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。 QbF!V%+a's
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一、基础 *u2pk>y)
1、说明:创建数据库 zL1*w@6
CREATE DATABASE database-name "kLu]M<
2、说明:删除数据库 <Ae1YHUY
drop database dbname :'L^zGf
3、说明:备份sql server MH"{N
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--- 创建 备份数据的 device
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USE master #E[{
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' x=UwyZ
--- 开始 备份 uafSz@`
BACKUP DATABASE pubs TO testBack ICJp-
4、说明:创建新表 Ez3>}E,
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L(p{>Ykcc
根据已有的表创建新表: H`js1b1n
A:create table tab_new like tab_old (使用旧表创建新表) IfGmA.O
B:create table tab_new as select col1,col2... from tab_old definition only 6#,VnS)`q
5、说明:删除新表 4CzT<cp
drop table tabname E3pnu.;U:_
6、说明:增加一个列 mfYY?]A*+
Alter table tabname add column col type )1PZ#
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。 X3C"A|HE9
7、说明:添加主键: Alter table tabname add primary key(col) XHX\+&6
说明:删除主键: Alter table tabname drop primary key(col) .{cka]9WJz
8、说明:创建索引:create [unique] index idxname on tabname(col....) u?OyvvpH
删除索引:drop index idxname B.wRZDEvc
注:索引是不可更改的,想更改必须删除重新建。 _QD##`<
9、说明:创建视图:create view viewname as select statement YLr<^G-v
删除视图:drop view viewname aV^wTs#2I
10、说明:几个简单的基本的sql语句 8Z=d+}Gg<
选择:select * from table1 where 范围 E]^wsS>=
插入:insert into table1(field1,field2) values(value1,value2) +=XDNSw
删除:delete from table1 where 范围 oKl^Ttr
更新:update table1 set field1=value1 where 范围 TRQ@=.
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! [n[!RddY
排序:select * from table1 order by field1,field2 [desc] 9?VyF'r=
总数:select count as totalcount from table1 ]Iku(<*Ya
求和:select sum(field1) as sumvalue from table1 9#:b+Amzz
平均:select avg(field1) as avgvalue from table1 !xU1[,9
最大:select max(field1) as maxvalue from table1 ]et4B+=i
最小:select min(field1) as minvalue from table1 q*^Y8s~3I
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11、说明:几个高级查询运算词 d)'am
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A: UNION 运算符 P'.M.I@
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。 bB|UQaCl
B: EXCEPT 运算符 c:
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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。 `$IuN*
C: INTERSECT 运算符 6g/ <FM
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 2>l
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注:使用运算词的几个查询结果行必须是一致的。 ~$#"'Tl4J
12、说明:使用外连接 (dOC ^i
A、left outer join:
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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。 QZcdfJck=+
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 GpjyF_L
B:right outer join: %/l9$>{
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 8>Y
C:full outer join: -ZTe#@J
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 I~LN)hqd o
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二、提升 }b9"&io
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) (x}>tm
法一:select * into b from a where 1<>1 L* k[Vc
法二:select top 0 * into b from a zEG6T *
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ]0`*gKA
insert into b(a, b, c) select d,e,f from b; R{s&6
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) "62vwWrwO
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (=v :@\r
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `
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4、说明:子查询(表名1:a 表名2:b) p0 @,-
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) `[hc{ynO|
5、说明:显示文章、提交人和最后回复时间 X^!n'$^u
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {1RI!#[\
6、说明:外连接查询(表名1:a 表名2:b) r(ej=aR
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )E--E+j
7、说明:在线视图查询(表名1:a ) R,mOV8y"W[
select * from (SELECT a,b,c FROM a) T where t.a > 1; Fai_v{&?
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 k
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select * from table1 where time between time1 and time2 ` ZO#n
select a,b,c, from table1 where a not between 数值1 and 数值2 Z(fXN$
9、说明:in 的使用方法 ^[K3]*!@
select * from table1 where a [not] in ('值1','值2','值4','值6') r-M:YB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 +.Pv:7gh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) {Y>5 [gp
11、说明:四表联查问题: GZxM44fP
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 ..... a;=)`
12、说明:日程安排提前五分钟提醒 2nSX90@:
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;x 9_
13、说明:一条sql 语句搞定数据库分页 XLEEd?Vct9
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 {!?
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14、说明:前10条记录 !N\<QRb\q
select top 10 * form table1 where 范围 _zAHN0d
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.) R+'$V$g\X
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w! J|KM
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 ET]PF ,`
(select a from tableA ) except (select a from tableB) except (select a from tableC) 6OBe^/ZRt
17、说明:随机取出10条数据 d~i WV6Va
select top 10 * from tablename order by newid() ?gknJ:
18、说明:随机选择记录 &`#k1t'
select newid() VrV
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19、说明:删除重复记录 -^ )0c
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 3NI3b-7
20、说明:列出数据库里所有的表名 \!!qzrq
select name from sysobjects where type='U' \Wdl1 =`
21、说明:列出表里的所有的 N?xZ]?T
select name from syscolumns where id=object_id('TableName') )e#KL$B)v
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 =fJDFg
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type !Zowe*`
显示结果: (mO{W
type vender pcs j_`
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电脑 A 1 s} 2TJa
电脑 A 1 D{-h2=V
光盘 B 2 "4Joou"U
光盘 A 2 ;kSRv=S
手机 B 3 eWKFs)C]
手机 C 3 2nNBX2o&_
23、说明:初始化表table1 8*nv+
TRUNCATE TABLE table1 w_c)iJ
24、说明:选择从10到15的记录 y^PQgzm]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc d:Y!!LV-@L
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三、技巧 oXC|q-(C
1、1=1,1=2的使用,在SQL语句组合时用的较多 bjn: e!}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1D*oXE9Ig
如: fL0dy[Ch@
if @strWhere !='' 9((BOq
begin D-{;;<nIr`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Xk9mJ]31LC
end lk.]!K$}
else wM$N#K@
begin `ChS$p"A
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' mf~JolucJ
end a
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我们可以直接写成 j6!C/UgQ
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "_LDs(&
2、收缩数据库 Rz sgPk
--重建索引 o,-p[1b
DBCC REINDEX ;rgg O0Y
DBCC INDEXDEFRAG jeKqS
--收缩数据和日志 |j 9d.M
DBCC SHRINKDB <z'Pj7c[
DBCC SHRINKFILE sj9j47y
3、压缩数据库 FEC`dSTI
dbcc shrinkdatabase(dbname) ^T?zR7r
4、转移数据库给新用户以已存在用户权限 KT5amct
exec sp_change_users_login 'update_one','newname','oldname' _xKIp>A
go OD@k9I[
5、检查备份集 U46qpb7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 2 m"2>gX
6、修复数据库 ;mT|0&o>#
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO Z\lJE>1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,6J{-Iu
GO CP]nk0
ALTER DATABASE [dvbbs] SET MULTI_USER -_*ux!
GO 7
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7、日志清除 ~FP4JM,y6
SET NOCOUNT ON Kw%to9eh)
DECLARE @LogicalFileName sysname, (:(Imk;9
@MaxMinutes INT, _i3?;Fds
@NewSize INT M]Kxg;
USE tablename -- 要操作的数据库名 tPp9=e2[s
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 I cJy$+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. f|v5itO2
@NewSize = 1 -- 你想设定的日志文件的大小(M) COc,
-- Setup / initialize CXQ +h
DECLARE @OriginalSize int 5dvP~sw
SELECT @OriginalSize = size WyA`V C
FROM sysfiles J-UqH3({Z,
WHERE name = @LogicalFileName mNII-XG
SELECT 'Original Size of ' + db_name() + ' LOG is ' + lU\v8!Ji
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |o@xWs@m
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ub,5~I+`
FROM sysfiles ,`pUz[wl
WHERE name = @LogicalFileName n 3eLIA{
CREATE TABLE DummyTrans ~=P#7l\o1
(DummyColumn char (8000) not null) <r>1W~bp.q
DECLARE @Counter INT, WMw|lV r
@StartTime DATETIME, C
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@TruncLog VARCHAR(255) >g>L>{
SELECT @StartTime = GETDATE(), T1-.+&<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \ u*R6z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [ML|,kq!
EXEC (@TruncLog) ;aj4V<@
-- Wrap the log if necessary. .OM^@V~T
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired op2<~v0?
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >;K!yI?0
AND (@OriginalSize * 8 /1024) > @NewSize "W b>y*S
BEGIN -- Outer loop. Q4Zw<IZv5
SELECT @Counter = 0 H2jF=U"=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *Cj<Vy
BEGIN -- update g1H$wU3eu
INSERT DummyTrans VALUES ('Fill Log') LJgGX,Kp
DELETE DummyTrans v:IpZ;^
SELECT @Counter = @Counter + 1 iW?z2%#
END qg06*$%
EXEC (@TruncLog) ip+?k<]z
END Leu93f2
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &cpqn2Z
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + -=InGm\Y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 20,}T)}Tm
FROM sysfiles \H4$9lPk
WHERE name = @LogicalFileName S'_2o?fs
DROP TABLE DummyTrans TpGnSD
SET NOCOUNT OFF >ufL RGL>
8、说明:更改某个表 V[;^{,;
exec sp_changeobjectowner 'tablename','dbo' u|+Dqe`
9、存储更改全部表 =h>jo&=Wad
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |e_'%d&
@OldOwner as NVARCHAR(128), 7~qyz]KkE
@NewOwner as NVARCHAR(128) Yq-Vwh/
AS {9XN\v=$"*
DECLARE @Name as NVARCHAR(128) :^En\YcU
DECLARE @Owner as NVARCHAR(128) X()yhe_
DECLARE @OwnerName as NVARCHAR(128) 4T>d%Tt+)
DECLARE curObject CURSOR FOR [BTOs4f
select 'Name' = name, "Ng%"Nz
'Owner' = user_name(uid) 3P *[!KI
from sysobjects [9C{\t
where user_name(uid)=@OldOwner v.6K;TY.
order by name 8U)*kmq
OPEN curObject rqWD#FB=z
FETCH NEXT FROM curObject INTO @Name, @Owner e9;5.m
WHILE(@@FETCH_STATUS=0) j,79G^/YG
BEGIN Tr.u'b(
if @Owner=@OldOwner mhgvN-? "h
begin M,vCAZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ZK4d;oa",
exec sp_changeobjectowner @OwnerName, @NewOwner 7PbwCRg
end o_sb+Vn|
-- select @name,@NewOwner,@OldOwner $/kZKoF{f
FETCH NEXT FROM curObject INTO @Name, @Owner fyF8RTm{
END xyrlR;Sk
close curObject SUb:0GUa
deallocate curObject MMy\u) 4
GO -KL5sK
10、SQL SERVER中直接循环写入数据 -PCFOm"
declare @i int T0X+\&W
set @i=1 Oj>;[O"
while @i<30 em9nuXG
begin @M*oq2U;
insert into test (userid) values(@i) f;%=S:3
set @i=@i+1 AQGl}%k_
end XI>HC'.0
小记存储过程中经常用到的本周,本月,本年函数 ':7gYP*v
Dateadd(wk,datediff(wk,0,getdate()),-1) Y~B-dx'V
Dateadd(wk,datediff(wk,0,getdate()),6) d$HPpi1LL
Dateadd(mm,datediff(mm,0,getdate()),0) r]deVd G
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) l@ 5kw]6
Dateadd(yy,datediff(yy,0,getdate()),0) ckkm}|&m
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ID~}pEQ
上面的SQL代码只是一个时间段 fD*jzj7o,
Dateadd(wk,datediff(wk,0,getdate()),-1) 4C }#lW9
Dateadd(wk,datediff(wk,0,getdate()),6) gn:&akg
就是表示本周时间段. /[I#3|
下面的SQL的条件部分,就是查询时间段在本周范围内的: }2''}-Nc
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0V+v)\4FE
而在存储过程中 tfdb9#&?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) r-AD*h@QZ
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y[';@t7CC