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。 :d&^//9
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一、基础 MZpG1
1、说明:创建数据库 }d,iA FG
CREATE DATABASE database-name U%swqle4
2、说明:删除数据库 lP4A?J+Q
drop database dbname -Qs4s
3、说明:备份sql server uP'x{Pr)
--- 创建 备份数据的 device +) pO82
USE master '>GZB
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' p4\r`
--- 开始 备份 .?gpIZv
BACKUP DATABASE pubs TO testBack G8m:]!
4、说明:创建新表 rtl|zCst
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 0?D`|x_
根据已有的表创建新表: !'4HUB>+
A:create table tab_new like tab_old (使用旧表创建新表) }CR@XD}[
B:create table tab_new as select col1,col2... from tab_old definition only f0 ;Fokt(
5、说明:删除新表 qusX]Tstz
drop table tabname Us4ijR d
6、说明:增加一个列 gAy,uP~,
Alter table tabname add column col type "?I ]h
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。 6K/j,e>L
7、说明:添加主键: Alter table tabname add primary key(col) y4aW8J#
说明:删除主键: Alter table tabname drop primary key(col) vJX3fE}F
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;C1]gJZ,
删除索引:drop index idxname mk)F3[ke
注:索引是不可更改的,想更改必须删除重新建。 7XE |5G
9、说明:创建视图:create view viewname as select statement v&[Ff|>
删除视图:drop view viewname hOI|#(-
10、说明:几个简单的基本的sql语句 3y}0J @
选择:select * from table1 where 范围
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插入:insert into table1(field1,field2) values(value1,value2) l]BIFZ~
删除:delete from table1 where 范围 l{:7*U{d
更新:update table1 set field1=value1 where 范围 G(LGa2;Zg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YT)jBS~&
排序:select * from table1 order by field1,field2 [desc] HPGMR4=ANS
总数:select count as totalcount from table1 faqOGAb
求和:select sum(field1) as sumvalue from table1 :iWW2fY
平均:select avg(field1) as avgvalue from table1 3`ov?T(H
最大:select max(field1) as maxvalue from table1 $^ \8-k "
最小:select min(field1) as minvalue from table1 HZp}<7NR(7
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11、说明:几个高级查询运算词 <ID/\Qx`q
by 'P}
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A: UNION 运算符 o!q3+Pp;}
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 W\JbX<mQ
B: EXCEPT 运算符 ),9^hJ1+@
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 RAw/Q$I
C: INTERSECT 运算符 ^_6.*Mvx
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。 +Y7"!wYR>
注:使用运算词的几个查询结果行必须是一致的。 OhC%5=a7
12、说明:使用外连接 ~j%g?;#*
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。 B d#D*"gx
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 T%{qwZc+mJ
B:right outer join: )bJS*#
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。 jH+ddBVA
C:full outer join: ^gP pmb<x
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。 G}!dm0s$
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二、提升 }m!L2iK4qk
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) q J)[2:.G
法一:select * into b from a where 1<>1 +n]z'pijb
法二:select top 0 * into b from a XH9Y|FX%#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) TqzL] 'NS+
insert into b(a, b, c) select d,e,f from b; QWqEe|}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) TvV_Tz4e
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $yd "bJK
4、说明:子查询(表名1:a 表名2:b) G/l 28yt
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) JHF<vyt5<
5、说明:显示文章、提交人和最后回复时间 R#D>m8&}3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _gAU`aO^
6、说明:外连接查询(表名1:a 表名2:b) R07 7eX
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c >A'Q9Tia;
7、说明:在线视图查询(表名1:a ) ~
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select * from (SELECT a,b,c FROM a) T where t.a > 1; ]yc&ffe%
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 xqP DL9\
select * from table1 where time between time1 and time2 J.nJ@?O+
select a,b,c, from table1 where a not between 数值1 and 数值2 --t"X<.z
9、说明:in 的使用方法 F]_w~1
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select * from table1 where a [not] in ('值1','值2','值4','值6') kU*Fif
10、说明:两张关联表,删除主表中已经在副表中没有的信息 5somoV B
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [SnnOq Ww
11、说明:四表联查问题: a]JQZo1$
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 ..... Me*woCos'
12、说明:日程安排提前五分钟提醒 ]Ut fI
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Bo)N<S_=^
13、说明:一条sql 语句搞定数据库分页 -SyQ`V)T7N
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 $ mH'%YDIl
14、说明:前10条记录 -0pAj}_2}
select top 10 * form table1 where 范围 6p=OM=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.) S,Y\ox-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) x{GKz#
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 d&N[\5q
(select a from tableA ) except (select a from tableB) except (select a from tableC) _'CYS3-P3
17、说明:随机取出10条数据 hv]}b'M$
select top 10 * from tablename order by newid() S"}G/lBx.
18、说明:随机选择记录 zO@7V>2
select newid() Wciw6.@
19、说明:删除重复记录 71g\fGG\
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *hm;C+<~
20、说明:列出数据库里所有的表名 kNqIPvuMr
select name from sysobjects where type='U' rM|] }M=_V
21、说明:列出表里的所有的 N:4oVi@Je
select name from syscolumns where id=object_id('TableName') n ]K`ofjl^
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。 ~s$
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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 fo$5WTY
显示结果: PO$
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type vender pcs S2^Ckg
电脑 A 1 0=WZ 8|R
电脑 A 1 W*S!}ZT`
光盘 B 2 z_gjC%(y
光盘 A 2 +Jf45[D
手机 B 3 a>_Cxsb&`
手机 C 3 @i" ^b
23、说明:初始化表table1 834E
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TRUNCATE TABLE table1 2D?V0>/
24、说明:选择从10到15的记录 *8WcRx
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Syf0dp3
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三、技巧 &efwfnG<
1、1=1,1=2的使用,在SQL语句组合时用的较多 W-72&\7
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 7H,p/G?]k
如: y*f5_
if @strWhere !='' P%CNu
begin 8J5{}4s\f
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CH`_4UAX%
end L\`uD[g
else vWGjc2_
begin 4mqA*c%6S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' iJ7?6)\
end i&%/]Nq
我们可以直接写成 v ?9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere t%B ,ATW
2、收缩数据库 nMBKZ
--重建索引 Ah|,`0dw
DBCC REINDEX G"xa"hGF
DBCC INDEXDEFRAG 9=-d/y?
--收缩数据和日志 4a]$4LQV
DBCC SHRINKDB [|:kS
DBCC SHRINKFILE Lwy9QZL
3、压缩数据库 XSw!_d
dbcc shrinkdatabase(dbname) nc0!ag
4、转移数据库给新用户以已存在用户权限 jRhOo%p
exec sp_change_users_login 'update_one','newname','oldname' 0Ud.u
go
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5、检查备份集 ['G@`e*\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &~6W!w
6、修复数据库 3BSJ|o<"=
ALTER DATABASE [dvbbs] SET SINGLE_USER &:}{?vU
GO j9bn|p$DA
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `<3/k
GO (b]r_|'
ALTER DATABASE [dvbbs] SET MULTI_USER /W vgC)
GO 5y1:oiE/
7、日志清除 ~zcHpxO^W
SET NOCOUNT ON NJe^5>4`
DECLARE @LogicalFileName sysname, #y?iUv
@MaxMinutes INT, -=+@/@nV
@NewSize INT !:N&tuJEv
USE tablename -- 要操作的数据库名 w7;,+Jq
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [Ju5O[o
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d=6FL" .o
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2brxV'tk
-- Setup / initialize l-} );zH74
DECLARE @OriginalSize int p1O[QQ|
SELECT @OriginalSize = size LRuB&4r8
FROM sysfiles ?FRuuAS
WHERE name = @LogicalFileName gXQ
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + kt0ma/QpP
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + j~'a %P
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "SV#e4C.
FROM sysfiles t}!Y}D
WHERE name = @LogicalFileName =MsQ=:ZV
CREATE TABLE DummyTrans ?Tr]zxtd
(DummyColumn char (8000) not null) P`HDQ/^O
DECLARE @Counter INT, -VOMt5u
@StartTime DATETIME, {Y(# <UDM
@TruncLog VARCHAR(255) ^`MGlI}
SELECT @StartTime = GETDATE(), S%sD#0l
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 5g$]ou
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /jtU<uX
EXEC (@TruncLog) t.ci!#/d
-- Wrap the log if necessary. FVgE^_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired V=?qU&r<+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName)
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AND (@OriginalSize * 8 /1024) > @NewSize z"vI-~,YU
BEGIN -- Outer loop. RdirEH*H
SELECT @Counter = 0 v95O)cC:W
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^qro0]"LD
BEGIN -- update =u.jZ*u]WT
INSERT DummyTrans VALUES ('Fill Log') lO>9Q]S<
DELETE DummyTrans zIeJ[J@
SELECT @Counter = @Counter + 1 k-zkb2
END =Ay'\j
EXEC (@TruncLog) }=fVO<Rv
END )v+R+3<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + \a}_=O
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *wd@YMOP
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^Fe%1Lnt
FROM sysfiles _Z>I"m
WHERE name = @LogicalFileName :CR1Oy 9
DROP TABLE DummyTrans O
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SET NOCOUNT OFF @N% /v*
8、说明:更改某个表 |RA|nu
exec sp_changeobjectowner 'tablename','dbo' z
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9、存储更改全部表 !=f$
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch R'Uw17I
@OldOwner as NVARCHAR(128), 0YApaL+jt
@NewOwner as NVARCHAR(128) 4L`<xX;:{
AS /KCJ)0UU
DECLARE @Name as NVARCHAR(128) 2l YA% n
DECLARE @Owner as NVARCHAR(128) t'.oty=
DECLARE @OwnerName as NVARCHAR(128) )}[:.Zg,3/
DECLARE curObject CURSOR FOR 2`ED?F68gH
select 'Name' = name, ' thEZ
'Owner' = user_name(uid) ]5_6m;g
from sysobjects - UMPt"o
where user_name(uid)=@OldOwner y. A]un1
order by name IcDAl~uG
OPEN curObject .vm.g=-q
FETCH NEXT FROM curObject INTO @Name, @Owner &|%F=/VU
WHILE(@@FETCH_STATUS=0) ~ ZN]2}
BEGIN AvxP0@.`
if @Owner=@OldOwner {Iu9%uR>@
begin (X(296<;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) TlA*~HG<Q
exec sp_changeobjectowner @OwnerName, @NewOwner $zR[2{bg
end Jm5&6=
-- select @name,@NewOwner,@OldOwner F-g7*
FETCH NEXT FROM curObject INTO @Name, @Owner `Qg#`
END D{J+}*y
close curObject G=Qslrtg
deallocate curObject vvDaL$
GO &E{i#r)'T
10、SQL SERVER中直接循环写入数据 \kQ@G
declare @i int [:MpOl-KIz
set @i=1 _Q
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while @i<30 rK@ UCRf
begin -$8M#n,
insert into test (userid) values(@i) I {o\d'/
set @i=@i+1 82q_"y>6
end MUs~ZF
小记存储过程中经常用到的本周,本月,本年函数 "V>7u{T
Dateadd(wk,datediff(wk,0,getdate()),-1) u>cU*E4/
Dateadd(wk,datediff(wk,0,getdate()),6) &M6cCT]&M
Dateadd(mm,datediff(mm,0,getdate()),0) J6s55
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) U_/<tWl\[3
Dateadd(yy,datediff(yy,0,getdate()),0) ju@5D
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #3L=\j[
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上面的SQL代码只是一个时间段 JuD$CHg;#
Dateadd(wk,datediff(wk,0,getdate()),-1) ` s}v6
Dateadd(wk,datediff(wk,0,getdate()),6) pR
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就是表示本周时间段. m&h5u,
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZYBK'&J4m
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7T)J{:+0!|
而在存储过程中 }&o*ZY-1
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) g3i !>
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9m:qQ1[\