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。 'A#F< x
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一、基础 7Un5Y[FZo
1、说明:创建数据库 gukKa
CREATE DATABASE database-name ewp&QH4
2、说明:删除数据库 ff.;6R\
drop database dbname Kf'oXCs
3、说明:备份sql server |(O _K(
--- 创建 备份数据的 device }pL#C
USE master +!)v=NY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' .lIkJQ3d
--- 开始 备份 -KFozwr5/
BACKUP DATABASE pubs TO testBack ^V;2v? O
4、说明:创建新表 &/tGT3)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Bd-@@d.H<
根据已有的表创建新表: DXc3u^
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A:create table tab_new like tab_old (使用旧表创建新表) =#sr4T
B:create table tab_new as select col1,col2... from tab_old definition only }='1<~0
5、说明:删除新表 tP]-u3
drop table tabname l[Rl:k!
6、说明:增加一个列 =r1@?x
Alter table tabname add column col type KI~M.2pk
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。 pv){R;f
7、说明:添加主键: Alter table tabname add primary key(col) Q
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说明:删除主键: Alter table tabname drop primary key(col) ~x 0x.-^A
8、说明:创建索引:create [unique] index idxname on tabname(col....) kPg| o3H
删除索引:drop index idxname ={gf x;
注:索引是不可更改的,想更改必须删除重新建。 sqP (1|9
9、说明:创建视图:create view viewname as select statement ?Z[`sm
删除视图:drop view viewname mu#
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10、说明:几个简单的基本的sql语句 v35=4>Y
选择:select * from table1 where 范围 IW-lC{hK
插入:insert into table1(field1,field2) values(value1,value2) 1Wy0#?L
删除:delete from table1 where 范围 y7WO:X&
更新:update table1 set field1=value1 where 范围 qZ|>{^a*
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! GI$7uR}
排序:select * from table1 order by field1,field2 [desc] ^E349c-|
总数:select count as totalcount from table1 -=CZhp
求和:select sum(field1) as sumvalue from table1 ilpP"B
平均:select avg(field1) as avgvalue from table1 u AmDXqJ3
最大:select max(field1) as maxvalue from table1 vS_Ji<W~E
最小:select min(field1) as minvalue from table1 }*s%|!{H
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11、说明:几个高级查询运算词 K:\db'``
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A: UNION 运算符 `$N()P
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。 JXA!l?%
B: EXCEPT 运算符 m0zbG1OE
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。 8%W(",nd
C: INTERSECT 运算符 {, `)
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。 ^a+H`RD
注:使用运算词的几个查询结果行必须是一致的。 1so9w89
12、说明:使用外连接 ? <"H Io
A、left outer join: Q"2J2211
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。 krI@N}OU
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 r[}5<S Q
B:right outer join: OX!<{9o
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。 ]= nM|e
C:full outer join: w%L::Z4
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。 0M_~@E*&
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二、提升 9C_Vb39::$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?1kXV n$
法一:select * into b from a where 1<>1 g4-UBDtYt
法二:select top 0 * into b from a "q,.O5q}Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) { *&Wc Os
insert into b(a, b, c) select d,e,f from b; C0> Z<z
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) !:<(p
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ]
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. DN%b!K:
4、说明:子查询(表名1:a 表名2:b) /+g9C(['
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) @G&2Tbj[`
5、说明:显示文章、提交人和最后回复时间 pDloew
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `1fNB1c
6、说明:外连接查询(表名1:a 表名2:b) xh) h#p.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $pLJtQ
7、说明:在线视图查询(表名1:a ) 4u.Fy<+@4M
select * from (SELECT a,b,c FROM a) T where t.a > 1; E[8R
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Pv#>j\OR&
select * from table1 where time between time1 and time2 cU
select a,b,c, from table1 where a not between 数值1 and 数值2 7i@vj7K
9、说明:in 的使用方法 41Nm+$m
select * from table1 where a [not] in ('值1','值2','值4','值6') BV@xE
10、说明:两张关联表,删除主表中已经在副表中没有的信息 lCAD $Ia~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #i1z&b#@
11、说明:四表联查问题: .WV5Gf)
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 ..... 2iV/?.<Z&
12、说明:日程安排提前五分钟提醒 |h6u%t2AY
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 )' 3V4Z&
13、说明:一条sql 语句搞定数据库分页 1@"os[9
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 xb22:
14、说明:前10条记录 Fk*C8
select top 10 * form table1 where 范围 2k]Jkd,E
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.) 5dXDL~/2p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) |[B JZ
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 |JVp(Kx
(select a from tableA ) except (select a from tableB) except (select a from tableC) $FM:8^
17、说明:随机取出10条数据 C>gC99
select top 10 * from tablename order by newid() (S)jV0
18、说明:随机选择记录 YM<F7tp4
select newid() XKQ\Ts2<k
19、说明:删除重复记录 W0qn$H
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (BG
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20、说明:列出数据库里所有的表名 XRx^4]c
select name from sysobjects where type='U' I/`\>Hk
21、说明:列出表里的所有的 u`~,`z^{n
select name from syscolumns where id=object_id('TableName') )~LqBh
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。 z\zqmW6
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[=teB v<
显示结果: ;cD&qheDV
type vender pcs fB"It~ p
电脑 A 1 CjT]!D)s
电脑 A 1 <[Y@<
光盘 B 2 H5X.CcI&}
光盘 A 2 dR@XwEpP
手机 B 3 8d|#W
手机 C 3 >'g>CD!
23、说明:初始化表table1 >V|KS(}s
TRUNCATE TABLE table1 h'|J$
24、说明:选择从10到15的记录 ;9"6g=q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >m'n#=yap
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三、技巧 hreG5g9{
1、1=1,1=2的使用,在SQL语句组合时用的较多 ee\xj$,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, t^5xq8w8
如: *h4x`luJ
if @strWhere !='' d6vls7J/4
begin _sX@BE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere k?VH4yA
end ipH'}~=ID
else W0;MGBfb
begin LnlDCbF;!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' * G0I2
end 7?W1i{(
我们可以直接写成 F7lzc)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "Kc1@EX=
2、收缩数据库 :{'%I#k2
--重建索引 =QJI_veUG`
DBCC REINDEX ;+(EmD:Q
DBCC INDEXDEFRAG JSu+/rI1
--收缩数据和日志 y|2y!&o,!
DBCC SHRINKDB !63]t?QXMG
DBCC SHRINKFILE ]aI
3、压缩数据库 zya2 O?s
dbcc shrinkdatabase(dbname) kH" >(f
4、转移数据库给新用户以已存在用户权限 cTu"Tu\Qw
exec sp_change_users_login 'update_one','newname','oldname' 9?.
go r31)Ed$
5、检查备份集 u)9YRMl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' kmu r={IR
6、修复数据库 C|-QU
ALTER DATABASE [dvbbs] SET SINGLE_USER 2!Sl!x+i\'
GO H-/w8_} KG
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK K(75)/
GO N"-U)d-.
ALTER DATABASE [dvbbs] SET MULTI_USER 'v 0(ki#
GO m
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7、日志清除 YF68Ax]
SET NOCOUNT ON RZbiiMC>
DECLARE @LogicalFileName sysname, &b9bb{y_$K
@MaxMinutes INT, F/w*[Xi
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@NewSize INT B'8T+qvA
USE tablename -- 要操作的数据库名 |h^]`= 3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 'h3yxf}\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. a2SXg A
@NewSize = 1 -- 你想设定的日志文件的大小(M) <Wa7$ h F
-- Setup / initialize K %.>o
DECLARE @OriginalSize int 6S&OE k
SELECT @OriginalSize = size 3F?_{A
FROM sysfiles E@CK.-N|
WHERE name = @LogicalFileName nl+8C}=u
SELECT 'Original Size of ' + db_name() + ' LOG is ' + `L7Cf&W\l8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + f?W" ^6Df
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^k5# {?I
FROM sysfiles W,bu=2K6
WHERE name = @LogicalFileName Tu&W7aoX5
CREATE TABLE DummyTrans $VnPs!a
(DummyColumn char (8000) not null) ?L+|b5RS
DECLARE @Counter INT, {VT**o
@StartTime DATETIME, a+,zXJQYq
@TruncLog VARCHAR(255) Hd89./v`:
SELECT @StartTime = GETDATE(), \W+Hzf]
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3_N1y
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /amWf^z
EXEC (@TruncLog) 0s.X
-- Wrap the log if necessary. Xz\ X 8I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8)XAdAr
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) KSQ*HO)5
AND (@OriginalSize * 8 /1024) > @NewSize Zy=DY
BEGIN -- Outer loop. e`bP=7`0
SELECT @Counter = 0 nQ08(8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) t`pbEjE0K
BEGIN -- update |u_fVQj
INSERT DummyTrans VALUES ('Fill Log') L!0}&i;u~5
DELETE DummyTrans CG]/.
SELECT @Counter = @Counter + 1 EpB3s{B"
END y1#*c$ O
EXEC (@TruncLog) O PJ(ub
END VU;98
SELECT 'Final Size of ' + db_name() + ' LOG is ' + C=8IQl[^e
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + u-@;Q<v$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ih(A l<IS
FROM sysfiles vf?Xt
WHERE name = @LogicalFileName I|.
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DROP TABLE DummyTrans 9v?rNJs
SET NOCOUNT OFF b]g#mQ
8、说明:更改某个表 :4[_&]H
exec sp_changeobjectowner 'tablename','dbo' FXh*!%"*
9、存储更改全部表 ZDx1v_xr
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch d"OYq
@OldOwner as NVARCHAR(128), GC7W7B
@NewOwner as NVARCHAR(128) o ]@'R<F(u
AS g"v6UZ\
DECLARE @Name as NVARCHAR(128) R{UZCFZ
DECLARE @Owner as NVARCHAR(128) 5#mHWBGd7
DECLARE @OwnerName as NVARCHAR(128) A@jBn6
DECLARE curObject CURSOR FOR ta0 ;:o?/d
select 'Name' = name, &Xh=bM'/%m
'Owner' = user_name(uid) ;E0x#JUrw
from sysobjects : eFyd`Syw
where user_name(uid)=@OldOwner m'WGK`WIm
order by name `$XgfMBf |
OPEN curObject ?KG4Z
FETCH NEXT FROM curObject INTO @Name, @Owner 6\USeZh
WHILE(@@FETCH_STATUS=0) TGuCIc0B{
BEGIN *0Wkz'=U
if @Owner=@OldOwner `a5,5}7v%`
begin u3\_![Jt?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) _7<G6q2(
exec sp_changeobjectowner @OwnerName, @NewOwner 3{M0iNc1
end &Z%'xAOGR
-- select @name,@NewOwner,@OldOwner X0 ]Se(
FETCH NEXT FROM curObject INTO @Name, @Owner \_ MWZRMc5
END 7>f)pfLM
close curObject vHN/~k#
deallocate curObject K0\`0E^,
GO
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10、SQL SERVER中直接循环写入数据 _ygdv\^Tet
declare @i int \`W8#fob
set @i=1 .&.L@CRH
while @i<30 74a k|(!
begin e#@u&+K/f
insert into test (userid) values(@i) RmQ>.?
set @i=@i+1 /w2NO9Q
end {BZ0x2
小记存储过程中经常用到的本周,本月,本年函数 rEoOv
Dateadd(wk,datediff(wk,0,getdate()),-1) g{JH5IZ~
Dateadd(wk,datediff(wk,0,getdate()),6) w:2yFC
Dateadd(mm,datediff(mm,0,getdate()),0) = Q"(9[Az
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n/^QPR$>.
Dateadd(yy,datediff(yy,0,getdate()),0) H>wXQ5 ?W;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) o3HS|
上面的SQL代码只是一个时间段 S"/gZfxer
Dateadd(wk,datediff(wk,0,getdate()),-1) orhzeOi\
Dateadd(wk,datediff(wk,0,getdate()),6) tD])&0"(
就是表示本周时间段. ~zDFL15w
下面的SQL的条件部分,就是查询时间段在本周范围内的: k[\JT[Mp
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) sI@kS^
而在存储过程中 H%;pPkIi
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (, $Lp0mB7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =cxG4R1x