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。 PQt")[
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一、基础 ;O5zUl-`
1、说明:创建数据库 Ty\R=y}}
CREATE DATABASE database-name ;C#F>SG\S
2、说明:删除数据库 HWAdhDZ
drop database dbname m@j?za9s
3、说明:备份sql server M^Yh|%M
--- 创建 备份数据的 device ja'T+!k
USE master CkC^'V)
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' uc{Ihw
--- 开始 备份 g/_5unI}u
BACKUP DATABASE pubs TO testBack !TH)
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4、说明:创建新表 XW H5d-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QZwNw;$k*
根据已有的表创建新表: hag$GX'2k
A:create table tab_new like tab_old (使用旧表创建新表) c]-<vkpV
B:create table tab_new as select col1,col2... from tab_old definition only Gu,wF(x7A
5、说明:删除新表 o[4}h:> dq
drop table tabname ,t744k')
6、说明:增加一个列 c]<5zyl"j1
Alter table tabname add column col type ztY}5A2`
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。 VCfl`Aq'l
7、说明:添加主键: Alter table tabname add primary key(col) s)t@ol
说明:删除主键: Alter table tabname drop primary key(col) M?49TOQA
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;d$rdFA_
删除索引:drop index idxname q q`4<0 I>
注:索引是不可更改的,想更改必须删除重新建。 octL"t8w
9、说明:创建视图:create view viewname as select statement bs&43Ae
删除视图:drop view viewname }K>d+6qk5
10、说明:几个简单的基本的sql语句 ?81c 4w
选择:select * from table1 where 范围 @{e}4s?7od
插入:insert into table1(field1,field2) values(value1,value2) ]q[D>6_
删除:delete from table1 where 范围 l'1pw
更新:update table1 set field1=value1 where 范围 ~/U1xk%
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! [aLI
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排序:select * from table1 order by field1,field2 [desc] @bLy,Xr&
总数:select count as totalcount from table1 B@))8.h]
求和:select sum(field1) as sumvalue from table1
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平均:select avg(field1) as avgvalue from table1 gg/-k;@ Rf
最大:select max(field1) as maxvalue from table1 iVr J Q
最小:select min(field1) as minvalue from table1 ^CH=O|8j
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11、说明:几个高级查询运算词 :Ov6_x]*
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A: UNION 运算符 B mb0cFQ
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 "{xrL4BtC
B: EXCEPT 运算符 {fM'6;ak
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ~=LE0. 3[
C: INTERSECT 运算符 W
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ) q4[zv9
注:使用运算词的几个查询结果行必须是一致的。 B-Hrex]
12、说明:使用外连接 #%2rP'He
A、left outer join: UDFDJm$
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。 R w\gTo
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 (,2SXV
B:right outer join: h"W,WxL8
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。 ]N]!o#q}L
C:full outer join: (mB&m@-N
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。 2pCaX\t
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二、提升 Yh7t"=o
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) KF}hV9IU
法一:select * into b from a where 1<>1 Dy&i&5E.-l
法二:select top 0 * into b from a = svN#q5s
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q<<v,ihh
insert into b(a, b, c) select d,e,f from b; wJqMa9|
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) {Xy5pfW
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 JR|ck=tq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >y>5#[M!
4、说明:子查询(表名1:a 表名2:b) HJH{nz'Lw
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) ejd(R+
5、说明:显示文章、提交人和最后回复时间 /nsX]V6i
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b pki%vRY
6、说明:外连接查询(表名1:a 表名2:b) r5/0u(\LB
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>Z<]s
7、说明:在线视图查询(表名1:a ) T::85
select * from (SELECT a,b,c FROM a) T where t.a > 1; \@zHON(
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 gJ{)-\
select * from table1 where time between time1 and time2 Fo_sgv8O<
select a,b,c, from table1 where a not between 数值1 and 数值2 ~?}Emn;t
9、说明:in 的使用方法 !<";cw(q
select * from table1 where a [not] in ('值1','值2','值4','值6') J;e2&gB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 C )
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0+ '&`Q!u
11、说明:四表联查问题: 5tkAFb4P
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 ..... $PPi5f}HD
12、说明:日程安排提前五分钟提醒 Zi
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Q&;9x? e
13、说明:一条sql 语句搞定数据库分页 ?V=ZIGj
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 (t|Zn@uY
14、说明:前10条记录 w9imKVry
select top 10 * form table1 where 范围 *^4"5X@
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) n>XdU%&
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) <lPG=Xt
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 JQI: sj
(select a from tableA ) except (select a from tableB) except (select a from tableC) q;CiV
17、说明:随机取出10条数据 A)!*]o>U
select top 10 * from tablename order by newid() x,-75
18、说明:随机选择记录 J@'wf8Ub
select newid() "S]TP$O D
19、说明:删除重复记录 jr."I+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 3
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20、说明:列出数据库里所有的表名 BWrxunHO
select name from sysobjects where type='U' BU_nh+dF
21、说明:列出表里的所有的 AT3Mlz~7#
select name from syscolumns where id=object_id('TableName') tNI^@xdim1
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。 8nJpp
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 dn3y\
显示结果: m(!FHPvN
type vender pcs cq]6XK-W
电脑 A 1 ~
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电脑 A 1 q9_OGd|P
光盘 B 2 "8MF_Gu):
光盘 A 2 o.!Dq7R
手机 B 3 M }D}K\)
手机 C 3 2ilQXy
23、说明:初始化表table1 vE?G7%,
TRUNCATE TABLE table1 HV|,}Wks6s
24、说明:选择从10到15的记录 r19
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc X"Swi&4
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三、技巧 ##*3bDf$-5
1、1=1,1=2的使用,在SQL语句组合时用的较多 R 9\*#c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3pKQ$\u
如: 6_Y,eL]"
if @strWhere !='' ~?BXti<!
begin ?tbrbkx
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere wHy!CP%
end :I#V.
else &QgR*,5eo
begin }}~ |!8
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' C'x&Py/#
end :o3N;*o>)0
我们可以直接写成 T~e.PP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |{ip T SH
2、收缩数据库 C6PdDRf
--重建索引 W6Fo6a"<
DBCC REINDEX V,njO{Q
DBCC INDEXDEFRAG 7.oM J
--收缩数据和日志 fHFE){
DBCC SHRINKDB y6a3tG
DBCC SHRINKFILE O0.*Pmt
3、压缩数据库 (9a^$C*
dbcc shrinkdatabase(dbname) %ET+iIhK
4、转移数据库给新用户以已存在用户权限 g7H(PF?
exec sp_change_users_login 'update_one','newname','oldname' 1qA;/-Zr<o
go {IjR^J=k
5、检查备份集 ]/v[8dS(l
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ygcm|PrS
6、修复数据库 MQ2}EY*A
ALTER DATABASE [dvbbs] SET SINGLE_USER upmx $H>
GO mfr|:i
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK y9ZvV0
GO !a\^Sk
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ALTER DATABASE [dvbbs] SET MULTI_USER 75lA%|
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GO N!}f}oF
7、日志清除 %N._w!N<5n
SET NOCOUNT ON 6gDN`e,@
DECLARE @LogicalFileName sysname, {Sh ;(.u^
@MaxMinutes INT, nw<uyaU-t
@NewSize INT ;uGv:$([g
USE tablename -- 要操作的数据库名 flx(HJK
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @6.vKCSE
@MaxMinutes = 10, -- Limit on time allowed to wrap log. LS[]=Mk@1
@NewSize = 1 -- 你想设定的日志文件的大小(M) h(DTa
-- Setup / initialize QT}tvm@PMq
DECLARE @OriginalSize int <P<z N~i9j
SELECT @OriginalSize = size 5^ Zg>I
FROM sysfiles ~W/z96'
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WHERE name = @LogicalFileName V7/Rby Q
SELECT 'Original Size of ' + db_name() + ' LOG is ' + [}m[ )L\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + gX@aG9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' UiNP3TJ'L
FROM sysfiles *T1_;4i
WHERE name = @LogicalFileName {!`6zBsP
CREATE TABLE DummyTrans uxz^/Gk
(DummyColumn char (8000) not null) Y]a@j!
DECLARE @Counter INT, %C]>9."
@StartTime DATETIME, !G|@6W`
@TruncLog VARCHAR(255) dO\"?aiD
SELECT @StartTime = GETDATE(), Z\sDUJ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]4e;RV-B
DBCC SHRINKFILE (@LogicalFileName, @NewSize) %yC,^
EXEC (@TruncLog) v$9y,^p@e
-- Wrap the log if necessary. |s_GlJV.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired DmcZta8n]
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1Y,Z
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AND (@OriginalSize * 8 /1024) > @NewSize yhJ@(tu.Gd
BEGIN -- Outer loop. :4|4 =mkr
SELECT @Counter = 0 !)$Zp\Sg
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `]aeI'[}R
BEGIN -- update rm_Nn8p,
INSERT DummyTrans VALUES ('Fill Log') wd6owr
DELETE DummyTrans &^nGtW%a 9
SELECT @Counter = @Counter + 1 vDvFL<`vmD
END nk:)j:fr
EXEC (@TruncLog) ,zc(t<|-y
END \M-OC5fQv
SELECT 'Final Size of ' + db_name() + ' LOG is ' + O/LXdz0B
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + `vV7c`K?
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !r-F>!~
FROM sysfiles Q2>gU#
WHERE name = @LogicalFileName 7HWmCaa[
DROP TABLE DummyTrans rN>R|].
SET NOCOUNT OFF *zLMpL_
8、说明:更改某个表 AQ Ojit6p
exec sp_changeobjectowner 'tablename','dbo' qQa}wcU'9p
9、存储更改全部表 :6dxtl/{b:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y{Q
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@OldOwner as NVARCHAR(128), I1J-)R+
@NewOwner as NVARCHAR(128) < %Y}R\s?
AS ,x $,l
DECLARE @Name as NVARCHAR(128) ^zr`;cJ+c
DECLARE @Owner as NVARCHAR(128) i30!}}N8
DECLARE @OwnerName as NVARCHAR(128) pCG}ZKa
DECLARE curObject CURSOR FOR wC*X4 '
select 'Name' = name, i/.6>4tE:
'Owner' = user_name(uid) UF|p';oom
from sysobjects m {}Lm)M
where user_name(uid)=@OldOwner 05R@7[GWq
order by name HOi`$vX}N
OPEN curObject - YBY[%jF>
FETCH NEXT FROM curObject INTO @Name, @Owner Wn6Sn{8W{
WHILE(@@FETCH_STATUS=0) 1;iUWU1@
BEGIN ry]l.@o;
if @Owner=@OldOwner {8etv:y
begin xD 7]C|8o
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /{2,zW
exec sp_changeobjectowner @OwnerName, @NewOwner kx CSs7J/
end a9Vi];
-- select @name,@NewOwner,@OldOwner rM SZ"
FETCH NEXT FROM curObject INTO @Name, @Owner iow"n$/
END 4Tc~b3\!Y
close curObject )%]J>&/0J
deallocate curObject i~72bMwsA
GO =pr7G+_u
10、SQL SERVER中直接循环写入数据 XP}<N&j
declare @i int A}w/OA97RO
set @i=1 ?A0)L27UE&
while @i<30 atzX;@"K
begin CGFDqCNr-
insert into test (userid) values(@i) @9:uqsL
set @i=@i+1 ]###w;
end 4e
小记存储过程中经常用到的本周,本月,本年函数 y>LBl]
Dateadd(wk,datediff(wk,0,getdate()),-1) @+DX.9
Dateadd(wk,datediff(wk,0,getdate()),6) ,)io5nZF
Dateadd(mm,datediff(mm,0,getdate()),0) 5twhm
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) F[MFx^sT{
Dateadd(yy,datediff(yy,0,getdate()),0) YZ7.1`8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) =lSNs
上面的SQL代码只是一个时间段 j1Ezf=N6`
Dateadd(wk,datediff(wk,0,getdate()),-1) ?4uL-z](V
Dateadd(wk,datediff(wk,0,getdate()),6) )gi9f1n`
就是表示本周时间段. d5 -qZ{W
下面的SQL的条件部分,就是查询时间段在本周范围内的: _Ey5n!0:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,z6~?6m
而在存储过程中 0`H#
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) |a@L}m
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) hGrdtsH?