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。 >D<nfG<s Z
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一、基础 /=[M
1、说明:创建数据库 BQ_\8Qt|
CREATE DATABASE database-name 7{az %I$h
2、说明:删除数据库 sy/J+==
drop database dbname YJeZ{Wws
3、说明:备份sql server nGX~G^mZ
--- 创建 备份数据的 device _Y\@{T;^Zb
USE master $@8\9Y
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' l]3g6c
--- 开始 备份 :M|bw{P*
BACKUP DATABASE pubs TO testBack ^b>E_u
4、说明:创建新表 pPG!{:YT
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SuGlNp>#qm
根据已有的表创建新表: A(;J
A:create table tab_new like tab_old (使用旧表创建新表) d'Gv \i&e
B:create table tab_new as select col1,col2... from tab_old definition only 69yTGUG3
5、说明:删除新表 '{6`n5:e
drop table tabname Wu.od|t0
6、说明:增加一个列 %z8@;
Alter table tabname add column col type T7cT4PAW
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 \mWXr*;
7、说明:添加主键: Alter table tabname add primary key(col) S)JZb_
说明:删除主键: Alter table tabname drop primary key(col) jcx/ZR
8、说明:创建索引:create [unique] index idxname on tabname(col....) >`,v?<>+
删除索引:drop index idxname !j YV,:'
注:索引是不可更改的,想更改必须删除重新建。 <uv{/L
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9、说明:创建视图:create view viewname as select statement \UtUP#Y{t
删除视图:drop view viewname uVOpg]8d
10、说明:几个简单的基本的sql语句 ZpI _/
选择:select * from table1 where 范围 ,u~\$Az6
插入:insert into table1(field1,field2) values(value1,value2) Vy-S9=
删除:delete from table1 where 范围 P]dDTh~e~
更新:update table1 set field1=value1 where 范围 iP'}eQn]c
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {fIH9+v
排序:select * from table1 order by field1,field2 [desc] UPN2p&gM
总数:select count as totalcount from table1 ;}|.crMF
求和:select sum(field1) as sumvalue from table1 aoF>{Z4&B
平均:select avg(field1) as avgvalue from table1 [k."R@?
最大:select max(field1) as maxvalue from table1 u$<FKp;I
最小:select min(field1) as minvalue from table1 `yuD/-j
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11、说明:几个高级查询运算词 #docBsHX&s
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A: UNION 运算符 6LvUi|~"<
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。 y=
B: EXCEPT 运算符 &Lq @af#
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。 O]{H2&k@
C: INTERSECT 运算符 X8;03EW;
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。 unD8h=Z2
注:使用运算词的几个查询结果行必须是一致的。 o/=K:5
12、说明:使用外连接 $I1p"6
A、left outer join: Hyee#fB
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。 ?{{E/J:%
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 $RA"NIZ:!
B:right outer join: ]]d@jj
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。 {'r(P&
C:full outer join: JmN;v|wF:c
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。 _MMz x2}
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二、提升 \N"K^kR4
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) rt~X(S
法一:select * into b from a where 1<>1 pF"z)E|^
法二:select top 0 * into b from a by8d18:it
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) xYwbbFGrG
insert into b(a, b, c) select d,e,f from b; Y6{p|F?&"
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) jh8%Xu]t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Eda
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \19XDqf8
4、说明:子查询(表名1:a 表名2:b) nMVThN*Ig
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&Q
5、说明:显示文章、提交人和最后回复时间 n,Ux>L
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b e,1Jxz4QH
6、说明:外连接查询(表名1:a 表名2:b) T6phD8#
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Kh% x
7、说明:在线视图查询(表名1:a ) bk^ :6>{K
select * from (SELECT a,b,c FROM a) T where t.a > 1; aty
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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 'u696ED4
select * from table1 where time between time1 and time2 +m>Kb edl
select a,b,c, from table1 where a not between 数值1 and 数值2 GD< Afni
9、说明:in 的使用方法 $L`7(0U-
select * from table1 where a [not] in ('值1','值2','值4','值6') bWMM[pnL
10、说明:两张关联表,删除主表中已经在副表中没有的信息 typ*.j[q
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %o{vD&7\
11、说明:四表联查问题: < W&~tVv
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 ..... (iWNvVGS
12、说明:日程安排提前五分钟提醒 W:EXL@
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n\cP17dr
13、说明:一条sql 语句搞定数据库分页 88G[XkL$2
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 Pv/P<i^
14、说明:前10条记录 AKAAb~{
select top 10 * form table1 where 范围 0/] @#G2
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.) 7r}gS2d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) \t!+]v8f8
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 3:=XU9p)x
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?58pkg J
17、说明:随机取出10条数据 CQtd%'rt6
select top 10 * from tablename order by newid() 9sT?"(=
18、说明:随机选择记录 Wa[~)A
select newid() SXod r}
19、说明:删除重复记录 +9h6{&yr1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) i
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20、说明:列出数据库里所有的表名 $B$=,^)3
select name from sysobjects where type='U' XUSfOf(
21、说明:列出表里的所有的 <F=j6U7
select name from syscolumns where id=object_id('TableName') b0KorUr
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。 ^k-H$]
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type _Yh4[TT~/
显示结果: 5h20\b?=$
type vender pcs /n"A%6S
电脑 A 1 J v)]7u
电脑 A 1 (.n"
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光盘 B 2 _$=xa6YA
光盘 A 2 wkd591d*
手机 B 3 Fg,[=CqB[
手机 C 3 ;G},xDGO_m
23、说明:初始化表table1 Ap97 Zcw
TRUNCATE TABLE table1 ZFdQZ=.'
24、说明:选择从10到15的记录 gV`:eNo*
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc VVe>}
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三、技巧 Bj]0Cz
1、1=1,1=2的使用,在SQL语句组合时用的较多 LRbevpZ,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, WO}JIExy
如: \8t g7Sdq
if @strWhere !='' qC3 rHT]
begin O-&n5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere pP".?|n
end iK.MC%8?
else Dt+"E
begin kYR&t}jlCg
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' j+c)%
end PN.=])7T
我们可以直接写成 2{#quXN9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ' !_44
2、收缩数据库 U}qW9X;o
--重建索引 M_XZOlW5
DBCC REINDEX !-;Me&"I=`
DBCC INDEXDEFRAG h.7 1O"N
--收缩数据和日志
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DBCC SHRINKDB +h9CcBd
DBCC SHRINKFILE Ak9W8Z}
3、压缩数据库 U2Ur N?T
dbcc shrinkdatabase(dbname) )FHaJ*&d
4、转移数据库给新用户以已存在用户权限 R=9j+74U
exec sp_change_users_login 'update_one','newname','oldname' Jl9T[QAJn1
go zJx<]=]
5、检查备份集 }7C{:H2d
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' zg5u
6、修复数据库 s!+?)bB
ALTER DATABASE [dvbbs] SET SINGLE_USER lI5{]?'
GO J#X 7Ss
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 3~ZtAgih%
GO JT:9"lmJz,
ALTER DATABASE [dvbbs] SET MULTI_USER Az)P&*2:'`
GO ;N/c 5+
7、日志清除 gVI*`$
SET NOCOUNT ON -m+2l`DLy
DECLARE @LogicalFileName sysname, aFC3yMKXh
@MaxMinutes INT, rg P$\xn-
@NewSize INT h]zx7zt-
USE tablename -- 要操作的数据库名 \Xkx`C
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 i3Ffk+ |b
@MaxMinutes = 10, -- Limit on time allowed to wrap log. l"cO@.T3
@NewSize = 1 -- 你想设定的日志文件的大小(M) i"-#1vy=
-- Setup / initialize VK NCK
DECLARE @OriginalSize int .:lzT"QXI
SELECT @OriginalSize = size D<rjxP
FROM sysfiles ]&9f:5',
WHERE name = @LogicalFileName |]I?^:I
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Ik}*7D
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !c*^:0
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' T}\U:@b
FROM sysfiles &O%Kj8)
WHERE name = @LogicalFileName ;nC+Kz:
CREATE TABLE DummyTrans J%[K;WjrZJ
(DummyColumn char (8000) not null) xpS#l"dr
DECLARE @Counter INT, c/hml4
@StartTime DATETIME, kQH!`-n:T
@TruncLog VARCHAR(255) @RnG K 5
SELECT @StartTime = GETDATE(), 3s|tS2^4
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' r7IhmdA
DBCC SHRINKFILE (@LogicalFileName, @NewSize) L~yy;)]W
EXEC (@TruncLog) gZPJZN/cpz
-- Wrap the log if necessary. o+ tY[UX
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "@f`O
AND (@OriginalSize * 8 /1024) > @NewSize h`vM+,I
BEGIN -- Outer loop. *wSl~J|ZM%
SELECT @Counter = 0 #Y{"`5>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) jf%Ydr}`
BEGIN -- update k5ZwGJ#r
INSERT DummyTrans VALUES ('Fill Log') =W4cWG?+
DELETE DummyTrans P/y-K0u
SELECT @Counter = @Counter + 1 ^X_%e |
END f9&D1Gh+w
EXEC (@TruncLog) ^Krkf4fO
END pa\]@;P1
SELECT 'Final Size of ' + db_name() + ' LOG is ' + D{8V^%{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + '@:;oe@]
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L?Lp``%bI7
FROM sysfiles MP3E]T~:
WHERE name = @LogicalFileName leD?yyjw7
DROP TABLE DummyTrans Bf-&[ 5N}
SET NOCOUNT OFF i\<l&W
8、说明:更改某个表 Y] n^(V
exec sp_changeobjectowner 'tablename','dbo' G_o/ lIz"
9、存储更改全部表 |Jq/kmn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch vAVoFL
@OldOwner as NVARCHAR(128), GN>T }
@NewOwner as NVARCHAR(128) OE[/sv
AS 1/{:}9Z@
DECLARE @Name as NVARCHAR(128) 2HTZ,W
DECLARE @Owner as NVARCHAR(128) B;-oa;m:E=
DECLARE @OwnerName as NVARCHAR(128) '<Vvv^Er
DECLARE curObject CURSOR FOR 6=kd4'yV
select 'Name' = name, |FNP~5v
'Owner' = user_name(uid) ;N
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from sysobjects hm5<_(F!
where user_name(uid)=@OldOwner &=/.$i-w$
order by name 5(F!*6i>
OPEN curObject ?(|!VLu
FETCH NEXT FROM curObject INTO @Name, @Owner z^oi15D|{
WHILE(@@FETCH_STATUS=0) .CYq+^
BEGIN {-E{.7
if @Owner=@OldOwner \(z)]D
begin 4s"HO/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) O-G@To3\
exec sp_changeobjectowner @OwnerName, @NewOwner Fj5^_2MU:
end 97BL%_^k
-- select @name,@NewOwner,@OldOwner SEuj=Vie#
FETCH NEXT FROM curObject INTO @Name, @Owner Ft|a/e
END eIEcj<f
close curObject -p)HH@6a
deallocate curObject NT-du$!u
GO pG4Hy$e
10、SQL SERVER中直接循环写入数据 u.arkp
declare @i int OC[a?#R1
set @i=1 HKh)T$IZM
while @i<30 gr7W&2x7\
begin Y#Z&$&n
insert into test (userid) values(@i) mDq01fU4
set @i=@i+1 tL3(( W"
end :*8@MjZ4
小记存储过程中经常用到的本周,本月,本年函数 xL!05du
Dateadd(wk,datediff(wk,0,getdate()),-1) HN3
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Dateadd(wk,datediff(wk,0,getdate()),6) jt]+(sx
Dateadd(mm,datediff(mm,0,getdate()),0) Te.hXCFD
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) SZ0Zi\W
Dateadd(yy,datediff(yy,0,getdate()),0) E+01"G<Q
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \
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上面的SQL代码只是一个时间段 `\qU.m0(j
Dateadd(wk,datediff(wk,0,getdate()),-1) ?ph"|LyL
Dateadd(wk,datediff(wk,0,getdate()),6) MKH7d/x
就是表示本周时间段. ' 1mygplW
下面的SQL的条件部分,就是查询时间段在本周范围内的: HL)1{[|`
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) EU\1EBT^
而在存储过程中 *$s)p >
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) eHjR/MMr_
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) :l7\7IT