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。 Z83A1`!.|
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一、基础 Y|eB;Dm1q
1、说明:创建数据库 E'|@hL-jn
CREATE DATABASE database-name `~zY!sK
2、说明:删除数据库 JZQT}
drop database dbname Rj&V~or
3、说明:备份sql server g. V6:>,
--- 创建 备份数据的 device )sWC5\
USE master FyZp,uD
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' mTG v*=l
--- 开始 备份 n9.` 5BH7/
BACKUP DATABASE pubs TO testBack ;J"b% ~Gn
4、说明:创建新表 9|Z25_sS
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1
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根据已有的表创建新表: gv7(-I
A:create table tab_new like tab_old (使用旧表创建新表) k)VoDxMKK
B:create table tab_new as select col1,col2... from tab_old definition only k5]M~"
5、说明:删除新表 U#=Q`
drop table tabname kHj|:,'sV
6、说明:增加一个列 Ne^md
Alter table tabname add column col type !!NVx\a
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。 +bi%4DA
7、说明:添加主键: Alter table tabname add primary key(col) NXQdy g,
说明:删除主键: Alter table tabname drop primary key(col) GEr]zMYG[A
8、说明:创建索引:create [unique] index idxname on tabname(col....) dA;f`Bi;Q
删除索引:drop index idxname i3T]<&+j5
注:索引是不可更改的,想更改必须删除重新建。 Dps0$fc
9、说明:创建视图:create view viewname as select statement a78&<
删除视图:drop view viewname j5lSu~
10、说明:几个简单的基本的sql语句 /ESmQc:DWB
选择:select * from table1 where 范围 Zj )Bd*a
插入:insert into table1(field1,field2) values(value1,value2) KMsm2~P
删除:delete from table1 where 范围 ?eUhHKS5
更新:update table1 set field1=value1 where 范围 aE0yO#=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Iu`B7UOF
排序:select * from table1 order by field1,field2 [desc] a?]Ow J
总数:select count as totalcount from table1 'je=.{[lWt
求和:select sum(field1) as sumvalue from table1 7<W7pXDp
平均:select avg(field1) as avgvalue from table1 <VB;J5Rv
最大:select max(field1) as maxvalue from table1 xngK_n
最小:select min(field1) as minvalue from table1 $_N<! h*\
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11、说明:几个高级查询运算词 i#$N,kt
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A: UNION 运算符 >3HLm3 T
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。 6 /T_+K.k
B: EXCEPT 运算符 YN
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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。 '5V2{k$4U
C: INTERSECT 运算符 A;~u"g 'z&
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 52-Gk2dp
注:使用运算词的几个查询结果行必须是一致的。 c hE~UQ
12、说明:使用外连接 =;(w Bj
A、left outer join: pgg4<j_mn
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 _h#SP+>
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5f&+(Wqw
B:right outer join: *M*:3v
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 vO#4$,
C:full outer join: !MNo
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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。 ]ee%=+'
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二、提升 '2+Rb7V
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) $E;`Y|r%WK
法一:select * into b from a where 1<>1 HbWl:y U
法二:select top 0 * into b from a g0-hN%=6
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #S+GI!
insert into b(a, b, c) select d,e,f from b; MqXN,n+`k
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) +'qzk>B
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 nKn,i$sO/.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 31b9pi}nf
4、说明:子查询(表名1:a 表名2:b) Z{/0P
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) 9N^&~O|1
5、说明:显示文章、提交人和最后回复时间 PfTjC"`,
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \]
6、说明:外连接查询(表名1:a 表名2:b) 3RpDIl`0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c d,j"8\@
7、说明:在线视图查询(表名1:a ) |sWH!:]49
select * from (SELECT a,b,c FROM a) T where t.a > 1; #7OUqp
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 oWGtKtDhH
select * from table1 where time between time1 and time2 JCNZtWF
select a,b,c, from table1 where a not between 数值1 and 数值2 qv<[f=X9|
9、说明:in 的使用方法 +.UdEIR";M
select * from table1 where a [not] in ('值1','值2','值4','值6') 9H5S@w[je
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Qn>0s
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) (I~-mzu\
11、说明:四表联查问题: ZgCG'SU
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 ..... 56(S[
12、说明:日程安排提前五分钟提醒 Y=JfV
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (hTe53d<S?
13、说明:一条sql 语句搞定数据库分页 o$I% 1
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 &-#!]T-P:E
14、说明:前10条记录 e=KA|"vxh
select top 10 * form table1 where 范围 Y>z~0$
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.) Y4,~s64e
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) VZNMom,Wr
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 ;' !G?)PZ
(select a from tableA ) except (select a from tableB) except (select a from tableC) +o)o4l%3
17、说明:随机取出10条数据 T
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select top 10 * from tablename order by newid() Kx.I'_Qk
18、说明:随机选择记录 =\Td~>
select newid() {f]K3V
19、说明:删除重复记录 nunTTE,iq%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) fw@n[u{~
20、说明:列出数据库里所有的表名 \4y7!
select name from sysobjects where type='U' ,.Ac= "f
21、说明:列出表里的所有的 D2x-Wa
select name from syscolumns where id=object_id('TableName') +Ze HZjd
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。 ^`NU:"
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 ia!t~~f
显示结果: \nM$qr'`B
type vender pcs 7a.$tT
电脑 A 1 Iy8>9m'5
电脑 A 1 Uu xbN-u
光盘 B 2 ]Ga }+^
光盘 A 2 Eh\0gQ=
手机 B 3 o9-b!I2
手机 C 3 dD@k{5
23、说明:初始化表table1 VA*~RS
TRUNCATE TABLE table1 :eqDEmr>
24、说明:选择从10到15的记录 -?gr3rV@
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc i8A{DMc,U
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三、技巧 BG!;9Z{u
1、1=1,1=2的使用,在SQL语句组合时用的较多 cwiHHf>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [|PVq#(
如: NQzpgf|h
if @strWhere !='' jH26-b<
begin $ )ps~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sU"D%G
end %''z~LzJ8
else rug^_d =B
begin K8CjZpzq
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `WvNN>R
end |r*btyOJk
我们可以直接写成 %/!n]g-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere vq yR aaMf
2、收缩数据库 S'~Zlv3`
--重建索引 :Z|lGH
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DBCC REINDEX c(jF^
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DBCC INDEXDEFRAG d5$2*h{^v
--收缩数据和日志 V XEA.Mko
DBCC SHRINKDB JEq0 {_7
DBCC SHRINKFILE cn1CM'Ru
3、压缩数据库 ~7aBli=
dbcc shrinkdatabase(dbname) ~#3h-|]*
4、转移数据库给新用户以已存在用户权限 UO(B>Abp
exec sp_change_users_login 'update_one','newname','oldname' MJ^NRT0?b
go
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5、检查备份集 [9S\3&yoh
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' No8 ~~
6、修复数据库 PGZ .\i
ALTER DATABASE [dvbbs] SET SINGLE_USER kb<Nuw
GO u=B_c A}:
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9An_zrJ%i
GO fRKO> /OT
ALTER DATABASE [dvbbs] SET MULTI_USER 5HP6o
GO ?d`?Ss;v
7、日志清除 ZzfGs
SET NOCOUNT ON MK"PCE5^i6
DECLARE @LogicalFileName sysname, c|q!C0X[
@MaxMinutes INT, sXm8KV
@NewSize INT (5[|h
USE tablename -- 要操作的数据库名 x]umh{H~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 K|$Dnma^n
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ^)=c74;;
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]UyIp`nV;
-- Setup / initialize Qo+_:N
DECLARE @OriginalSize int l/[0N@r~
SELECT @OriginalSize = size %jEdgD%xV
FROM sysfiles >xu}eWSz
WHERE name = @LogicalFileName QW :-q(s
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^L}fj$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "(j.:jayd
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <]I[|4J 7
FROM sysfiles -Si'[5@
WHERE name = @LogicalFileName UKyOkuY:w
CREATE TABLE DummyTrans rQT@:$)
(DummyColumn char (8000) not null) Hb5^+.xur
DECLARE @Counter INT, v|acKux=t
@StartTime DATETIME, C$`z23E
@TruncLog VARCHAR(255) 4~-"k{Xt
SELECT @StartTime = GETDATE(), b}'XDw
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Qj(q)!Ku
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "'p;Udt/Qm
EXEC (@TruncLog) oj*5m+:>a
-- Wrap the log if necessary. t{?U NW
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired R?3^Kx
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^S!^$d*
AND (@OriginalSize * 8 /1024) > @NewSize q,-bw2
BEGIN -- Outer loop. yv| |:wZC
SELECT @Counter = 0 4"72
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) TTcMIMyLT
BEGIN -- update b*=eMcd
INSERT DummyTrans VALUES ('Fill Log') m}w~ d /
DELETE DummyTrans H
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SELECT @Counter = @Counter + 1 z VleJ!d
END prE~GO7Z
EXEC (@TruncLog) |0YDCMq(
END \(Z'@5vC
SELECT 'Final Size of ' + db_name() + ' LOG is ' + lot7S XvK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + g(xuA^~J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 4L#q?]$
FROM sysfiles gaBt;@?:Q
WHERE name = @LogicalFileName -;=0dfC(
DROP TABLE DummyTrans b0PqP<{ t
SET NOCOUNT OFF tcOgF:
8、说明:更改某个表 Q" BIk
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exec sp_changeobjectowner 'tablename','dbo' 8
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9、存储更改全部表 7eb^^a?
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %g7 !4
@OldOwner as NVARCHAR(128), /h'V1zL#
@NewOwner as NVARCHAR(128) k&|L"N|w
AS
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DECLARE @Name as NVARCHAR(128) B$A`-
DECLARE @Owner as NVARCHAR(128) Lf _`8Ux
DECLARE @OwnerName as NVARCHAR(128) 8_0j^oh
DECLARE curObject CURSOR FOR wN/d
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select 'Name' = name, CuRYtY@9
'Owner' = user_name(uid) r@L19d)J
from sysobjects Q?Vq/3K;
where user_name(uid)=@OldOwner KK"uSC
order by name nxH=Ut7{
OPEN curObject ^t4T8ejn
FETCH NEXT FROM curObject INTO @Name, @Owner -U;2
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WHILE(@@FETCH_STATUS=0) I3uS?c
BEGIN dr3#?%
if @Owner=@OldOwner 5{cbcuG
begin i-Ck:-J
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 4Z>KrFO
exec sp_changeobjectowner @OwnerName, @NewOwner nQ >?{"
end d
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-- select @name,@NewOwner,@OldOwner q9rY++Tv
FETCH NEXT FROM curObject INTO @Name, @Owner z
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END A&_H%]{<:
close curObject &Ji!*~sE
deallocate curObject e"HA.t[A
GO ; V)pXLE
10、SQL SERVER中直接循环写入数据 <A?- *
declare @i int @ht= (Jk9
set @i=1 t.|b285e
while @i<30 dH"wYMNL
begin _bB:1l?V
insert into test (userid) values(@i) cp.c$
set @i=@i+1 iev02 8M
end \k\ {S2SU
小记存储过程中经常用到的本周,本月,本年函数 GUyMo@g
Dateadd(wk,datediff(wk,0,getdate()),-1) Rn6;@Cw
Dateadd(wk,datediff(wk,0,getdate()),6) "H I&dC
Dateadd(mm,datediff(mm,0,getdate()),0) sd|5oz)
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kj_o I5<'
Dateadd(yy,datediff(yy,0,getdate()),0) ? pq#|PI)
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5,
上面的SQL代码只是一个时间段 /KDKA)
Dateadd(wk,datediff(wk,0,getdate()),-1) WK;X6`
Dateadd(wk,datediff(wk,0,getdate()),6) r|2Y|6@
就是表示本周时间段. fWo}gH~
下面的SQL的条件部分,就是查询时间段在本周范围内的: h:{rjXK
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Wj0=cIb
而在存储过程中 NzB"u+jB
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .$nQD.X
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Q;A1&UA2