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。 jBegh9KHq
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一、基础 ,3@#F/c3i~
1、说明:创建数据库 ) $PDo
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CREATE DATABASE database-name FJ asS8
2、说明:删除数据库 *Z|y'<s
drop database dbname Ei2'[PK
3、说明:备份sql server c%=IL M4
--- 创建 备份数据的 device qWmQ-|Py
USE master YW{C} NA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' dd]/.Z
--- 开始 备份 (\SA*.)
BACKUP DATABASE pubs TO testBack _q~=~nub
4、说明:创建新表 tKpmm`2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9<KAXr#
根据已有的表创建新表: 1Tu
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A:create table tab_new like tab_old (使用旧表创建新表) O%FPS=
B:create table tab_new as select col1,col2... from tab_old definition only S#+h$UVh
5、说明:删除新表 Th=eNL]
drop table tabname lV%N
6、说明:增加一个列 hiQha5
Alter table tabname add column col type 2Lx3=[ik
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。 aG^4BpIP
7、说明:添加主键: Alter table tabname add primary key(col) O }
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说明:删除主键: Alter table tabname drop primary key(col) ^MVkZ{gtre
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9/nn)soC3
删除索引:drop index idxname 0:+WO%z
注:索引是不可更改的,想更改必须删除重新建。 y- 1 pR
9、说明:创建视图:create view viewname as select statement j$+nKc$
删除视图:drop view viewname ^Vpq$'!
10、说明:几个简单的基本的sql语句 gvLf|+m
选择:select * from table1 where 范围 nw-I|PVTNa
插入:insert into table1(field1,field2) values(value1,value2) ]C) 4
删除:delete from table1 where 范围 J>\B`E
更新:update table1 set field1=value1 where 范围 92EWIHEWZ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Z?\2F%
排序:select * from table1 order by field1,field2 [desc] p\bDY
总数:select count as totalcount from table1 ~$~5qwl
求和:select sum(field1) as sumvalue from table1 utIX %0
平均:select avg(field1) as avgvalue from table1 Nqu>6^-z0
最大:select max(field1) as maxvalue from table1 }K&7%N4LZ
最小:select min(field1) as minvalue from table1 e d<n9R
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11、说明:几个高级查询运算词 o93`|yWl
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A: UNION 运算符 >(;{C<6|^
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。 /oriW;OF
B: EXCEPT 运算符 5F~'gLH/F-
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。 ~-I+9F
C: INTERSECT 运算符 %HL*c=
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。 2o'Wy
注:使用运算词的几个查询结果行必须是一致的。 _]Zs,Hy
12、说明:使用外连接 <N%7|t*eT
A、left outer join: #W|'1
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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。 R=|{n'n$0|
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c /AW=5Ck- #
B:right outer join: l?Ya"C`FL
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Z-l=\ekJ
C:full outer join: 8|" XSN
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 ;A*`e$
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二、提升 o|$AyS{1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) @~%r5pz6
法一:select * into b from a where 1<>1 kOed ]>H
法二:select top 0 * into b from a (JM5`XwM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 9o+)?1\
insert into b(a, b, c) select d,e,f from b; !7kG!)40
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) (_"*NY0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 T7#W0^tj
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 07[_.i.l
4、说明:子查询(表名1:a 表名2:b) =17t-
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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) D}mjN=Y
5、说明:显示文章、提交人和最后回复时间 *"{lMZ+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b C<P%CG&;
6、说明:外连接查询(表名1:a 表名2:b) 2Tagr1L
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }&[
7、说明:在线视图查询(表名1:a ) F~P%AjAx'
select * from (SELECT a,b,c FROM a) T where t.a > 1; GgB,tam{p
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 ?W)A
select * from table1 where time between time1 and time2 vMm1Z5S/
select a,b,c, from table1 where a not between 数值1 and 数值2 6E^.7%3
9、说明:in 的使用方法 |fHV2Y`:g
select * from table1 where a [not] in ('值1','值2','值4','值6') v+X)Qmzf~
10、说明:两张关联表,删除主表中已经在副表中没有的信息 6#HK'7ClL
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) m_)FC-/pSl
11、说明:四表联查问题: xjVS
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 ..... nYX@J6!
12、说明:日程安排提前五分钟提醒 Ipf=ZD
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;9c<K
13、说明:一条sql 语句搞定数据库分页 fyByz=pl
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 P3=W|81e
14、说明:前10条记录 ,=#F//
select top 10 * form table1 where 范围 BYMi6wts
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.) &8vCZN^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) < Pky9o;
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 MZT23[+
(select a from tableA ) except (select a from tableB) except (select a from tableC) 6Q${U7%7
17、说明:随机取出10条数据 ;oc&Hb
select top 10 * from tablename order by newid() =_:et0
18、说明:随机选择记录 =Xqc]5[i
select newid() IyWI5Q"t
19、说明:删除重复记录 ])nPPf
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Y4v|ko`l%
20、说明:列出数据库里所有的表名 rl#p".4q
select name from sysobjects where type='U' BBtzs^C|
21、说明:列出表里的所有的 3G(miP6
select name from syscolumns where id=object_id('TableName') ]{ntt}3G,
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。 50o~ P!Lz|
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 Uk6HQQ
显示结果: ~4 `5tb
type vender pcs U15H@h
电脑 A 1 uLWh|
电脑 A 1 Bq$rf < W
光盘 B 2 t({W
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光盘 A 2 &FF"nE*
手机 B 3 [rSR:V?"a
手机 C 3 \Ol kM<
23、说明:初始化表table1 _tYx~J2.Q
TRUNCATE TABLE table1 ;N0~;I
24、说明:选择从10到15的记录 yge,8i)c
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc /K.!sQ$
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三、技巧 [O?z@)dx
1、1=1,1=2的使用,在SQL语句组合时用的较多 5nKj
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, R5X.^u
如: BEre*J
if @strWhere !='' 1f":HnLRM
begin 3ZXQoC '
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere hMykf4
end TztAZ2C
else /(.mp<s0
begin sXD1C2o
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' p_${Nj
end =g|IG
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我们可以直接写成 n}!PO[m~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y7*U:I+N
2、收缩数据库 C<m{*C-`a
--重建索引 .P7"e5ge
DBCC REINDEX iqe%=%ZR
DBCC INDEXDEFRAG mqSQL}vR
--收缩数据和日志 ^h"`}[+
DBCC SHRINKDB ?'KL11@R
DBCC SHRINKFILE @NNq z
3、压缩数据库 SV~cJ]F
dbcc shrinkdatabase(dbname) q)^Jj?W
4、转移数据库给新用户以已存在用户权限 A m>cd;
exec sp_change_users_login 'update_one','newname','oldname' Fd[zDz
go jhb6T ?}
5、检查备份集 3%(N[&LU
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' id2j7|$,
6、修复数据库 F7O(Cy"1
ALTER DATABASE [dvbbs] SET SINGLE_USER i5CK*"$Q
GO CTZh0x
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK U qFv}VsnF
GO "saUai4z
ALTER DATABASE [dvbbs] SET MULTI_USER 6{^E{go
GO Is{KN!Hw
7、日志清除 5*,f
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SET NOCOUNT ON L 8dc(Z%v
DECLARE @LogicalFileName sysname, -6n K<e`
@MaxMinutes INT, ,I%g|'2
@NewSize INT +i@y@<l:+
USE tablename -- 要操作的数据库名 4 Dw@r{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 mg$]QnbAnH
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `CgaS#
@NewSize = 1 -- 你想设定的日志文件的大小(M) P dhEQ}H
-- Setup / initialize n8" .XS
DECLARE @OriginalSize int >VN5`Zlw\C
SELECT @OriginalSize = size BA%pY|"Q
FROM sysfiles '<ZlGFt'n
WHERE name = @LogicalFileName 'gPzm|f|t@
SELECT 'Original Size of ' + db_name() + ' LOG is ' + iX2]VRNx l
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 5yzv|mrx
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' gT#&"aP5S
FROM sysfiles 2&^]k`Aj6D
WHERE name = @LogicalFileName ihP|E,L=L
CREATE TABLE DummyTrans YW60q0:
(DummyColumn char (8000) not null) A8oo@z68n>
DECLARE @Counter INT, +gJ8{u!=k
@StartTime DATETIME, o!{w"K
@TruncLog VARCHAR(255) 2M68CE
SELECT @StartTime = GETDATE(), 7]||UuF<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 'Pn3%&O$
DBCC SHRINKFILE (@LogicalFileName, @NewSize) -8j+s}Q
EXEC (@TruncLog) ,u`YT%&L
-- Wrap the log if necessary. Od5JG .]
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired q(2K6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) AigS!-
AND (@OriginalSize * 8 /1024) > @NewSize S/ODqL|
BEGIN -- Outer loop. nysUZB
SELECT @Counter = 0 OVhE??#
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9/ibWa\.
BEGIN -- update r?Wk<>%>
INSERT DummyTrans VALUES ('Fill Log') .xH5fMj,"
DELETE DummyTrans 83Q4On
SELECT @Counter = @Counter + 1 (+FfB"3]
END GJtZ&H
EXEC (@TruncLog) &'}RrW-s
END 17G'jiYH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + TTt#a6eJ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *22nVKi{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' hR
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FROM sysfiles [5+}rwm&W
WHERE name = @LogicalFileName QUQu^p
DROP TABLE DummyTrans ~XWQhIAM4
SET NOCOUNT OFF pnbIiyV
8、说明:更改某个表 wT:b\km:!
exec sp_changeobjectowner 'tablename','dbo' Db1pW=66:
9、存储更改全部表 Xt@Z}B))pu
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch cxr=k%~}J
@OldOwner as NVARCHAR(128), N=QfP
@NewOwner as NVARCHAR(128) Y!gCMLL
AS b7wvaRe.
DECLARE @Name as NVARCHAR(128) 8F&=a,ps[
DECLARE @Owner as NVARCHAR(128) qIIv6''5@
DECLARE @OwnerName as NVARCHAR(128) h?8]C#6^
DECLARE curObject CURSOR FOR }9W4"e 2)
select 'Name' = name,
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'Owner' = user_name(uid) }#Qc \eud
from sysobjects Y#lk6
where user_name(uid)=@OldOwner 7U2J xE
order by name Ooq! 0g
OPEN curObject Bb}fj28
FETCH NEXT FROM curObject INTO @Name, @Owner A3iFI9Iv
WHILE(@@FETCH_STATUS=0) HFaj-~b
BEGIN "huFA|`
if @Owner=@OldOwner K3x.RQQ-
begin :X]itTrGs
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6DuEL=C
exec sp_changeobjectowner @OwnerName, @NewOwner KNLfp1!
end |>JS!NM
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-- select @name,@NewOwner,@OldOwner Wu_kx2h
FETCH NEXT FROM curObject INTO @Name, @Owner 9)gC6IiW
END :"IE
close curObject \8 h;K>=h
deallocate curObject eK!V
);
GO IuRmEL_Q_
10、SQL SERVER中直接循环写入数据 y10h#&k
declare @i int ~ y;6W0x
set @i=1 26k LhFS
while @i<30 FcYFovS
begin L>a
insert into test (userid) values(@i) V` 1/SQX
set @i=@i+1 q11>f
end tGl;@V@Qj
小记存储过程中经常用到的本周,本月,本年函数 3
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Dateadd(wk,datediff(wk,0,getdate()),-1) [>1OJY.S}T
Dateadd(wk,datediff(wk,0,getdate()),6) 2U:H545]]
Dateadd(mm,datediff(mm,0,getdate()),0) p-/|mL
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Y5FbU
Dateadd(yy,datediff(yy,0,getdate()),0) S&\L-@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .b-f9qc=
上面的SQL代码只是一个时间段 2m35R&
Dateadd(wk,datediff(wk,0,getdate()),-1) g;8jK8Kh
Dateadd(wk,datediff(wk,0,getdate()),6) }woo%N P
就是表示本周时间段. mA*AeP_$
下面的SQL的条件部分,就是查询时间段在本周范围内的: eZdu2.;<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) JZD[N Z<
而在存储过程中 =<X?sj5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .NvQm]N0.
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) g47-db"5