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。 }*~EA=YN;
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一、基础 Hut
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1、说明:创建数据库 u:pdY'`"#
CREATE DATABASE database-name " -4V48ci
2、说明:删除数据库 j[XA"DZR<
drop database dbname /vl]Oa&U
3、说明:备份sql server :>$)Snqo=n
--- 创建 备份数据的 device z^Nnt
USE master :5G3uN+\
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ${#5$U+kI
--- 开始 备份 ^j?\_r'j
BACKUP DATABASE pubs TO testBack L!3AiAnr
4、说明:创建新表 q!k
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AF1";duA
根据已有的表创建新表: <R7*00
A:create table tab_new like tab_old (使用旧表创建新表) `)F lb|da
B:create table tab_new as select col1,col2... from tab_old definition only eB78z@
5、说明:删除新表 z
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drop table tabname UAT46
6、说明:增加一个列 %Yg;s'F>#q
Alter table tabname add column col type j=)Cyg3_%
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。 z0V d(QL
7、说明:添加主键: Alter table tabname add primary key(col) ,9q=2V[GP
说明:删除主键: Alter table tabname drop primary key(col) ;^:9huN
8、说明:创建索引:create [unique] index idxname on tabname(col....) ch<Fi%)
删除索引:drop index idxname GV1\8OG7
注:索引是不可更改的,想更改必须删除重新建。 ~ X8U@f
9、说明:创建视图:create view viewname as select statement Y;je ::"
删除视图:drop view viewname i+yqsYKO
10、说明:几个简单的基本的sql语句 a}a_&rf~Z
选择:select * from table1 where 范围 p#O#MN*
插入:insert into table1(field1,field2) values(value1,value2) =iRi9r'l
删除:delete from table1 where 范围 !Y-MUZ$f
更新:update table1 set field1=value1 where 范围 4@|K^nT`
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! -vI?b#
排序:select * from table1 order by field1,field2 [desc] .b]g#Du=
总数:select count as totalcount from table1 v@;:aN
求和:select sum(field1) as sumvalue from table1 PGMu6$
平均:select avg(field1) as avgvalue from table1 C8cB Lsa[J
最大:select max(field1) as maxvalue from table1 D5)qmu
最小:select min(field1) as minvalue from table1 6g!#"=ls;
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11、说明:几个高级查询运算词 #6_?7 (X
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A: UNION 运算符 EuqmA7s8A
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。 ~)D2U:"^xm
B: EXCEPT 运算符 C81+nR
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。 kf0zL3|
C: INTERSECT 运算符 VG+Yhm<SL
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。 B8 -/C\
注:使用运算词的几个查询结果行必须是一致的。 ;u,%an<(
12、说明:使用外连接 |hehROUn
A、left outer join: "OFYVK\]i
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 ^Tc9
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 \SnW(,`o X
B:right outer join: kR6rf_-[
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。 88h-.\%Z
C:full outer join: +Bv{A3E9
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。 knpb$eX4
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二、提升 Q<zL;AJ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) x2/|i?ZO
法一:select * into b from a where 1<>1 LLg ']9
法二:select top 0 * into b from a z7MJxjH
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) a9"x_IVU
insert into b(a, b, c) select d,e,f from b; <8!mmOK1
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) e>1^i;f
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 oScHmGFv
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. M{zzXE[@
4、说明:子查询(表名1:a 表名2:b) A) p}AEBc
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) QY-P!JD
5、说明:显示文章、提交人和最后回复时间 NaG1j+LN
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ZP*Hx
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6、说明:外连接查询(表名1:a 表名2:b) SS
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c z]Z>+|
7、说明:在线视图查询(表名1:a ) 5wRDH1z@{
select * from (SELECT a,b,c FROM a) T where t.a > 1; >9F,=63A
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 Q <^'v>~n
select * from table1 where time between time1 and time2 b.h~QyI/W
select a,b,c, from table1 where a not between 数值1 and 数值2 kX\t0'=]
9、说明:in 的使用方法 O?D*<rwD
select * from table1 where a [not] in ('值1','值2','值4','值6') ,Zzh. z::D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %fh
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *FR
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11、说明:四表联查问题: ;%]Q%7
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 ..... \Yz>=rY
12、说明:日程安排提前五分钟提醒 1]fqt[*)
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 :cG_aOkid
13、说明:一条sql 语句搞定数据库分页 _+wou(1y
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 CCp{ZH s
14、说明:前10条记录 J^pL_
select top 10 * form table1 where 范围 >AV-i$4eQ@
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) xv 's52x
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %H~q3|z
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 =nA;,9%
(select a from tableA ) except (select a from tableB) except (select a from tableC) SYB
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17、说明:随机取出10条数据 waQNX7Xdn
select top 10 * from tablename order by newid() c_O|?1
18、说明:随机选择记录 ;yY>SaQ
select newid() 3A4?9>g)KU
19、说明:删除重复记录 #; E,>0
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) o9#
20、说明:列出数据库里所有的表名 -&M9Yg|Se
select name from sysobjects where type='U' ~!,'z
21、说明:列出表里的所有的 <'-}6f3
select name from syscolumns where id=object_id('TableName') nBaY|
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 q*@7A6:FV>
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 5IBe;o
显示结果: xRP#}i:m
type vender pcs /t%IU
电脑 A 1 ??aOr*%
电脑 A 1 <QugV3e
光盘 B 2 W&}R7a@:<~
光盘 A 2 MT$OjH'Q`
手机 B 3 eq"a)QB3m
手机 C 3 X;v/$=-mz
23、说明:初始化表table1 w%VHq z$
TRUNCATE TABLE table1 K;_p>bI5
24、说明:选择从10到15的记录 _z)G!_7.>\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc JnmJN1@I
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三、技巧 +T
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1、1=1,1=2的使用,在SQL语句组合时用的较多 5X|=qZ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, I^[R]Js
如: /o.wCy,J<
if @strWhere !='' 2
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begin >wdR4!x!?
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `{N0+n
end ZJ 8~f
else W.-[ceM
begin <!Nj2>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rV"<1y:g
end ,@/b7BVv
我们可以直接写成 `U#*O+S-^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2l{g$44
2、收缩数据库 "T<Q#^m
--重建索引 | 5Mhrb4.
DBCC REINDEX uz&CUvos
DBCC INDEXDEFRAG R6h(mPYA
--收缩数据和日志 I/Hwf
DBCC SHRINKDB Ol~sCr
DBCC SHRINKFILE ?Re@`f+*
3、压缩数据库 +Ys<V
dbcc shrinkdatabase(dbname) ?c+_}ja,
4、转移数据库给新用户以已存在用户权限 /wKW
exec sp_change_users_login 'update_one','newname','oldname' Aw;~b&.U{_
go gZM\RJZ_
5、检查备份集 <o3e0JCq
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' i t,i^32|
6、修复数据库 Jq l#z/z
ALTER DATABASE [dvbbs] SET SINGLE_USER =~?2i)-mC
GO C^aP)&
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK QSW03/_f
GO 1[[`
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ALTER DATABASE [dvbbs] SET MULTI_USER u<]-%ha$
GO TCX*$ac"
7、日志清除 62PtR`b>
SET NOCOUNT ON 69!J'kM[
DECLARE @LogicalFileName sysname, eq<xO28z
@MaxMinutes INT, .D-} 2<z
@NewSize INT zM|d9TS
USE tablename -- 要操作的数据库名 iJZqAfG{m?
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ;jfjRcU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 0X~
@NewSize = 1 -- 你想设定的日志文件的大小(M) T3@wNAAU
-- Setup / initialize $`i$/FE
DECLARE @OriginalSize int b~Y$!fc
SELECT @OriginalSize = size fk5!/>X
FROM sysfiles R KFz6t
WHERE name = @LogicalFileName W7WHH \L/O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + oR[,?qu@f
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + fYuJf,I[f
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' #y&3`N z3
FROM sysfiles j_L 'Ztu3
WHERE name = @LogicalFileName k*J}/HO
CREATE TABLE DummyTrans D}SRr,4v
(DummyColumn char (8000) not null) >e/;
DECLARE @Counter INT, Cj _Q9/
@StartTime DATETIME, ZK27^oG
@TruncLog VARCHAR(255) ua0`&,a3I
SELECT @StartTime = GETDATE(), WQ\' z?P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' dFjB &#Tl
DBCC SHRINKFILE (@LogicalFileName, @NewSize) T@U_;v|rf
EXEC (@TruncLog) _.' j'j%
-- Wrap the log if necessary. HN7(-ml=B
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6m_Y%&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) pT>[w1Kk^
AND (@OriginalSize * 8 /1024) > @NewSize J|W~\(W6i
BEGIN -- Outer loop. ^cZF#%k
SELECT @Counter = 0 6Hi3h{
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) +6B(LPxgP
BEGIN -- update \tye:!a?;@
INSERT DummyTrans VALUES ('Fill Log') I?G
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DELETE DummyTrans ^'lx5+-
SELECT @Counter = @Counter + 1 e#:.JbJ:D
END UAFl+d!
EXEC (@TruncLog) vd|PTHV_
END <T)9mJYr
SELECT 'Final Size of ' + db_name() + ' LOG is ' + I+kGEHO}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + V()s!w
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L~"~C(g
FROM sysfiles azr|Fz/
WHERE name = @LogicalFileName lE78Yl]
DROP TABLE DummyTrans UA!-YTh
SET NOCOUNT OFF AY5%<CWj8
8、说明:更改某个表 .5 p"o-:D
exec sp_changeobjectowner 'tablename','dbo' MH.,dB&
9、存储更改全部表 :@y!5[88!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Y#{ L}
@OldOwner as NVARCHAR(128), T\:Vu{|
@NewOwner as NVARCHAR(128) rZLTai}`>
AS Y/2@PzA|
DECLARE @Name as NVARCHAR(128) +XLy Pj
DECLARE @Owner as NVARCHAR(128) KqG:o+V=
DECLARE @OwnerName as NVARCHAR(128) J/>Y mi,
DECLARE curObject CURSOR FOR XpJT/&4
select 'Name' = name, (@B
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'Owner' = user_name(uid) :;cKns0OA
from sysobjects G%Hr c
where user_name(uid)=@OldOwner %{!*)V\
order by name KS!mzq-
OPEN curObject !X$e;V"HX
FETCH NEXT FROM curObject INTO @Name, @Owner |>5NH'agV
WHILE(@@FETCH_STATUS=0) f>k]{W Y
BEGIN G#t!{Q}8
if @Owner=@OldOwner Rb
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begin oS 7 q#`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0j %s
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exec sp_changeobjectowner @OwnerName, @NewOwner dZFf/BXU
end qZ'&zB)
-- select @name,@NewOwner,@OldOwner EdlU}LU
FETCH NEXT FROM curObject INTO @Name, @Owner 2.{:PM4Z4
END |Gx-c
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close curObject 0k>bsn/j
deallocate curObject mY*JNx
GO _<yGen-
10、SQL SERVER中直接循环写入数据 tV%:sk^d
declare @i int $bI VD
set @i=1 }xcA`w3u2?
while @i<30 yw `w6Z3K
begin Qh<_/X?
insert into test (userid) values(@i) w6zB uW
set @i=@i+1
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end ~OD}`
小记存储过程中经常用到的本周,本月,本年函数 V|e9G,z~A
Dateadd(wk,datediff(wk,0,getdate()),-1) VI:
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Dateadd(wk,datediff(wk,0,getdate()),6) }enm#0Ha
Dateadd(mm,datediff(mm,0,getdate()),0) PN:/lIO
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) hm*1w6 =
Dateadd(yy,datediff(yy,0,getdate()),0) ghq [oK
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8fRk8
上面的SQL代码只是一个时间段 rJH u~/_Dq
Dateadd(wk,datediff(wk,0,getdate()),-1) u&z5)iU
Dateadd(wk,datediff(wk,0,getdate()),6) 3B8\r}L
就是表示本周时间段. ]&w8"q
下面的SQL的条件部分,就是查询时间段在本周范围内的: Vr@I9W;D#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) \B/+.\
而在存储过程中 lqh+yX%*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [0<N[KZ)
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) T}d%X MXq