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。 !&U75FpN}:
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一、基础 Jk.x^
1、说明:创建数据库 8r(Vz
CREATE DATABASE database-name lO@-*m$
2、说明:删除数据库 qZ<n\Mt
drop database dbname (u?s@/e:`/
3、说明:备份sql server 5 H._Q
--- 创建 备份数据的 device 6C$+D
USE master I gJu/{:y^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' o#FctM'Z
--- 开始 备份 #hBqgG:>
BACKUP DATABASE pubs TO testBack W8<QgpV*
4、说明:创建新表 ,.Gp_BI
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ir^d7CV,
根据已有的表创建新表: 'bfxQ76@sa
A:create table tab_new like tab_old (使用旧表创建新表) m0G"Aj
B:create table tab_new as select col1,col2... from tab_old definition only xbiprhdv
5、说明:删除新表 M.g2y &8
drop table tabname >Iij,J5i
6、说明:增加一个列 v8-szW).
Alter table tabname add column col type UB@(r86d
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 J.~@j;[2
7、说明:添加主键: Alter table tabname add primary key(col) }Z <I%GT
说明:删除主键: Alter table tabname drop primary key(col) 1^k}GXsWmE
8、说明:创建索引:create [unique] index idxname on tabname(col....) >D=X
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删除索引:drop index idxname T#&1q]P1F
注:索引是不可更改的,想更改必须删除重新建。 frbd{o
9、说明:创建视图:create view viewname as select statement #o&T$D5
删除视图:drop view viewname P.(UbF d'
10、说明:几个简单的基本的sql语句 n l5+#e*\
选择:select * from table1 where 范围 %\it4 r3
插入:insert into table1(field1,field2) values(value1,value2) u&y> '
删除:delete from table1 where 范围 -IIrrY
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更新:update table1 set field1=value1 where 范围 ^aaj=p:cV
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
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排序:select * from table1 order by field1,field2 [desc] -t_&H\_T
总数:select count as totalcount from table1 yc0
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求和:select sum(field1) as sumvalue from table1 ^(Gl$GC$Mu
平均:select avg(field1) as avgvalue from table1 -Ua5anzB
最大:select max(field1) as maxvalue from table1 WDNj7
最小:select min(field1) as minvalue from table1 fTmJDUv+
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11、说明:几个高级查询运算词 i(A`'V8GY
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A: UNION 运算符 `@Z$+
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 }r04*P(
B: EXCEPT 运算符 R1*&rjB
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 5!Er;e
C: INTERSECT 运算符 # l1*# Z
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ",YNphjAn
注:使用运算词的几个查询结果行必须是一致的。 qLBQ!>lR
12、说明:使用外连接 8Ogg(uS70'
A、left outer join: Ez
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 a[t"J*0
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c V xN!Ki=
B:right outer join: i@{b+5$
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。 #~Kno@
C:full outer join: 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。 C4E* q3[Y
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二、提升 E:}s6l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Njo.-k
法一:select * into b from a where 1<>1 L `2{H%J`
法二:select top 0 * into b from a uToi4]w"y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) )m-(- I
insert into b(a, b, c) select d,e,f from b; Z){fie4WM
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) iLdUus!
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 x+sSmW
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. C
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4、说明:子查询(表名1:a 表名2:b) KjA7x
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) w^~s4Q_>>
5、说明:显示文章、提交人和最后回复时间 __z/X"H
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b EhW@iYL
6、说明:外连接查询(表名1:a 表名2:b) }lk9|U#6*`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c pJ?y
7、说明:在线视图查询(表名1:a ) ]_>38f7h
select * from (SELECT a,b,c FROM a) T where t.a > 1; >U:-U"rA?
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 ;{m;CKHI
select * from table1 where time between time1 and time2 sVO|Ghy65
select a,b,c, from table1 where a not between 数值1 and 数值2 +MS*YpPW
9、说明:in 的使用方法 fN`Prs A
select * from table1 where a [not] in ('值1','值2','值4','值6') -6q7ze{@
10、说明:两张关联表,删除主表中已经在副表中没有的信息 BT:b&"AR[
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _J>Ik2EF
11、说明:四表联查问题: 7x*L 1>[`'
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 ..... 98}l`J=i
12、说明:日程安排提前五分钟提醒 ~LH).\V
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @&h_+|:-
13、说明:一条sql 语句搞定数据库分页 Q{hK+z`D
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 &Ai+t2
14、说明:前10条记录 zPvTRW~H\
select top 10 * form table1 where 范围 *E@as
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.) *eAt '
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) d.sn D)X
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 a/d8_(0
(select a from tableA ) except (select a from tableB) except (select a from tableC) F0xm%?
17、说明:随机取出10条数据 "t{D5{q|[k
select top 10 * from tablename order by newid() p=Qo92
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18、说明:随机选择记录 FN0<iL
select newid() *XXa9z
19、说明:删除重复记录 k%RQf0`T
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) WAr6Dv,8
20、说明:列出数据库里所有的表名 ohPXwp?]
select name from sysobjects where type='U' ++kVq$9@y
21、说明:列出表里的所有的 -z/>W+k
select name from syscolumns where id=object_id('TableName') xG%O^
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 c*8k _o,
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ?f6Fj
显示结果: _T^@,!&
type vender pcs G!GGT?J
电脑 A 1 B3u:D"t
电脑 A 1 ~\R+p~>
光盘 B 2 3k+46Wp
光盘 A 2 Mc|UD*Z
手机 B 3 LZPLz@=&]
手机 C 3 pr"q-S>E
23、说明:初始化表table1 w="
TRUNCATE TABLE table1 K?wo AuY
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ds+0y;vc
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三、技巧 BfvvJh_
1、1=1,1=2的使用,在SQL语句组合时用的较多 p6{8t}
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jivGkIj!8
如: O~bzTn
if @strWhere !='' v3/G.B@=
begin H+5N+AKb@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~EhM"go
end ,|R\ Z,s
else !uHVg(}
begin LwCf}4u"
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b;e*`f8T3c
end alQ:'K
我们可以直接写成 (d5kD#.N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7OZjLD{ID
2、收缩数据库 \H?r[]*c%
--重建索引 "Kn%|\YL@4
DBCC REINDEX [1`&\C_E
DBCC INDEXDEFRAG H|!|fo-Tx
--收缩数据和日志 pL'+sW
DBCC SHRINKDB OEgp!J
DBCC SHRINKFILE "\Nn,3qp
3、压缩数据库 G
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dbcc shrinkdatabase(dbname) NHzhGg]
4、转移数据库给新用户以已存在用户权限 IsiCHtY9
exec sp_change_users_login 'update_one','newname','oldname' X[iQ%Y$/n
go .{#J2}+[_}
5、检查备份集 20RI S j
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' RC]-9gd3Q
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER ^&8xfI6?
GO w`K=J!5y2g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK [Gb8o'
GO r`CsR0[
ALTER DATABASE [dvbbs] SET MULTI_USER OM7EmMa;
GO ~@Eu4ip)F
7、日志清除 Hk|wO:7Be
SET NOCOUNT ON g~$cnU
DECLARE @LogicalFileName sysname, GZqy.AE,
@MaxMinutes INT, xrl!$xE
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@NewSize INT b\Gw|?Rv
USE tablename -- 要操作的数据库名 DlbNW& V
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 w57D qG>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. L(qQ,1VY
@NewSize = 1 -- 你想设定的日志文件的大小(M) r5aOQ
-- Setup / initialize *U^7MU0
DECLARE @OriginalSize int Wi{ jC?2Q
SELECT @OriginalSize = size r(cd?sL96R
FROM sysfiles n[`FoY
WHERE name = @LogicalFileName /q >1X!Z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + UgZuEfEGve
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N(^
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ).1F0T
FROM sysfiles P>i[X0UnL
WHERE name = @LogicalFileName z7g=L@
CREATE TABLE DummyTrans ;sn]Blpq
(DummyColumn char (8000) not null) BO)Q$*G~JD
DECLARE @Counter INT, =6:>C9
@StartTime DATETIME, mXXU{IwUe
@TruncLog VARCHAR(255) +(3U_]Lu
SELECT @StartTime = GETDATE(), ^8eu+E.{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' i_6 Y6
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $UGX vCR
EXEC (@TruncLog) E;AOCbV*$
-- Wrap the log if necessary. m3E`kW|
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ijR,% qg
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (^).$g5Hg
AND (@OriginalSize * 8 /1024) > @NewSize e$ {Cf
BEGIN -- Outer loop. WvJidz?5
SELECT @Counter = 0 i j+)U`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) TY6Q;BTU
BEGIN -- update ?m>!P@
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INSERT DummyTrans VALUES ('Fill Log') Ga1(T$|H
DELETE DummyTrans -'mTSJ.}
SELECT @Counter = @Counter + 1 w5uOkz #
END B6#^a
EXEC (@TruncLog) eQqx0+-0c
END /I/gbmc)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + FH}2wO~ _
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + #XPY\n^k
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' _gl7Ma
FROM sysfiles &3_.k
WHERE name = @LogicalFileName [uD G;We=
DROP TABLE DummyTrans `}Z`aK
SET NOCOUNT OFF VHihC]ks,
8、说明:更改某个表 +1o4l i
exec sp_changeobjectowner 'tablename','dbo' qPG>0
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9、存储更改全部表 EAPjQA-B?
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Uop`)
@OldOwner as NVARCHAR(128), EYD24
@NewOwner as NVARCHAR(128) l" P3lKS
AS -.=:@H}r
DECLARE @Name as NVARCHAR(128) g`9`/
DECLARE @Owner as NVARCHAR(128) :[C"}mR1
DECLARE @OwnerName as NVARCHAR(128) dFVx*{6
DECLARE curObject CURSOR FOR 6A23H7
select 'Name' = name, Cl>{vSN
'Owner' = user_name(uid) j}fu|-
from sysobjects 9H#;i]t &
where user_name(uid)=@OldOwner J':x]_;
order by name o/~Rf1
OPEN curObject 3yw`%$d5
FETCH NEXT FROM curObject INTO @Name, @Owner t#BQB<GI
WHILE(@@FETCH_STATUS=0) UHT2a9rG
BEGIN O=E?m=FR"
if @Owner=@OldOwner ,z0~VS:g 8
begin wFX>y^ 1
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1@W*fVn
exec sp_changeobjectowner @OwnerName, @NewOwner vnS;T+NZSC
end sRkPXzK
-- select @name,@NewOwner,@OldOwner x=%wPVJ
FETCH NEXT FROM curObject INTO @Name, @Owner tEFbL~n
END > t~2
close curObject L }L"BY3$
deallocate curObject J,Rp&tavt:
GO RR9G$}WS(
10、SQL SERVER中直接循环写入数据 &A!?:?3%O
declare @i int xjK@Q1MJ
set @i=1 +ko-oZ7V
while @i<30
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begin |\3X7)^8D
insert into test (userid) values(@i) E,p4R%:$@1
set @i=@i+1 PyQ
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end /k O
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小记存储过程中经常用到的本周,本月,本年函数 0n-S%e5
Dateadd(wk,datediff(wk,0,getdate()),-1) !l5&