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。 e,vgD kI;
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一、基础 _58&^:/^
1、说明:创建数据库 Z1H
CREATE DATABASE database-name =w7k@[Bq
2、说明:删除数据库 <y-2ovw*
drop database dbname yj,+7[)
3、说明:备份sql server =aT8=ihP
--- 创建 备份数据的 device MMRO@MdfV
USE master #I yM`YB0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Ejf>QIB
--- 开始 备份 ku v<
BACKUP DATABASE pubs TO testBack +DT
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4、说明:创建新表 NnZ_x>R
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) :v-,-3AG
根据已有的表创建新表: mX
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A:create table tab_new like tab_old (使用旧表创建新表) ZCuh^
B:create table tab_new as select col1,col2... from tab_old definition only ng2yZ @$
5、说明:删除新表 %'F[(VB
drop table tabname >48)@sS
6、说明:增加一个列 kD+B8TrW
Alter table tabname add column col type $>~4RXC
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 9OF(UFgS
7、说明:添加主键: Alter table tabname add primary key(col) imS&N.*3m
说明:删除主键: Alter table tabname drop primary key(col) MM+nE_9lV
8、说明:创建索引:create [unique] index idxname on tabname(col....) o AS 'Z|
删除索引:drop index idxname 53^1;
注:索引是不可更改的,想更改必须删除重新建。 xI=[=;L
9、说明:创建视图:create view viewname as select statement #5kg3OO
删除视图:drop view viewname [aC2ktI
10、说明:几个简单的基本的sql语句 ~o;*{ Q
选择:select * from table1 where 范围 JENq?$S
插入:insert into table1(field1,field2) values(value1,value2) D2Kh+~l
删除:delete from table1 where 范围 `H;O! ty&d
更新:update table1 set field1=value1 where 范围 C"}]PW
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! VN4H+9E
排序:select * from table1 order by field1,field2 [desc] &
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总数:select count as totalcount from table1 vw
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求和:select sum(field1) as sumvalue from table1 ET ]`
平均:select avg(field1) as avgvalue from table1 47/YDy%
最大:select max(field1) as maxvalue from table1 A^7Y%
最小:select min(field1) as minvalue from table1 &_6B{Q
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11、说明:几个高级查询运算词 tdRnRoB
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A: UNION 运算符 +Y^/0=6h
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。 0/%VejZ'
B: EXCEPT 运算符 R75np^
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。 Yg7C"3;Vt
C: INTERSECT 运算符 XAr YmO
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。 r`'n3#O*
注:使用运算词的几个查询结果行必须是一致的。 *$7c||J7
12、说明:使用外连接
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A、left outer join: ?Da!QH
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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。 8BJ&"y8H
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 |a {*r.
B:right outer join: PT`gAUCw
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。 g*#.yC1/
C:full outer join: gTP0:
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。 q:v&wb%
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二、提升 aV8]?E5G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) AUAJMS!m
法一:select * into b from a where 1<>1 V5LzUg]
法二:select top 0 * into b from a M>g\Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) t7DT5SrR
insert into b(a, b, c) select d,e,f from b; "(d7:!%
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) -z4pI=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )Wm:Ilq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. DbkKmv&
4、说明:子查询(表名1:a 表名2:b) pEE.%U
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) F4Gv=q)Z
5、说明:显示文章、提交人和最后回复时间 '`Z5.<n7p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b MkG*6A
6、说明:外连接查询(表名1:a 表名2:b) Cc,,e`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c DPZG_{3D
7、说明:在线视图查询(表名1:a ) ',p`B-dw
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5zF7yvS.w
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 toCT5E_0=
select * from table1 where time between time1 and time2 *<_8]C0>
select a,b,c, from table1 where a not between 数值1 and 数值2 sk_Q\0a
9、说明:in 的使用方法 t/aT
select * from table1 where a [not] in ('值1','值2','值4','值6') Bq]eNq
10、说明:两张关联表,删除主表中已经在副表中没有的信息 +K%4jIm
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 3 tp'}v
11、说明:四表联查问题: B@Q Ate7
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 ..... 4`7:gfrO,
12、说明:日程安排提前五分钟提醒 u>.qhtm[
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 w+~s}ta2^
13、说明:一条sql 语句搞定数据库分页 %A dE5HI-
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 .pOTIRbA
14、说明:前10条记录 AA
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select top 10 * form table1 where 范围 hIPU%
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.) .5zqpm
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) V1j5jjck
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 qJN2\e2~f
(select a from tableA ) except (select a from tableB) except (select a from tableC) /r Hd9^Y
17、说明:随机取出10条数据 Hb;#aXHSd
select top 10 * from tablename order by newid() Q0_UBm^f
18、说明:随机选择记录 Vn6 g(:\w
select newid() j9YI6X"
19、说明:删除重复记录 viT/$7`AI
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) >I3#ALF
20、说明:列出数据库里所有的表名 {?
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select name from sysobjects where type='U' O&?i8XsB
21、说明:列出表里的所有的 O#E]a<N`
select name from syscolumns where id=object_id('TableName') /K"koV;
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 d[5?P?h')
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 8`*Wl;9u
显示结果: G.,dP+i
type vender pcs q]Cmaf (
电脑 A 1 @<tkwu
电脑 A 1 c6;tbL
光盘 B 2 a8Jn.!
光盘 A 2 ,tZWPF-
手机 B 3 Uzb~L_\Rmt
手机 C 3 jLf. qf8qm
23、说明:初始化表table1 &JM|u ww?1
TRUNCATE TABLE table1 LuB-9[^<
24、说明:选择从10到15的记录 /,z4tf
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc <$LVAy"RD
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三、技巧 R;gN^Yjk:
1、1=1,1=2的使用,在SQL语句组合时用的较多 PG8|w[V1 "
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 7Xi)[M?)#
如: {mK=Vi g
if @strWhere !='' ~1Q$FgLk
begin wG4=[d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere i*' 6"
end V_?5 cwZ
else 7c9-MP)
begin X/fk&Cp
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' F`;oe[wfk
end t/\J
我们可以直接写成 iXt >!f*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere gf^"sfNk
2、收缩数据库 NZSP*# !B
--重建索引 t8,s]I&
DBCC REINDEX y_:i'Ri.
DBCC INDEXDEFRAG E4aCL#}D
--收缩数据和日志 q/[)Z
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DBCC SHRINKDB QXnL(z
DBCC SHRINKFILE #`rvL6W q}
3、压缩数据库 mYf7?I~
dbcc shrinkdatabase(dbname) wIIxs_2Q0c
4、转移数据库给新用户以已存在用户权限 C d)j%
exec sp_change_users_login 'update_one','newname','oldname' G%w hOIFRq
go 0!YB.=\{_q
5、检查备份集 _4VF>#b
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "If]qX(w
6、修复数据库 gN|[n.W4
ALTER DATABASE [dvbbs] SET SINGLE_USER A"8`5qa
GO 9pD=E>4?#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK }u0t i"V
GO {%ZD^YSA
ALTER DATABASE [dvbbs] SET MULTI_USER }UK<tUO
GO JJ5s
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7、日志清除 UGK4uK+I`
SET NOCOUNT ON ^b=9{.5
DECLARE @LogicalFileName sysname, \J r ta
@MaxMinutes INT, @bQf =N+
@NewSize INT /(Se:jH$>
USE tablename -- 要操作的数据库名 %]Gm
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7RQ.oee
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `VT[YhO#}
@NewSize = 1 -- 你想设定的日志文件的大小(M) e$M \HPc
-- Setup / initialize K
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DECLARE @OriginalSize int ^fT|Wm<
SELECT @OriginalSize = size Ai&-W
FROM sysfiles *Y'@|xf*
WHERE name = @LogicalFileName :gMcl"t--
SELECT 'Original Size of ' + db_name() + ' LOG is ' + fGDR<t3yiQ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sf\p>gb
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' y#Je%tAe
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FROM sysfiles h0ufl.N_%
WHERE name = @LogicalFileName (a0q*iC%
CREATE TABLE DummyTrans C~IsYdln
(DummyColumn char (8000) not null) u6{=Z :
DECLARE @Counter INT, PMzPe"3M
@StartTime DATETIME, [hE0 9W
@TruncLog VARCHAR(255) kGsd3t!'
SELECT @StartTime = GETDATE(), hce *G@b
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \M-}(>Pfk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) x}t,v.:
EXEC (@TruncLog) #'N"<o[
-- Wrap the log if necessary. <QoSq'g#,=
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #gzY _)E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) IKx]?0sS
AND (@OriginalSize * 8 /1024) > @NewSize AvF:$kG
BEGIN -- Outer loop. M}|<#
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SELECT @Counter = 0 ;Ll/rJ:*
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) G j^J pG
BEGIN -- update !iBe/yb
INSERT DummyTrans VALUES ('Fill Log') Sq"O<FmI
DELETE DummyTrans *5'U3py
SELECT @Counter = @Counter + 1 [EUp4%Z #
END fG2hCP+
EXEC (@TruncLog) B2\R#&X.
END #flOaRl.
SELECT 'Final Size of ' + db_name() + ' LOG is ' + O(U'G|
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ZSCZt&2v
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' tJ>|t hk
FROM sysfiles jU\vg;nr
WHERE name = @LogicalFileName ?;Ck]l#5ys
DROP TABLE DummyTrans +cS%b}O`$
SET NOCOUNT OFF Uf#.b2]
8、说明:更改某个表 UV}\#86!
exec sp_changeobjectowner 'tablename','dbo' ,f
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9、存储更改全部表 &VG|*&M
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0Q^ -d+!
@OldOwner as NVARCHAR(128), dLb9p"EE#
@NewOwner as NVARCHAR(128) PMER~}^
AS Y0`@$d&n
DECLARE @Name as NVARCHAR(128) OU&eswW
DECLARE @Owner as NVARCHAR(128) 7#K%Bo2pG
DECLARE @OwnerName as NVARCHAR(128) wLyQ <[$
DECLARE curObject CURSOR FOR !;'#fxW[
select 'Name' = name, @Sb 86Ee
'Owner' = user_name(uid)
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from sysobjects d1YE$
where user_name(uid)=@OldOwner *7: )k
order by name bvY'=
OPEN curObject jb~2f2vUa
FETCH NEXT FROM curObject INTO @Name, @Owner $2u^z=`b!%
WHILE(@@FETCH_STATUS=0) HP T{83
BEGIN i[obQx S94
if @Owner=@OldOwner ?;1^8 c0
begin t?JY@hT*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) )c
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exec sp_changeobjectowner @OwnerName, @NewOwner M{ #
end LgN\%5f-
-- select @name,@NewOwner,@OldOwner {k.Dy92
FETCH NEXT FROM curObject INTO @Name, @Owner >iefEv\
END x8H%88!j*
close curObject 3QlV,)}
deallocate curObject 7O6VnKl
GO Z|&Y1k-h
10、SQL SERVER中直接循环写入数据 bo^d!/;
declare @i int %YjZF[P
set @i=1 cR.[4rG'
while @i<30 F0,-7<G
begin N<bNJD}
insert into test (userid) values(@i) *LnY}#
set @i=@i+1 ?@W=bJ8{
end L@> +iZSO
小记存储过程中经常用到的本周,本月,本年函数 A#&Q(g\YE
Dateadd(wk,datediff(wk,0,getdate()),-1) ="fq.Tt
Dateadd(wk,datediff(wk,0,getdate()),6) &^WJ:BvA|^
Dateadd(mm,datediff(mm,0,getdate()),0) )U4h?J
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Q}#5mf&cD
Dateadd(yy,datediff(yy,0,getdate()),0) VT.BHZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~I^}'^Dbb
上面的SQL代码只是一个时间段 1o5DQ'~n
Dateadd(wk,datediff(wk,0,getdate()),-1) 9y/gWE
Dateadd(wk,datediff(wk,0,getdate()),6) 1]eh0H
就是表示本周时间段. ;DWtCtD
下面的SQL的条件部分,就是查询时间段在本周范围内的: \@]/ks=K
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9$0-UUCk
而在存储过程中 c-S_{~~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Sb_T _m
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) nv WTx4oy