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。 7Pu.<b}
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一、基础 DDh$n?2fd
1、说明:创建数据库 QEIu}e6b
CREATE DATABASE database-name ;C,D1_20Z
2、说明:删除数据库 {Muw4DV
drop database dbname ng$`<~=)\
3、说明:备份sql server SB
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--- 创建 备份数据的 device -}nTwx:|5u
USE master A<esMDX
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]i\C4*
--- 开始 备份 bgs2~50
BACKUP DATABASE pubs TO testBack ,zmGKn#n2
4、说明:创建新表 z7X[$T$V
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _:4n&1{.E
根据已有的表创建新表: _&s37A&\
A:create table tab_new like tab_old (使用旧表创建新表) O4xV "\
B:create table tab_new as select col1,col2... from tab_old definition only 3#7D
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5、说明:删除新表 vCE1R]^A.]
drop table tabname ~D1.opj3
6、说明:增加一个列 A%S6&!I:(
Alter table tabname add column col type _U<sz{6
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。 NsYeg&>`
7、说明:添加主键: Alter table tabname add primary key(col) YGb&mD
说明:删除主键: Alter table tabname drop primary key(col) H2oAek(
8、说明:创建索引:create [unique] index idxname on tabname(col....) |pB[g>~V
删除索引:drop index idxname NWCJ|
注:索引是不可更改的,想更改必须删除重新建。 Wt2+D{@8
9、说明:创建视图:create view viewname as select statement ]DcQ8D
删除视图:drop view viewname ao>`[-
10、说明:几个简单的基本的sql语句 GrWzgO
选择:select * from table1 where 范围 (~t/8!7N
插入:insert into table1(field1,field2) values(value1,value2) ^|KX)g
删除:delete from table1 where 范围 Y'6GY*dL
更新:update table1 set field1=value1 where 范围 /8 /2#`3R
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \yeo-uN8
排序:select * from table1 order by field1,field2 [desc] 1RC(T{\x
总数:select count as totalcount from table1 u'"VbW3u n
求和:select sum(field1) as sumvalue from table1 >W%tEc
平均:select avg(field1) as avgvalue from table1 lqPzDdC^>
最大:select max(field1) as maxvalue from table1 gKK*`
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最小:select min(field1) as minvalue from table1 )sg@HFhY'
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11、说明:几个高级查询运算词 {L 7O{:J
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A: UNION 运算符 9(`d
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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。 6\4~&+;wL
B: EXCEPT 运算符 z)$X/v
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 z&!n'N<C
C: INTERSECT 运算符 ^Y"c1f2
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 6{/HNEI*1
注:使用运算词的几个查询结果行必须是一致的。 a!ao{8#
12、说明:使用外连接 -A}U^-'a}
A、left outer join: 5AV5`<r.
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 P~Cx#`#(V
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <C0~7]XO
B:right outer join: %<cfjo
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 *^]Hqf(`
C:full outer join: 0zR4Kj7EE
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 EN^C'n
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二、提升 Vo*38c2
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^^MVd@,i
法一:select * into b from a where 1<>1 g~EJja;
法二:select top 0 * into b from a FSnF>3kj-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) WZkAlg7Z
insert into b(a, b, c) select d,e,f from b; 0'ha!4h3Z
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 9/N=7<$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 "p<B|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. u*#j;Xc
4、说明:子查询(表名1:a 表名2:b) s>8;At-
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) =?Y%w%2
5、说明:显示文章、提交人和最后回复时间 CT1)tRN
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b fhCMbq4T
6、说明:外连接查询(表名1:a 表名2:b)
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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 ^,`;x
7、说明:在线视图查询(表名1:a ) tz{W69k+
select * from (SELECT a,b,c FROM a) T where t.a > 1; Lyjt$i W%
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 /(#;(]
select * from table1 where time between time1 and time2 0"q ^`@sZ
select a,b,c, from table1 where a not between 数值1 and 数值2 $ekJs/I&
9、说明:in 的使用方法 qi!Nv$e
select * from table1 where a [not] in ('值1','值2','值4','值6') [o]^\ay
10、说明:两张关联表,删除主表中已经在副表中没有的信息 *m_B#~4
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) o /uA_19
11、说明:四表联查问题: zqqu7.`
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 ..... vMBF7Jfx
12、说明:日程安排提前五分钟提醒 ?2D1gjr
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 D@:w/W
13、说明:一条sql 语句搞定数据库分页 C(( 7
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 sB|>\O#-
14、说明:前10条记录 )%e`SGmp
select top 10 * form table1 where 范围 _=ani9E]uF
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.) >^vyp!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7v9l+OX,6
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 QH:PClW![
(select a from tableA ) except (select a from tableB) except (select a from tableC) #3!l6]
17、说明:随机取出10条数据 q'u^v PO
select top 10 * from tablename order by newid() o&tETJ5Bhe
18、说明:随机选择记录 :CH?,x^!@
select newid() !?t#QDo
19、说明:删除重复记录 dW
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) >l|ao&z>bm
20、说明:列出数据库里所有的表名 zd1X(e<|{
select name from sysobjects where type='U' H^UuT
21、说明:列出表里的所有的 bB01aiUw@l
select name from syscolumns where id=object_id('TableName') k@HV
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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。 O5^!\j.WR
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 y#%*aV}|B
显示结果: ?f{{{0$S
type vender pcs u,]?_bK)
电脑 A 1 &DnX6%2
电脑 A 1 RLuA^ONI
光盘 B 2 X%iiz
光盘 A 2 Oj6PmUK4
手机 B 3 n)]]g3y2
手机 C 3 <PCa37
23、说明:初始化表table1 #SNwSx&
TRUNCATE TABLE table1 Ja$Ple*XU8
24、说明:选择从10到15的记录 k%UE^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]xhZJ~"@u
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三、技巧 3LT[?C]H$
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, ,{{e'S9cy
如: :u}FF"j
if @strWhere !='' \F_~?$
begin -oSfp23u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mJjd2a"vi
end &p/^A[
else =uM2l
begin lFHj]%Y
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' {rp5qgVE<
end :el]IH
我们可以直接写成 xiv1y4(%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2<18j
2、收缩数据库 [ArPoJt
--重建索引 GR@jn]50
DBCC REINDEX Yv="oG!xL
DBCC INDEXDEFRAG d9'gH#f?
--收缩数据和日志 &YAw~1A
DBCC SHRINKDB kB41{Y -
DBCC SHRINKFILE Yo`#G-]
3、压缩数据库 >Q159qZ
dbcc shrinkdatabase(dbname) ~N2<-~=si
4、转移数据库给新用户以已存在用户权限 _0Mt*]L }
exec sp_change_users_login 'update_one','newname','oldname' p-p]dV
go $9_yD&&
5、检查备份集 zqd_^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' HvhP9_MB
6、修复数据库 <+0TN]?
ALTER DATABASE [dvbbs] SET SINGLE_USER ~Q q0
GO *{}Y
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1trk
GO 4g^nhJP$
ALTER DATABASE [dvbbs] SET MULTI_USER $@H]0<3,
GO Qw&It
7、日志清除 MiB"CcU
SET NOCOUNT ON u$A*Vsmr
DECLARE @LogicalFileName sysname, |&O7F;/_
@MaxMinutes INT, z:
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@NewSize INT *|Cmm>z"7
USE tablename -- 要操作的数据库名 :?LUv:G
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ne6]?\Z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. @@&([f
@NewSize = 1 -- 你想设定的日志文件的大小(M) n\l$R!zr
-- Setup / initialize C7|zDJ_
DECLARE @OriginalSize int zkFx2(Hq-f
SELECT @OriginalSize = size 2m$\]\kCUv
FROM sysfiles RgF5w<Vd.
WHERE name = @LogicalFileName Rh%c<</`0s
SELECT 'Original Size of ' + db_name() + ' LOG is ' + $Tc"7nYu
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + W{z7h[?5,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' A^ :/*
FROM sysfiles 5e> <i
WHERE name = @LogicalFileName _z`g@[m:t
CREATE TABLE DummyTrans ,U-aZ
(DummyColumn char (8000) not null) ;cye
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DECLARE @Counter INT, -UJ; =/
@StartTime DATETIME, pA
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@TruncLog VARCHAR(255) VR/*h%
SELECT @StartTime = GETDATE(), >^<%9{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &W'X3!Te
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7hg)R
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EXEC (@TruncLog) ;@I4[4ph}
-- Wrap the log if necessary. 1:L _qL
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired t%xD epFQ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) h5vvizruy
AND (@OriginalSize * 8 /1024) > @NewSize jJ(()EJ
BEGIN -- Outer loop. 'a}<|Et.
SELECT @Counter = 0 82mKI+9&"
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) U{^~X_?
BEGIN -- update Iuh1tcc
INSERT DummyTrans VALUES ('Fill Log') _trF /U<
DELETE DummyTrans 9Z KB,
SELECT @Counter = @Counter + 1 yXuc<m
END KF'DOXBw>
EXEC (@TruncLog) 3,x|w
END n"p|tEK
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Stw%OP@?
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + a{oG[e
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 38I .1p9
FROM sysfiles @U~i<kt
WHERE name = @LogicalFileName h3}gg@Fm
DROP TABLE DummyTrans sBsf{%I[{
SET NOCOUNT OFF Q Pel n)
8、说明:更改某个表 9GH11B_A
exec sp_changeobjectowner 'tablename','dbo' u{Z
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9、存储更改全部表
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Kbdjd p
@OldOwner as NVARCHAR(128), ?9F_E+!
@NewOwner as NVARCHAR(128) HAkEJgV
AS nE4?oq
DECLARE @Name as NVARCHAR(128) V l,V
DECLARE @Owner as NVARCHAR(128) 7q%<JZPY
DECLARE @OwnerName as NVARCHAR(128) !uoQLiH+
DECLARE curObject CURSOR FOR V3^=Mj2"
select 'Name' = name, R]s\s[B
'Owner' = user_name(uid) E{Gkq:
from sysobjects #
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where user_name(uid)=@OldOwner qUZm6)p6[a
order by name v,=[!=8!
OPEN curObject UUE:>[,
FETCH NEXT FROM curObject INTO @Name, @Owner c^4^z"Mo`
WHILE(@@FETCH_STATUS=0) ,wyfMOGLt
BEGIN R F)Qsa
if @Owner=@OldOwner WcG!6.U>
begin F|rJ{=x
set @OwnerName = @OldOwner + '.' + rtrim(@Name) IvW%n(a8^
exec sp_changeobjectowner @OwnerName, @NewOwner s8/sH];
end gM0^k6bB8
-- select @name,@NewOwner,@OldOwner aJQx"6c?
FETCH NEXT FROM curObject INTO @Name, @Owner Z#J
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END ~+JEl%
close curObject Sqc
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deallocate curObject ?Aewp$Bj
GO Ezvm5~<
10、SQL SERVER中直接循环写入数据 xaM?
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declare @i int nBVR)|+M
set @i=1 l'~~hQ{h/
while @i<30 U}6FB =
begin E[z8;A^:0
insert into test (userid) values(@i) B4/0t:^I
set @i=@i+1 ?iX1;c9
end efK3{
小记存储过程中经常用到的本周,本月,本年函数 C(ay7
Dateadd(wk,datediff(wk,0,getdate()),-1) Lq-Di|6q
Dateadd(wk,datediff(wk,0,getdate()),6) T)!$-qdz/
Dateadd(mm,datediff(mm,0,getdate()),0) $?Et sf#*'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) YY&3M
Dateadd(yy,datediff(yy,0,getdate()),0) R(i2TAaaU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) )ZyEn%
上面的SQL代码只是一个时间段 I3{koI
Dateadd(wk,datediff(wk,0,getdate()),-1) 1l8kuwH
Dateadd(wk,datediff(wk,0,getdate()),6) u-31$z<<5}
就是表示本周时间段. e:h(,
下面的SQL的条件部分,就是查询时间段在本周范围内的: POnI&y]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) jJX-S
而在存储过程中 (c'=jJX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) h1y6`m9
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y .+d3