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。 X|]&K
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一、基础 X'[93
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1、说明:创建数据库 sX_6qKUH
CREATE DATABASE database-name a(cZ]`s]*
2、说明:删除数据库 JSO'. [N
drop database dbname Ujb7uho
3、说明:备份sql server luLt~A3H$
--- 创建 备份数据的 device Ew.a*[W''
USE master DVC<P}/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Y243mq-
--- 开始 备份 L{)*evBL
BACKUP DATABASE pubs TO testBack ]rAaErB';
4、说明:创建新表 N-C=O
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Vm6
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根据已有的表创建新表: R|tf}~u !x
A:create table tab_new like tab_old (使用旧表创建新表) Xh'_Vx{.j`
B:create table tab_new as select col1,col2... from tab_old definition only xi3
5、说明:删除新表 Zq[aC0%+
drop table tabname M$L ;-T
6、说明:增加一个列 [OTZ"XQLI
Alter table tabname add column col type )GgO=J:o
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 .MUoNk!
7、说明:添加主键: Alter table tabname add primary key(col) ..u2IdEu
说明:删除主键: Alter table tabname drop primary key(col) gFBMARxi
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7Qoy~=E
删除索引:drop index idxname
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注:索引是不可更改的,想更改必须删除重新建。 %v)m&VUi%
9、说明:创建视图:create view viewname as select statement Fke_ms=I^
删除视图:drop view viewname vdS)EIt
10、说明:几个简单的基本的sql语句 RxUABF8b
选择:select * from table1 where 范围 *.g@6IkAQ
插入:insert into table1(field1,field2) values(value1,value2) %p wpRD@
删除:delete from table1 where 范围 QVEGd"WvvO
更新:update table1 set field1=value1 where 范围 (}^Qo^Vr
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @-d0~.S
排序:select * from table1 order by field1,field2 [desc] )$Tcip`
总数:select count as totalcount from table1 XHX$Ur9
求和:select sum(field1) as sumvalue from table1 (A<'{J#5,
平均:select avg(field1) as avgvalue from table1 (bT3
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最大:select max(field1) as maxvalue from table1 iRwlK5(&
最小:select min(field1) as minvalue from table1 F@C^nX9
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11、说明:几个高级查询运算词 &i/QFO7y}
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A: UNION 运算符 %+Az
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 %BV2 q
B: EXCEPT 运算符 )'pc 1I
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ?A]@$
C: INTERSECT 运算符 >R&=mo~
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。 N7}Y\1-8
注:使用运算词的几个查询结果行必须是一致的。 6e%|.}U
12、说明:使用外连接 ]E8S`[Vn
A、left outer join: yEvuTgDv
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。 Gd=l{~
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 (txr%Z0E
B:right outer join: 9gS.G2
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。 B^{87YR
C:full outer join: J3;dRW
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。 F~qiNV
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二、提升 utJz e
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) gJn_Z7Mg J
法一:select * into b from a where 1<>1 'J0Erk8(
法二:select top 0 * into b from a ,:G3 Y
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kJy
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insert into b(a, b, c) select d,e,f from b; 71$MhPvd<
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) i*q!|^M
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 c2$&pZ
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. A&dNCB
4、说明:子查询(表名1:a 表名2:b) {1jywb
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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) #c2InwZV
5、说明:显示文章、提交人和最后回复时间 s3.,
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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 L.]mC !
6、说明:外连接查询(表名1:a 表名2:b) 9F*],#ng
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .JJ^w!|>#
7、说明:在线视图查询(表名1:a ) NbDfD3
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select * from (SELECT a,b,c FROM a) T where t.a > 1; G0u3*.
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 s</llJ$
select * from table1 where time between time1 and time2 K% Gbl#
select a,b,c, from table1 where a not between 数值1 and 数值2 'yq'J)
9、说明:in 的使用方法 I,0]> kx
select * from table1 where a [not] in ('值1','值2','值4','值6') &R'%OFi
10、说明:两张关联表,删除主表中已经在副表中没有的信息 TLkJZ4}?Q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /p&)bL
11、说明:四表联查问题: @|2}*_3\
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 ..... (ex^=fv
12、说明:日程安排提前五分钟提醒 guD?~-Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lQ}e"#<
13、说明:一条sql 语句搞定数据库分页 &dC #nw
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 @3UVl^T
14、说明:前10条记录 =XT'D@q~W
select top 10 * form table1 where 范围 wu2AhMGmw
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.) h/CF^0m"!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $_.m<
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 CCX!>k]
(select a from tableA ) except (select a from tableB) except (select a from tableC) )kE(%q:*P$
17、说明:随机取出10条数据 #=MQE
select top 10 * from tablename order by newid() h0N*hx
18、说明:随机选择记录 jJ' LM>e
select newid()
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19、说明:删除重复记录 @c8s<9I]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) tv_Cn
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20、说明:列出数据库里所有的表名 Q9~UL^bF
select name from sysobjects where type='U' JqDj)}fzX
21、说明:列出表里的所有的 K7x,>
select name from syscolumns where id=object_id('TableName') .%@=,+nqz
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。 oc2aE:>X
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 x%;Q
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显示结果: UJ0Dy` f
type vender pcs Qbc62 qFu!
电脑 A 1 L-ZJ[#D
电脑 A 1 EmDA\9~@R
光盘 B 2 mQ9%[U,
光盘 A 2 wFW2m
手机 B 3 Efb S*f5
手机 C 3 P7Th94
23、说明:初始化表table1 WAj26";M(
TRUNCATE TABLE table1 {,5=U@J
24、说明:选择从10到15的记录 '(/ZJ88JP
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,H3C\.%w\
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三、技巧 VesO/xG<
1、1=1,1=2的使用,在SQL语句组合时用的较多 o3;u*f0rWn
"where 1=1" 是表示选择全部 "where 1=2"全部不选, X-Sso9/q.
如: EO|r
if @strWhere !='' ))n7.pB9/
begin o(W|BD!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S|A?z)I
end ;z9(
else y> S.B/d
begin 3I_"vk
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 'DQp
end Q<L.!%vu}
我们可以直接写成
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6TE RQ
2、收缩数据库 ?=<vC
--重建索引 .P=uR8
DBCC REINDEX u.gh04{5
DBCC INDEXDEFRAG t|*PC
--收缩数据和日志 @o+T<}kW X
DBCC SHRINKDB F<?e79},`
DBCC SHRINKFILE iSxxy1R
3、压缩数据库 5eC5oX>
dbcc shrinkdatabase(dbname) AWLKve_
4、转移数据库给新用户以已存在用户权限 R]%ZqT{PS
exec sp_change_users_login 'update_one','newname','oldname' M* W=v
go #K7i<Bf
5、检查备份集 'f`~"@
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "F+
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6、修复数据库 *seKph+'c
ALTER DATABASE [dvbbs] SET SINGLE_USER qEE3x>&T]
GO `n:IXD5'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK @A6\v+ih
GO {e2 (
ALTER DATABASE [dvbbs] SET MULTI_USER J
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GO h*hV
7、日志清除 RlX;c!K
SET NOCOUNT ON -e%=Mpq.
DECLARE @LogicalFileName sysname, UD*#!H
@MaxMinutes INT, $B4}('&4FQ
@NewSize INT kq:,}fc;B
USE tablename -- 要操作的数据库名 !23W=N}82
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ja~b5Tf9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. bF'~&<c
@NewSize = 1 -- 你想设定的日志文件的大小(M) t1B0M4x9
-- Setup / initialize "yc/8{U
DECLARE @OriginalSize int ##u+[ !
SELECT @OriginalSize = size 5 v~Y>
FROM sysfiles ^lu)'z%6
WHERE name = @LogicalFileName 5d(A(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |.:O$/ Tt[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + a-Cp"pKlVY
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' P1
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FROM sysfiles 5S$HDO&
WHERE name = @LogicalFileName _89
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CREATE TABLE DummyTrans 5G){7]P+r"
(DummyColumn char (8000) not null) g$dL5N7
DECLARE @Counter INT, KN~E9oGs
@StartTime DATETIME, %8$JL=c
@TruncLog VARCHAR(255) .2
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SELECT @StartTime = GETDATE(), M)EKS
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' U3kf$nbV/J
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (L|SE4
EXEC (@TruncLog) FPMhHHM
-- Wrap the log if necessary. 7!oqn'#>A
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 2WE
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) PBn(k>=+
AND (@OriginalSize * 8 /1024) > @NewSize V.Xz
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BEGIN -- Outer loop. 8)"KPr63M
SELECT @Counter = 0 ,l;
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (:+IS
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BEGIN -- update r-N2*uYtu
INSERT DummyTrans VALUES ('Fill Log') s^V8FH
DELETE DummyTrans @dCu]0oNI
SELECT @Counter = @Counter + 1 jI;bVG
END
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EXEC (@TruncLog) >+vWtO2
END x0lX6
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + 1uV_C[:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Z(as@gjH
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <u2*(BM4
FROM sysfiles ~O1*]
WHERE name = @LogicalFileName =53LapTPJ
DROP TABLE DummyTrans j{U-=[$'
SET NOCOUNT OFF JEHV\=
8、说明:更改某个表 x;Gyo
exec sp_changeobjectowner 'tablename','dbo' {f^30Fw
9、存储更改全部表 n"FOCcTIs
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch -'}iK6
@OldOwner as NVARCHAR(128), =l7LEkR
@NewOwner as NVARCHAR(128) 3Vw%[+lY9
AS 7abq3OK+`
DECLARE @Name as NVARCHAR(128) *?K`T^LS
DECLARE @Owner as NVARCHAR(128) =JVRm
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DECLARE @OwnerName as NVARCHAR(128) )D[xY0Y~
DECLARE curObject CURSOR FOR :>3&"T.
select 'Name' = name, f2yv7t
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'Owner' = user_name(uid) v$tS2N2
from sysobjects ItaJgtsV
where user_name(uid)=@OldOwner dhVwS$O )
order by name (B$FX<K3
OPEN curObject +]
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FETCH NEXT FROM curObject INTO @Name, @Owner HJcZ~5jf
WHILE(@@FETCH_STATUS=0) (QRl
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BEGIN ]@8=e'V
if @Owner=@OldOwner vy#c(:UQR
begin ~IqT>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ;XtDz
exec sp_changeobjectowner @OwnerName, @NewOwner WX=+\`NyJ(
end d.}rn"(z
-- select @name,@NewOwner,@OldOwner KdR&OBm
FETCH NEXT FROM curObject INTO @Name, @Owner unX^ MPpw
END &&y@/<t
close curObject X_YD[
deallocate curObject =f|>7m.p
GO |1<Z3\+_/
10、SQL SERVER中直接循环写入数据 ~%}g"|o
declare @i int b,`\"'1
set @i=1 eS.]@E-T
while @i<30 @'rO=(-b
begin <n:?WP~U
insert into test (userid) values(@i) aLq;a
set @i=@i+1 +]e4c;`ko}
end 'H9~rq7
小记存储过程中经常用到的本周,本月,本年函数 b;O+QRa
Dateadd(wk,datediff(wk,0,getdate()),-1) nSC>x:jY5/
Dateadd(wk,datediff(wk,0,getdate()),6) n^%u9H
Dateadd(mm,datediff(mm,0,getdate()),0) ^\6UTnS.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) bc"N
Dateadd(yy,datediff(yy,0,getdate()),0) +OH."4Z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) P>kx{^
上面的SQL代码只是一个时间段 950b9Vn&
Dateadd(wk,datediff(wk,0,getdate()),-1) qXF"1f_+
Dateadd(wk,datediff(wk,0,getdate()),6) z? aDOh
就是表示本周时间段. Xm-63U`w5
下面的SQL的条件部分,就是查询时间段在本周范围内的: gi6_la+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) \*N1i`99
而在存储过程中 :W&\})
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) **"P A8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) p[eRK .$!