f @LhC1x
10、SQL SERVER中直接循环写入数据 fB"gM2'
declare @i int Cspm\F
set @i=1 -oT+;2\2
while @i<30 1?$!y
begin 2_~XjwKE
insert into test (userid) values(@i) nVA'O
set @i=@i+1 |}y}o:(
end Nc Mq>n
小记存储过程中经常用到的本周,本月,本年函数 6uE1&-:L
Dateadd(wk,datediff(wk,0,getdate()),-1) ;Sl0kSu
Dateadd(wk,datediff(wk,0,getdate()),6) Gqb-3ngH
Dateadd(mm,datediff(mm,0,getdate()),0) '#
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 4J2F>m40
Dateadd(yy,datediff(yy,0,getdate()),0) V~"d`j
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) wmCV%g\.d:
上面的SQL代码只是一个时间段 W$&Ets8zo
Dateadd(wk,datediff(wk,0,getdate()),-1) /;m!>{({)
Dateadd(wk,datediff(wk,0,getdate()),6) ;m:GUp^[
就是表示本周时间段. 8VGXw;(Y,d
下面的SQL的条件部分,就是查询时间段在本周范围内的: Zd/~ *ZA
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &Zy=vk*
而在存储过程中 0$Db@
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *(.^$Iq4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) s-S"\zX\D