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。 st "@kHQ3
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一、基础 sOWP0xY
1、说明:创建数据库 av(qV$2
CREATE DATABASE database-name K6B6@
2、说明:删除数据库 EiM\`"o
drop database dbname N/{=j
3、说明:备份sql server 79)iv+nf\l
--- 创建 备份数据的 device rS\mFt X
USE master Iu~(SKr=|$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Z] cFbl\ma
--- 开始 备份 `ZC -lAY
BACKUP DATABASE pubs TO testBack u8A,f}D 3
4、说明:创建新表 T` v
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) t9W* N\
根据已有的表创建新表: O[1Q#
A:create table tab_new like tab_old (使用旧表创建新表) ?=iy 6q
B:create table tab_new as select col1,col2... from tab_old definition only gEVoY,}/-U
5、说明:删除新表 <4?(|Vh[m]
drop table tabname Us&~d"n
6、说明:增加一个列 !h1|B7N
Alter table tabname add column col type ?5d[BV
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。 bsc b
7、说明:添加主键: Alter table tabname add primary key(col) !C' Y
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说明:删除主键: Alter table tabname drop primary key(col) f]Z9=
8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname W}(xE?9&
注:索引是不可更改的,想更改必须删除重新建。 `a7b,d
9、说明:创建视图:create view viewname as select statement :oZ~&H5Q
删除视图:drop view viewname p_g8d&]V
10、说明:几个简单的基本的sql语句 i2O$oHd
选择:select * from table1 where 范围 bb/A}<
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插入:insert into table1(field1,field2) values(value1,value2) ,`ehR6b
删除:delete from table1 where 范围 =cR=E{20
更新:update table1 set field1=value1 where 范围 .0y .0=l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 5X-d,8{w
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排序:select * from table1 order by field1,field2 [desc] Q?m= a0g
总数:select count as totalcount from table1 d5LL(
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求和:select sum(field1) as sumvalue from table1 Z
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平均:select avg(field1) as avgvalue from table1 8+_e= _3R
最大:select max(field1) as maxvalue from table1 d{'u97GDc
最小:select min(field1) as minvalue from table1 J]*?_>"#8
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11、说明:几个高级查询运算词 a,*|*Cv
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A: UNION 运算符 +^aM(4K\
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 h4M>k{
B: EXCEPT 运算符 ?B4X&xf.D
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 }cy<$=c#E_
C: INTERSECT 运算符 _vE[TFy
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。 `~W ?a
注:使用运算词的几个查询结果行必须是一致的。 K&vqk/JW1
12、说明:使用外连接 DVyxe}
A、left outer join: \]t}N
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。 ~c
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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 +@C|u'
B:right outer join: qc^qCGy!z
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。 2`/p V0
C:full outer join: O:O
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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。 K06&.>v_
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二、提升 (=i+{
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _Nq7_iT0
法一:select * into b from a where 1<>1 Y)v_O_`
法二:select top 0 * into b from a 1|\/2
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) #v4q:&yKf
insert into b(a, b, c) select d,e,f from b; z2A1h!Me
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) M)CE%/P
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3/((7O[
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 'd
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4、说明:子查询(表名1:a 表名2:b) mo3HUXf}8
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) .EoLJHL
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5、说明:显示文章、提交人和最后回复时间 BIjQ8 t
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "*aL(R
6、说明:外连接查询(表名1:a 表名2:b) r$Ck:Q}
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c h/n&&J
7、说明:在线视图查询(表名1:a ) @5\ns-%
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9i+SU|;j
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 9AdA|/WV
select * from table1 where time between time1 and time2 J'>i3eLq
select a,b,c, from table1 where a not between 数值1 and 数值2 :vJ0Ypz-u
9、说明:in 的使用方法 RZ&T\;m,7
select * from table1 where a [not] in ('值1','值2','值4','值6') 07L1 "
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o=VDO,eS
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7Z<ba^r}
11、说明:四表联查问题: 6> Szxkz
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... >A;9Ee"&
12、说明:日程安排提前五分钟提醒 S>pbplE
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 =9JKg4I6
13、说明:一条sql 语句搞定数据库分页 5 J9,/M0
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 )9QeVf
14、说明:前10条记录 k9<P]%
select top 10 * form table1 where 范围 ]2P*Z6Az
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) L.@o
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .-g++f(_i
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 #{kwl|c
(select a from tableA ) except (select a from tableB) except (select a from tableC) |H'4];>R?
17、说明:随机取出10条数据 )tyhf(p6
select top 10 * from tablename order by newid() wd`lN,WiW
18、说明:随机选择记录 #A2)]XvY
select newid() jQiKof>
19、说明:删除重复记录 do1aH$Iw
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2=6}! Y
20、说明:列出数据库里所有的表名 IA XoEBlMs
select name from sysobjects where type='U' 80M"`6
21、说明:列出表里的所有的 6U`yf&D
select name from syscolumns where id=object_id('TableName') @dzO{)
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。 AI&Bv
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 T~rPpi&
显示结果: `'{>2d%\g
type vender pcs (0T6kD
电脑 A 1 (ft8,^=4
电脑 A 1 >wpC45n)9N
光盘 B 2 f|f9[h'
光盘 A 2 ,NQucp
手机 B 3 D|}%(N@sl
手机 C 3 b!R\ u1b
23、说明:初始化表table1 U
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TRUNCATE TABLE table1 Q~A25Jf.
24、说明:选择从10到15的记录 !V6O~#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc q >|:mXR
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三、技巧 F`$V H^%V
1、1=1,1=2的使用,在SQL语句组合时用的较多 $=iV)-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, wYrb P11
如: m|)Mc VV
if @strWhere !='' C[ ehw
begin I'h6!N"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 0P<bS?e<l
end +d0&(b
else L`$MOdF{_
begin #mNM5(o
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i%8I (F
end =W6AUN/%p
我们可以直接写成 RY(\/W#$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere y^#jM
2、收缩数据库 8#9di
--重建索引 L)5YX-?
DBCC REINDEX $\|$ekil4
DBCC INDEXDEFRAG p1
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--收缩数据和日志 F(- Q]xj,
DBCC SHRINKDB I&oHVFY+
DBCC SHRINKFILE 1Y"[Qs]"mU
3、压缩数据库 v(T;Y=&
dbcc shrinkdatabase(dbname) v(?^#C>6W
4、转移数据库给新用户以已存在用户权限 ,iXE3TN;W
exec sp_change_users_login 'update_one','newname','oldname' Cw<bu|?
go $DmWK_A
5、检查备份集 <Q06<{]R8
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 8$:4~:]/
6、修复数据库 /Ot=GhN]
ALTER DATABASE [dvbbs] SET SINGLE_USER u.t(78N
GO OKU9v{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8,BNs5
GO _y q"F#,*
ALTER DATABASE [dvbbs] SET MULTI_USER J
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GO >;N0( xB
7、日志清除 3le/(=&1
SET NOCOUNT ON Ng?n}$g*
DECLARE @LogicalFileName sysname, (%huWW
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@MaxMinutes INT, D6trqB
@NewSize INT {%(_Z`vI
USE tablename -- 要操作的数据库名 M+X>!Os
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `c^ _5:euX
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $d4^e&s
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]o<'T.x
-- Setup / initialize :*aBiX"
DECLARE @OriginalSize int xF'9`y^]!@
SELECT @OriginalSize = size FqOV/B
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FROM sysfiles Y|t] bb
WHERE name = @LogicalFileName OAu?F}O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + }LDH/#
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [-X=lJ:+h
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' aHosu=NK
FROM sysfiles Ctpr.
WHERE name = @LogicalFileName bDa(@QJ-
CREATE TABLE DummyTrans #{)=%5=c
(DummyColumn char (8000) not null) =}Np0UP
DECLARE @Counter INT, 3%?01$k
@StartTime DATETIME, wf!?'*
@TruncLog VARCHAR(255) ^zv0hGk 2
SELECT @StartTime = GETDATE(), ?lJm}0>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' KLW#+vZ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) HhN;&67~Z
EXEC (@TruncLog) w /$4
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-- Wrap the log if necessary. p/|]])2
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ozZW7dveU
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %oasIiO
AND (@OriginalSize * 8 /1024) > @NewSize 'u }|~u?m
BEGIN -- Outer loop. ;iJ*.wVq
SELECT @Counter = 0 F V8K_xj
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M),i4a?2
BEGIN -- update wu5]S)?*
INSERT DummyTrans VALUES ('Fill Log') a"^0;a
DELETE DummyTrans */iD68r|-
SELECT @Counter = @Counter + 1 ^EGe%Fq*x]
END P9~7GFas|
EXEC (@TruncLog) QMoh<[3qu
END bce>DLF
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $;1#gq%
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %./vh=5)
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' H]V@Q~?e
FROM sysfiles {VBx;A3*I
WHERE name = @LogicalFileName ?{W@TY@S
DROP TABLE DummyTrans 29DYL
SET NOCOUNT OFF gF(aYuk
8、说明:更改某个表 8A{n9>jrb
exec sp_changeobjectowner 'tablename','dbo' .CI {g2
9、存储更改全部表 D9
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8X":,s!
@OldOwner as NVARCHAR(128), JivkY"= F
@NewOwner as NVARCHAR(128) \_pP:e
AS 0|g|k7c{rF
DECLARE @Name as NVARCHAR(128) GAONgz|ZI
DECLARE @Owner as NVARCHAR(128) p._BG80
DECLARE @OwnerName as NVARCHAR(128) "'us.t.
DECLARE curObject CURSOR FOR CV% AqJN
select 'Name' = name, 1|)l6#hOL
'Owner' = user_name(uid) ig(a28%
from sysobjects J<h^V+x
where user_name(uid)=@OldOwner j(4BMk
order by name "
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OPEN curObject *oAv:8"iY
FETCH NEXT FROM curObject INTO @Name, @Owner 0 1U/{D6D
WHILE(@@FETCH_STATUS=0) ^&oa\7<'
BEGIN 5gnNgt~
if @Owner=@OldOwner ]J;pUH+u
begin X~ n=U4s}O
set @OwnerName = @OldOwner + '.' + rtrim(@Name) C8qA+dri
exec sp_changeobjectowner @OwnerName, @NewOwner 5)fEs.r0U
end <[O8{9j
-- select @name,@NewOwner,@OldOwner |7Fe~TC
FETCH NEXT FROM curObject INTO @Name, @Owner J;|r00M
END 7`;55Se
close curObject hGmJG,H
deallocate curObject (q'w"q j
GO -oo&8
10、SQL SERVER中直接循环写入数据 G+N&(:
declare @i int T
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set @i=1 mM.-MIp
while @i<30 %Q:i6 ~
begin X;Tayb
insert into test (userid) values(@i) N S*e<9
set @i=@i+1 mJT<
end ?bwF$Ku
小记存储过程中经常用到的本周,本月,本年函数 O,(p><k$/
Dateadd(wk,datediff(wk,0,getdate()),-1) t_HS0rxG
Dateadd(wk,datediff(wk,0,getdate()),6) .#zmX\a
Dateadd(mm,datediff(mm,0,getdate()),0) .v<c_~y
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) asT:/z0
Dateadd(yy,datediff(yy,0,getdate()),0) B{'x2I#,
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) N1rBpt
上面的SQL代码只是一个时间段 '<"eG!O
Dateadd(wk,datediff(wk,0,getdate()),-1) #g,JNJ}
Dateadd(wk,datediff(wk,0,getdate()),6) xQV5-VoFC
就是表示本周时间段. 40cgsRa|
下面的SQL的条件部分,就是查询时间段在本周范围内的: t]?u<KD<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) +JoE[;
而在存储过程中 ]m}<0-0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) jj^{^,z\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) >vE1,JD)w