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。 43@{JK9G
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一、基础 7eiV{ tYF
1、说明:创建数据库 Vb= Mg
CREATE DATABASE database-name Wh.?j>vB
2、说明:删除数据库 |b)Y#)C;
drop database dbname tfGHea)M
3、说明:备份sql server !s&NT @ S
--- 创建 备份数据的 device <UQe.K"
USE master !Y[lQXv
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' XR;eY:89
--- 开始 备份
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BACKUP DATABASE pubs TO testBack 1
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4、说明:创建新表 7BJzMlJ1Y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) BYMi6wts
根据已有的表创建新表: o<|P9#(U"
A:create table tab_new like tab_old (使用旧表创建新表) W;,C_
B:create table tab_new as select col1,col2... from tab_old definition only [_Qa9e
5、说明:删除新表 @]ytla>d
drop table tabname IWY;="
6、说明:增加一个列 =Xqc]5[i
Alter table tabname add column col type IyWI5Q"t
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。 ])nPPf
7、说明:添加主键: Alter table tabname add primary key(col) !y@6Mm
说明:删除主键: Alter table tabname drop primary key(col) CW,Wx: Y
8、说明:创建索引:create [unique] index idxname on tabname(col....) DKBSFm{~Q
删除索引:drop index idxname ::}{_ Z
注:索引是不可更改的,想更改必须删除重新建。 s;6CExH
9、说明:创建视图:create view viewname as select statement FgB&b
删除视图:drop view viewname l=v4Fa0^jF
10、说明:几个简单的基本的sql语句 ~4 `5tb
选择:select * from table1 where 范围 U15H@h
插入:insert into table1(field1,field2) values(value1,value2) j'HZ\_
删除:delete from table1 where 范围 Bq$rf < W
更新:update table1 set field1=value1 where 范围 t({W
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &FF"nE*
排序:select * from table1 order by field1,field2 [desc] [rSR:V?"a
总数:select count as totalcount from table1 \Ol kM<
求和:select sum(field1) as sumvalue from table1 _tYx~J2.Q
平均:select avg(field1) as avgvalue from table1 BS:+~| 3w
最大:select max(field1) as maxvalue from table1 yge,8i)c
最小:select min(field1) as minvalue from table1 {o.FlX
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11、说明:几个高级查询运算词 [O?z@)dx
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A: UNION 运算符 BEre*J
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 !Ikt '5/
B: EXCEPT 运算符 3ZXQoC '
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 hMykf4
C: INTERSECT 运算符 v#U"pn|M
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 /(.mp<s0
注:使用运算词的几个查询结果行必须是一致的。 sXD1C2o
12、说明:使用外连接 N-e @j4WU
A、left outer join: [<
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 a
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SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c yrC7F`.
B:right outer join: v~@pMA$(h
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。 ):b$xNn
C:full outer join: TX&Jt%
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。 x7eQ2h6O
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二、提升 IVAmV!.z
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .O0+H+
法一:select * into b from a where 1<>1 pQtJc*[!
法二:select top 0 * into b from a 'a\%L:`
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) G}ob<`o|"
insert into b(a, b, c) select d,e,f from b; H\0~#(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) O8j_0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )'6DNa[y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t+1 %RyKFB
4、说明:子查询(表名1:a 表名2:b) TjwBv6h
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) FXi{87F2
5、说明:显示文章、提交人和最后回复时间 Jc|6&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b WZ*ws[dVI
6、说明:外连接查询(表名1:a 表名2:b) VCD:3U 8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8j=}u/T@F
7、说明:在线视图查询(表名1:a ) Na?!;1]_
select * from (SELECT a,b,c FROM a) T where t.a > 1; RM!<8fXYD
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 5a hVeY
select * from table1 where time between time1 and time2 ;;:-l99
select a,b,c, from table1 where a not between 数值1 and 数值2 l@\#Ywz
9、说明:in 的使用方法 [Z}9>~m
select * from table1 where a [not] in ('值1','值2','值4','值6') $D|e>U
10、说明:两张关联表,删除主表中已经在副表中没有的信息 T<55a6NoK
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) tavpq.0O
11、说明:四表联查问题: i03w1pSH,
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 'gTb A?+@5
12、说明:日程安排提前五分钟提醒 RF%KA[Dj
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 DUC#NZgw
13、说明:一条sql 语句搞定数据库分页 \v.C]{Gzc
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 o1h={ao
14、说明:前10条记录 .U?'i<
select top 10 * form table1 where 范围 K0}pi+=
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) cM$P`{QrM
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8>WC5%f*
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 2&^]k`Aj6D
(select a from tableA ) except (select a from tableB) except (select a from tableC) @jsDq
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17、说明:随机取出10条数据 (?(zH3
select top 10 * from tablename order by newid() =Q+=
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18、说明:随机选择记录 `O[};3O&
select newid() =1 Oj*x@*4
19、说明:删除重复记录 o .qf _A
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) {:]9Q Tq
20、说明:列出数据库里所有的表名 8p@Piy{p
select name from sysobjects where type='U' [g:$K5\64
21、说明:列出表里的所有的 /M3Y~l$
select name from syscolumns where id=object_id('TableName') /qy-qUh3h
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。 pJt,9e6
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 JSTuXW
显示结果: O"c;|zCc>
type vender pcs y6[If cN
电脑 A 1 |>tKq;/
电脑 A 1 .R./0Ot tx
光盘 B 2 v,4pp@8rv
光盘 A 2 3
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手机 B 3 3P^sM1
手机 C 3 oIb|*gX^
23、说明:初始化表table1 Vc2A
TRUNCATE TABLE table1 n3D;"a3
24、说明:选择从10到15的记录 d[V;&U
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc o8-^cP1
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三、技巧 \0vr>C
1、1=1,1=2的使用,在SQL语句组合时用的较多 wT:b\km:!
"where 1=1" 是表示选择全部 "where 1=2"全部不选, t-0a7
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如: -<
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if @strWhere !='' L&%s[
begin !VI]oRgP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b7wvaRe.
end V&\[)D'c
else qIIv6''5@
begin h?8]C#6^
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' <\}KT*Xp
end
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我们可以直接写成 zN"J}r:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere P)MDPI+~
2、收缩数据库 7U2J xE
--重建索引 Ooq! 0g
DBCC REINDEX Bb}fj28
DBCC INDEXDEFRAG A3iFI9Iv
--收缩数据和日志 D(H>R&b!
DBCC SHRINKDB h?;T7|^
DBCC SHRINKFILE TG+VEL |T
3、压缩数据库 4*cU<
dbcc shrinkdatabase(dbname) #[`:'e
4、转移数据库给新用户以已存在用户权限 vWf;
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exec sp_change_users_login 'update_one','newname','oldname' li 6%)
go @qnD=mE
5、检查备份集 JAX*hGhkh
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' A?t%e
6、修复数据库 ?`#/ 8PN
ALTER DATABASE [dvbbs] SET SINGLE_USER ,}))u0q+:
GO yRfSJbzaf\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK KjE+QUa
GO Y~(Md@!0S
ALTER DATABASE [dvbbs] SET MULTI_USER <RG|Dx[:=
GO DFd%9*N
7、日志清除 HAJ 7m!P
SET NOCOUNT ON 8peDI7[|
DECLARE @LogicalFileName sysname, L>a
@MaxMinutes INT, V` 1/SQX
@NewSize INT x"{'&J[hx
USE tablename -- 要操作的数据库名 2h=!k|6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 MvWaB
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Tny%7xSx1
@NewSize = 1 -- 你想设定的日志文件的大小(M) FZtfh
-- Setup / initialize 66I"=:
DECLARE @OriginalSize int ?}a;}Q6
SELECT @OriginalSize = size
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FROM sysfiles *?Kr*]dnLl
WHERE name = @LogicalFileName ;F~LqC$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 2m35R&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + g;8jK8Kh
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' YA
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FROM sysfiles h}cy D7Wn
WHERE name = @LogicalFileName N0=ac5
CREATE TABLE DummyTrans m$W <
(DummyColumn char (8000) not null) S!3S4:]B^
DECLARE @Counter INT, - qy6Un+
@StartTime DATETIME, c(n&A~*AJ%
@TruncLog VARCHAR(255) 6^"=dn6K
SELECT @StartTime = GETDATE(), 'toa@5
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' nx^]>w
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Qe}`~a9P
EXEC (@TruncLog) Xp8]qH|K
-- Wrap the log if necessary. DJ(q
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <B6&I$Wc+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 43Qtj$F
AND (@OriginalSize * 8 /1024) > @NewSize KB'qRnkc
BEGIN -- Outer loop. sPMa]F(
SELECT @Counter = 0 ^*S)t.
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \e'R@
BEGIN -- update <p\6AnkMr
INSERT DummyTrans VALUES ('Fill Log') YJ;j x0
DELETE DummyTrans Eg2[k.{P
SELECT @Counter = @Counter + 1 MF'$~gxo
END t$xY #:
EXEC (@TruncLog) ghX|3lI\q
END krC{ed
SELECT 'Final Size of ' + db_name() + ' LOG is ' + (h5'9r
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + G_k~X"
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' W81E!RyP`
FROM sysfiles =|%Cu&
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans pm\x~3jHs
SET NOCOUNT OFF -"h;uDz|z
8、说明:更改某个表 %_{tzXim
exec sp_changeobjectowner 'tablename','dbo' hDcEGU_
9、存储更改全部表 vpld*TL*
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch sZL#xZ5
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@OldOwner as NVARCHAR(128), fD07VBS yl
@NewOwner as NVARCHAR(128) ?F6pEt4
AS _',prZ*
DECLARE @Name as NVARCHAR(128) b r^_'1
DECLARE @Owner as NVARCHAR(128) rZfN+S,g
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR _-9@qe
select 'Name' = name, ?}RSwl
'Owner' = user_name(uid) 6C]1Q.f;
from sysobjects S`"LV $8
where user_name(uid)=@OldOwner M\Z6$<H?U
order by name I-WhH>9
OPEN curObject 0em#-*|2"
FETCH NEXT FROM curObject INTO @Name, @Owner KA){''>8
WHILE(@@FETCH_STATUS=0) & M~`:R
BEGIN LF~*^n>
if @Owner=@OldOwner yfx7{naKC`
begin v}tag#f5>?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @W^| ?
exec sp_changeobjectowner @OwnerName, @NewOwner _=NwQu\_F
end }p!HT6 tZ
-- select @name,@NewOwner,@OldOwner /u0'
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FETCH NEXT FROM curObject INTO @Name, @Owner FFH_d <q
END NDs!a
close curObject mXUGe:e8
deallocate curObject q@@T]V6
GO &/uu)v
10、SQL SERVER中直接循环写入数据 &%s8L\?
declare @i int Xy@7y[s]
set @i=1 3$m4q`J
while @i<30 2Ri{bWi
begin /}PF\j9#4
insert into test (userid) values(@i) 9(5OeH6o?
set @i=@i+1 GHsilba
end qnoNT%xazo
小记存储过程中经常用到的本周,本月,本年函数 s_>
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Dateadd(wk,datediff(wk,0,getdate()),-1) CMCO}#
Dateadd(wk,datediff(wk,0,getdate()),6) |R56ho5C
Dateadd(mm,datediff(mm,0,getdate()),0) e?Ho a$k
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $zyIuJN#
Dateadd(yy,datediff(yy,0,getdate()),0) F@* +{1R
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) B7]C]=${m
上面的SQL代码只是一个时间段 }yJ$SR]t
Dateadd(wk,datediff(wk,0,getdate()),-1) -,+q#F
Dateadd(wk,datediff(wk,0,getdate()),6) ]]&M@FM2z
就是表示本周时间段. qWx][D"
下面的SQL的条件部分,就是查询时间段在本周范围内的: ~-dV^SO
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &3$z4df
而在存储过程中 *=wYuJ#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }t;(VynV)
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) V0%V5>