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。 =)w#?DGpj
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一、基础 %E [HMq<H
1、说明:创建数据库 }EJ/H3<
CREATE DATABASE database-name i;29*"
2、说明:删除数据库 hR.vJ2oa
drop database dbname 5/CF_v
3、说明:备份sql server &$l#0?Kc^
--- 创建 备份数据的 device M23r/eg]
USE master mwI7[I2q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' uaky2SgN
--- 开始 备份 N\rL ~4/
BACKUP DATABASE pubs TO testBack MGre_=Dm_
4、说明:创建新表 G68@(<<Z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;=6EBP%
根据已有的表创建新表: ,^DP
A:create table tab_new like tab_old (使用旧表创建新表) B^ddi
B:create table tab_new as select col1,col2... from tab_old definition only A<( DYd1H
5、说明:删除新表 Ea-U+7JC
drop table tabname Qam48XZ >
6、说明:增加一个列 H4sc7-
Alter table tabname add column col type 1<*U:W
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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。 H(y Gh
7、说明:添加主键: Alter table tabname add primary key(col) Tb8r+~HK
说明:删除主键: Alter table tabname drop primary key(col) ojA !!Ru
8、说明:创建索引:create [unique] index idxname on tabname(col....) 64>CfU(
删除索引:drop index idxname #5{BxX&\
注:索引是不可更改的,想更改必须删除重新建。 MpIiHKQ
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9、说明:创建视图:create view viewname as select statement P|C5k5
删除视图:drop view viewname 1083p9Uh
10、说明:几个简单的基本的sql语句 ovDPnf(
选择:select * from table1 where 范围 sc6NON#
插入:insert into table1(field1,field2) values(value1,value2) %hdjQIH
删除:delete from table1 where 范围 2Vw2r@S/
更新:update table1 set field1=value1 where 范围 'G>9 iw
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \wK4bvUrX
排序:select * from table1 order by field1,field2 [desc] qOnGP{
总数:select count as totalcount from table1 l(@c
求和:select sum(field1) as sumvalue from table1 :-$8u;!M
平均:select avg(field1) as avgvalue from table1 |>.</68Z
最大:select max(field1) as maxvalue from table1 o/n4M]G
最小:select min(field1) as minvalue from table1 @g]EY&Uzl
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11、说明:几个高级查询运算词 k1s5cg=n(
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A: UNION 运算符 [9#zEURS
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。 )OVa7[-T
B: EXCEPT 运算符 (XY`1|])`
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。 gFTlP
C: INTERSECT 运算符 }d;6.~Gw
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。 <iGW~COd
注:使用运算词的几个查询结果行必须是一致的。 jp^Sw|
12、说明:使用外连接 ^Xu4N"@
A、left outer join: O}p<"3Ub
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。 (Nv-wU
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 )?c,&
B:right outer join:
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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。 ^5(d^N
C:full outer join: 5O
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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。 ts=:r
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二、提升 n\f]?B(
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9\/oL{
法一:select * into b from a where 1<>1 \k{[HfVvn
法二:select top 0 * into b from a %O<8H7e)V
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) PL3hrI 5
insert into b(a, b, c) select d,e,f from b; 4z9lk^#"X
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) M]/DKo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 a ~W
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. U%[ye0@:
4、说明:子查询(表名1:a 表名2:b) lBAu@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) m]vV.pwv
5、说明:显示文章、提交人和最后回复时间 fFWi
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Hrph>v
6、说明:外连接查询(表名1:a 表名2:b) 6 . )Xeb"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3eXIo=
7、说明:在线视图查询(表名1:a ) "Aw)0a[j1
select * from (SELECT a,b,c FROM a) T where t.a > 1; H\\FAOj
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 5Z5x\CcC3
select * from table1 where time between time1 and time2 <V Rb
select a,b,c, from table1 where a not between 数值1 and 数值2 .>P:{''
9、说明:in 的使用方法 t8rFn
select * from table1 where a [not] in ('值1','值2','值4','值6') D|Wlq~IpQ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 D}j`T
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) cC+2%q B
11、说明:四表联查问题: j0V/\Ep)T<
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 ..... Pd(_
12、说明:日程安排提前五分钟提醒 tMp!MQ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 {*[(j^OE
13、说明:一条sql 语句搞定数据库分页 { I\og
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 G -+!h4p
14、说明:前10条记录 slUi)@b
select top 10 * form table1 where 范围 -B&(&R
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.) gZ7R^]
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /F(n%8)Yq
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 W I MBwmg
(select a from tableA ) except (select a from tableB) except (select a from tableC) bv b\G
17、说明:随机取出10条数据 z ynu0X
select top 10 * from tablename order by newid() fb>$p_s]
18、说明:随机选择记录 Jww#zEK
select newid() X;Sb^c"j1
19、说明:删除重复记录 isQOt *
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) lG%697P
20、说明:列出数据库里所有的表名 +A)>
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select name from sysobjects where type='U' V[K N,o{6
21、说明:列出表里的所有的 pt,L
select name from syscolumns where id=object_id('TableName') a !%,2|U
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。 ;l
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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 Fb=uN
显示结果: |?8nO.C~V
type vender pcs DL1nD5
电脑 A 1 !4'F z[RK
电脑 A 1 v^8sL` F
光盘 B 2 T,1qR:58
光盘 A 2 +>K&zS
手机 B 3 i/1$uQ
手机 C 3 >7%T%2N
23、说明:初始化表table1 G8klWZAJ
TRUNCATE TABLE table1 f:<BUqa
24、说明:选择从10到15的记录 f17E2^(I(}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }^ ,D~b-nB
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三、技巧 #S'uqP!
1、1=1,1=2的使用,在SQL语句组合时用的较多 >RAg63!`
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 4n7Kz_!SVf
如: ._^ne=Lx
if @strWhere !='' L-C^7[48=
begin 9Ffam#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere zIjfxK
end tm^joK[{|J
else 'ET];iZ2
begin o,dp{+({
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 9&AO
end Oh p@ZJ!a?
我们可以直接写成 ,}gJY^X+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6&ut r!\7
2、收缩数据库 5)lcgvp
--重建索引 1p$(\
DBCC REINDEX "8ellKh
DBCC INDEXDEFRAG Kq-1 b
--收缩数据和日志 n9}BT^4 v
DBCC SHRINKDB iBSg`"S^]C
DBCC SHRINKFILE ]h(Iun
3、压缩数据库 Td'(RV
dbcc shrinkdatabase(dbname) }RI_k&;
4、转移数据库给新用户以已存在用户权限 rxu_Ssd@"
exec sp_change_users_login 'update_one','newname','oldname' C1=&Vm>g+
go <TtPwUX
5、检查备份集 m{ !$_z8:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' zdRVAcrwQ
6、修复数据库 tJrGRlB>
ALTER DATABASE [dvbbs] SET SINGLE_USER 4=Ru{ewRV
GO xL"J?Gy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~44u_^a
GO XxS#~J?:_
ALTER DATABASE [dvbbs] SET MULTI_USER &zX W
GO H/x0'
7、日志清除 x"e;T,c
SET NOCOUNT ON @qp6Y_,E[
DECLARE @LogicalFileName sysname, `v``}8tm
@MaxMinutes INT, 8VMA~7^
@NewSize INT \]]K{DO
USE tablename -- 要操作的数据库名 B=& [Z2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~rdS#f&R2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ZF[W<Q
@NewSize = 1 -- 你想设定的日志文件的大小(M) 1LRP
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-- Setup / initialize [,AFtg[
DECLARE @OriginalSize int
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SELECT @OriginalSize = size t8EI"|
FROM sysfiles 9=MNuV9/s
WHERE name = @LogicalFileName }_zN%Tf~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -@"3`uv"
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [+dCA
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =JzzrM|V*
FROM sysfiles E4892B:`
WHERE name = @LogicalFileName ?96r7C|
CREATE TABLE DummyTrans xOj#%;
(DummyColumn char (8000) not null) `mz}D76~#
DECLARE @Counter INT, C?gqX0[ q
@StartTime DATETIME, HJ7A/XW
@TruncLog VARCHAR(255) 8$_{R!x
SELECT @StartTime = GETDATE(), <1*.:CL"s
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \#:
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) *eIX"&ba
EXEC (@TruncLog) 8p%0d`sX
-- Wrap the log if necessary. SQ4^sk_!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired z:f&k}(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) g]?pY
AND (@OriginalSize * 8 /1024) > @NewSize Q^2dZXk~
BEGIN -- Outer loop. '2lzMc>wvP
SELECT @Counter = 0 6GunEYK!N8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -^m?%_<50l
BEGIN -- update 6)uBUM;i
INSERT DummyTrans VALUES ('Fill Log') 5tbCx!tL
DELETE DummyTrans 0q"4\#4l
SELECT @Counter = @Counter + 1 `KA==;0
END =M;F&;\8
EXEC (@TruncLog) Tty'ysH
END yO)xN=o^\
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }? / Blr
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lz#.f,h
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7gf(5p5ZV
FROM sysfiles + m-88
WHERE name = @LogicalFileName #ay/VlD@
DROP TABLE DummyTrans NgyEy n
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SET NOCOUNT OFF
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8、说明:更改某个表 FJtmRPP[r
exec sp_changeobjectowner 'tablename','dbo' _`?cBu`
9、存储更改全部表 1*hE bO
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _dd! nU\A|
@OldOwner as NVARCHAR(128), kiM:(=5
@NewOwner as NVARCHAR(128) LP#wE~K"b
AS Eu(QeST\
DECLARE @Name as NVARCHAR(128) IN bV6jZL
DECLARE @Owner as NVARCHAR(128) v3Vve:}+
DECLARE @OwnerName as NVARCHAR(128) 3xs<w7
DECLARE curObject CURSOR FOR Lf5zHUH
select 'Name' = name, MQwxQ{
'Owner' = user_name(uid) (2H
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from sysobjects UV D D)
where user_name(uid)=@OldOwner M@{?#MkS%
order by name Y
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OPEN curObject HC$%"peN1b
FETCH NEXT FROM curObject INTO @Name, @Owner Wf3BmkZzz
WHILE(@@FETCH_STATUS=0) GbQi3%
BEGIN #9|&;C5',!
if @Owner=@OldOwner p"%D/-%Gu
begin qBBCnT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g8MW6Y
exec sp_changeobjectowner @OwnerName, @NewOwner X|{T ljn
end )]C]K B
-- select @name,@NewOwner,@OldOwner rk1,LsZVS
FETCH NEXT FROM curObject INTO @Name, @Owner #E!^oZm<Z
END #b[bgxm
close curObject GO"|^W
deallocate curObject bfz7t!A)A
GO ~
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10、SQL SERVER中直接循环写入数据 uG7]s]Wdz;
declare @i int $f3 IO#N
set @i=1 <)T| HKx
while @i<30 ' J@J$#6
begin >(a35 b$
insert into test (userid) values(@i) n3~axRPO
set @i=@i+1 ; H ;h[
end 3!p`5hJd
小记存储过程中经常用到的本周,本月,本年函数 s;TB(M~i[
Dateadd(wk,datediff(wk,0,getdate()),-1) (%L/|F_
Dateadd(wk,datediff(wk,0,getdate()),6) 8C3oi&av/{
Dateadd(mm,datediff(mm,0,getdate()),0) -yqgs>R(d
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) A3/[9}(U
Dateadd(yy,datediff(yy,0,getdate()),0) I^k&v V
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) @)h>vg
上面的SQL代码只是一个时间段 Yg.[R]
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Dateadd(wk,datediff(wk,0,getdate()),-1) HZ'rM5Kq
Dateadd(wk,datediff(wk,0,getdate()),6) F@Sk=l(
就是表示本周时间段. z<5 5[~3
下面的SQL的条件部分,就是查询时间段在本周范围内的: TbD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) =8 @DYz'
而在存储过程中 N[W#wYbH
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 0C :8X
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =|i_T%a