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。 .9r+LA{
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一、基础 jSLC L'
1、说明:创建数据库 y*i_Ec\h
CREATE DATABASE database-name Ln~Z_!
2、说明:删除数据库 GTvp)^h
drop database dbname ]`[r=cG
3、说明:备份sql server RZwjc<T
--- 创建 备份数据的 device $:|z{p
USE master ldEZ _g^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :-Gf GL>]
--- 开始 备份 "'389*-
BACKUP DATABASE pubs TO testBack y^utMH
4、说明:创建新表 XQI.z7F
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) n.}A
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根据已有的表创建新表: {R`,iWV
A:create table tab_new like tab_old (使用旧表创建新表) ARcPHV<(2
B:create table tab_new as select col1,col2... from tab_old definition only A\{dq:
5、说明:删除新表 L`$m<9w'
drop table tabname 2=?/$A9p
6、说明:增加一个列 r3~~4Q4XI>
Alter table tabname add column col type tCkKJ)m
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 vn5X]U"
7、说明:添加主键: Alter table tabname add primary key(col) HTfHAc?W
说明:删除主键: Alter table tabname drop primary key(col) 0}(ZW~&1
8、说明:创建索引:create [unique] index idxname on tabname(col....) [=Qv?am
删除索引:drop index idxname ']'H8Y-M
注:索引是不可更改的,想更改必须删除重新建。 }o>6 y>=
9、说明:创建视图:create view viewname as select statement F_KPhe$
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 3Zy $NsY3
选择:select * from table1 where 范围 m53XN
插入:insert into table1(field1,field2) values(value1,value2) .uu[f2.N+
删除:delete from table1 where 范围 P F#X8+&J
更新:update table1 set field1=value1 where 范围 ,mpvGvAI
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! =P* YwLb
排序:select * from table1 order by field1,field2 [desc] \FVm_)
总数:select count as totalcount from table1 1_chO?&,I
求和:select sum(field1) as sumvalue from table1 `S&(J2KV
平均:select avg(field1) as avgvalue from table1 #g)$m}tv?
最大:select max(field1) as maxvalue from table1 HiTn 5XNf
最小:select min(field1) as minvalue from table1 z:Sr@!DZ
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11、说明:几个高级查询运算词 ^F5Q(A
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A: UNION 运算符 +4[L_
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。 a(!_3i@
B: EXCEPT 运算符 kpxWi=y
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。 *k&yD3br-V
C: INTERSECT 运算符 R-lB.9e#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。 z]P=>w
注:使用运算词的几个查询结果行必须是一致的。 aSu6SU
12、说明:使用外连接 ifo^
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A、left outer join: &C_0JyT
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。 d%IM`S;fh
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 wi{qN___
B:right outer join: yrp;G_
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。 Tt,<@U[/}
C:full outer join: P)hZFX
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。 J;?#Zt]`L
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二、提升 aT v
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) XynDo^+ru
法一:select * into b from a where 1<>1 %RlG~a
法二:select top 0 * into b from a +
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) I-@A{vvPK
insert into b(a, b, c) select d,e,f from b; Y}G 9(Ci&
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,svevo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3['aK|qk.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. y">_$
4、说明:子查询(表名1:a 表名2:b) +/">]QJ
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) %t*_Rtz\o
5、说明:显示文章、提交人和最后回复时间 L|O'X4"&_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Qktj
6、说明:外连接查询(表名1:a 表名2:b) $d<vPpJ3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ek0zFnb[Gx
7、说明:在线视图查询(表名1:a ) }|MPQy
select * from (SELECT a,b,c FROM a) T where t.a > 1; b4l=Bg"
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 iX3Y:
select * from table1 where time between time1 and time2 gBF2.{"^
select a,b,c, from table1 where a not between 数值1 and 数值2 '\vmm>
9、说明:in 的使用方法 zQ;jaS3hf
select * from table1 where a [not] in ('值1','值2','值4','值6') AKKp-I5
10、说明:两张关联表,删除主表中已经在副表中没有的信息 i{#5=np H
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ^jY'Hj.Bs
11、说明:四表联查问题: RnvPqNs
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 ..... xY3KKje
12、说明:日程安排提前五分钟提醒 pS1f y]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <!+T#)Qi
13、说明:一条sql 语句搞定数据库分页 03]
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 L4fM?{Ic:s
14、说明:前10条记录 zv1#PfO@)
select top 10 * form table1 where 范围 5PaOa8=2f
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.) `y1nex-0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) '<Nhq_u{
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 /dT7:x*
(select a from tableA ) except (select a from tableB) except (select a from tableC) !B&OK&*
17、说明:随机取出10条数据 M
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select top 10 * from tablename order by newid() h92'~X36
18、说明:随机选择记录 ;IN!H@bq
select newid() #84<aM
19、说明:删除重复记录 )#^5$5
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) v/W\k.?q/
20、说明:列出数据库里所有的表名 :h4Nfz(
select name from sysobjects where type='U' wt8?@lJ"/
21、说明:列出表里的所有的 q 9cN2|:
select name from syscolumns where id=object_id('TableName')
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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。 1@xmzTC
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 byT@O:f L
显示结果: sZ-A~X@g
type vender pcs {P/5cw
电脑 A 1 B=4xZJPy
电脑 A 1 MLu@|Xgh
光盘 B 2 |)"`v'8>
光盘 A 2 bO)voJ<
手机 B 3 /-in:gX8
手机 C 3 ?9Lp@k~TO
23、说明:初始化表table1 P^wDt14>
TRUNCATE TABLE table1 ({"jL*S,q
24、说明:选择从10到15的记录 E%A] 8y7
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc {S+ $C
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三、技巧 *wSz2o),
1、1=1,1=2的使用,在SQL语句组合时用的较多 (%bqeI!ob
"where 1=1" 是表示选择全部 "where 1=2"全部不选, z5V~m_RO
如: RDX$Wy$@L
if @strWhere !='' E%B:6
begin B+8lp4V9%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1E1oy(\V
end w1#1s|
else -&AgjzN!
begin 12D>~#J
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ys+2/>!
end u$vA9g4
我们可以直接写成 4[&L<D6h
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere IB'gY0*
2、收缩数据库 |a>W9Y m
--重建索引 g>@T5&1q*
DBCC REINDEX O]|T !
DBCC INDEXDEFRAG l\Q--
--收缩数据和日志 W8@o7svrh
DBCC SHRINKDB M%U1?^j8
DBCC SHRINKFILE .B9i`)0
3、压缩数据库 C(4r>TNm
dbcc shrinkdatabase(dbname) /t4#-vz
4、转移数据库给新用户以已存在用户权限 Wu{cE;t
exec sp_change_users_login 'update_one','newname','oldname' vs*Q {
go n7CwGN%
5、检查备份集 lhp.zl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^]{)gk8P~2
6、修复数据库 []\=(Uc;
ALTER DATABASE [dvbbs] SET SINGLE_USER ?}mbp4+j[
GO q_J)68B R
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK qHU=X"rn
GO {.,-lFb\
ALTER DATABASE [dvbbs] SET MULTI_USER 2@W'q=+0
GO 3Z taj^v
7、日志清除 )2&U
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SET NOCOUNT ON +\Zr\fOe|%
DECLARE @LogicalFileName sysname, x_X%|f
@MaxMinutes INT,
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@NewSize INT $,s"c(pv[,
USE tablename -- 要操作的数据库名 [v,Y-}wQ)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t'7A-K=k3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. l-~
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@NewSize = 1 -- 你想设定的日志文件的大小(M) #9's^}i
-- Setup / initialize eeix-Wt*E
DECLARE @OriginalSize int (8XP7c]5
SELECT @OriginalSize = size x/)o'#d$|l
FROM sysfiles @v:p)|Ne;
WHERE name = @LogicalFileName (E*pM$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^U5g7Emf
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8c1ma
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ig.9:v`
FROM sysfiles UA%tI2
WHERE name = @LogicalFileName 4:50dj
CREATE TABLE DummyTrans n/zTS3<
(DummyColumn char (8000) not null) UHaY|I${U
DECLARE @Counter INT, <,X?+hr
@StartTime DATETIME, +~ZFao qf
@TruncLog VARCHAR(255) 9pehQFfH
SELECT @StartTime = GETDATE(), IXz)xdP
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S.E'fc1
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [VL+X^
EXEC (@TruncLog) 5GHW~q!Zo\
-- Wrap the log if necessary. u A=x~-I
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired V 5
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) K+F]a]kld
AND (@OriginalSize * 8 /1024) > @NewSize P c'0.4
BEGIN -- Outer loop. :JI&ngWK
SELECT @Counter = 0 fRow@DI\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5Mb5t;4b
BEGIN -- update *~b}]M700
INSERT DummyTrans VALUES ('Fill Log') an<loLW
DELETE DummyTrans $bho]~
SELECT @Counter = @Counter + 1 "m'roU
END KhWt9=9
EXEC (@TruncLog) sf(2~BMQI
END Y}aaW[
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &4
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + .!><qVg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IT5a/;J
FROM sysfiles =D}]|ie
WHERE name = @LogicalFileName /W @k:
DROP TABLE DummyTrans o4l=oY:'
SET NOCOUNT OFF @ /yQ4Gr
8、说明:更改某个表 BQ
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exec sp_changeobjectowner 'tablename','dbo' 61*inGRB
9、存储更改全部表 PDQ\ND
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $HE ?B{
@OldOwner as NVARCHAR(128),
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@NewOwner as NVARCHAR(128) o'hwyXy/S
AS @qaK5
DECLARE @Name as NVARCHAR(128) vf&Sk`
DECLARE @Owner as NVARCHAR(128) ]y52%RAKI
DECLARE @OwnerName as NVARCHAR(128) (vXes.|+t
DECLARE curObject CURSOR FOR y(2FaTjM
select 'Name' = name, 4w)aAXK
'Owner' = user_name(uid) 4^>FN"Ve`B
from sysobjects 7c7:B2Lq
where user_name(uid)=@OldOwner !#' y#
order by name !I UH 5
OPEN curObject >AUj4d
FETCH NEXT FROM curObject INTO @Name, @Owner u@ psVt
WHILE(@@FETCH_STATUS=0) s${|A=
BEGIN Scfk]DT
if @Owner=@OldOwner $ Lf-Gi
begin rT}k[
set @OwnerName = @OldOwner + '.' + rtrim(@Name) :"utFBO
exec sp_changeobjectowner @OwnerName, @NewOwner Obl,Qa:5
end "n
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-- select @name,@NewOwner,@OldOwner B]C 9f
FETCH NEXT FROM curObject INTO @Name, @Owner YH
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END YYzl"<)c
close curObject zo{WmV7[|
deallocate curObject z}sBx9;
GO 8`4Z%;1
10、SQL SERVER中直接循环写入数据 hOTqbd}
declare @i int Y7L1`<SC
set @i=1 ex}6(;7)O
while @i<30 X61p xPa
begin fg8"fbG`:
insert into test (userid) values(@i) =w#sCy
set @i=@i+1 uz8Y)b
end /#]4lFk:h
小记存储过程中经常用到的本周,本月,本年函数 x*}*0).
Dateadd(wk,datediff(wk,0,getdate()),-1) omEnIfQSO
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) d#OE) ,`
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) Hb:@]!r>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) g,,'Pdd7Pn
上面的SQL代码只是一个时间段 $RJpn]d
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Dateadd(wk,datediff(wk,0,getdate()),-1) ? 016
Dateadd(wk,datediff(wk,0,getdate()),6) N %K%0o-
就是表示本周时间段. s<;kTReA
下面的SQL的条件部分,就是查询时间段在本周范围内的: MNzWTn@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <dA D-2O+
而在存储过程中 q/N1q&
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /A{/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6k%Lc4W