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。 JXIxk"m
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一、基础 ~S, R`wo
1、说明:创建数据库 xQ=sZv^M
CREATE DATABASE database-name |99/?T-QW
2、说明:删除数据库 eZMDt B
drop database dbname jLRh/pbz4
3、说明:备份sql server 8(Ab
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--- 创建 备份数据的 device ShV#XnQ
USE master F5|6* K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R"9^FQ13
--- 开始 备份 "Vg1'd}f
BACKUP DATABASE pubs TO testBack 3S~Gi,
4、说明:创建新表 .MzVc42<
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hv.$p5UY*
根据已有的表创建新表: \Y0o~JD
A:create table tab_new like tab_old (使用旧表创建新表) [%alnY
B:create table tab_new as select col1,col2... from tab_old definition only AUm"^-@x#>
5、说明:删除新表 c05kHB$O
drop table tabname oK5"RW
6、说明:增加一个列 ([r4N#lx
Alter table tabname add column col type oWu2}#~z_
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。 T5g}z5~"
7、说明:添加主键: Alter table tabname add primary key(col) x9s7:F
说明:删除主键: Alter table tabname drop primary key(col) k e
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8、说明:创建索引:create [unique] index idxname on tabname(col....) :QGd/JX$n`
删除索引:drop index idxname 2|KgRk|!
注:索引是不可更改的,想更改必须删除重新建。 N<|_tC+ct
9、说明:创建视图:create view viewname as select statement G98P<cyD
删除视图:drop view viewname wsnR$FhQ`
10、说明:几个简单的基本的sql语句 aeQvIob@
选择:select * from table1 where 范围 [zO:[i 7
插入:insert into table1(field1,field2) values(value1,value2) 9Q<8DMX^
删除:delete from table1 where 范围 Nm.H
更新:update table1 set field1=value1 where 范围 K\7\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! [<+A?M=
排序:select * from table1 order by field1,field2 [desc] QU]&q`GE
总数:select count as totalcount from table1 fZqqU|tq
求和:select sum(field1) as sumvalue from table1 &p)]Cl/`
平均:select avg(field1) as avgvalue from table1 xpWx6
最大:select max(field1) as maxvalue from table1 X2?
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最小:select min(field1) as minvalue from table1 SM;*vkwz~
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11、说明:几个高级查询运算词 lTe7n'y^^
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A: UNION 运算符 L9| 55z
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。 ^usZ&9"@P
B: EXCEPT 运算符 J4yL"iMt
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。 Ry@QJn I<
C: INTERSECT 运算符 6`>WO_<z
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。 o7/S'Haxc]
注:使用运算词的几个查询结果行必须是一致的。 E<j}"W$a
12、说明:使用外连接 p(jY2&g
A、left outer join: pSjJ u D
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。 0]3 ,0s $}
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c hV(>}hb
B:right outer join: WF)(Q~op0U
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 G E=J Y
C:full outer join: I~'%
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 l EcZ/
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二、提升 #H'j;=]:
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) _2eRH@T
法一:select * into b from a where 1<>1 O_zW/#
法二:select top 0 * into b from a LW={| 3}
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) P=.yXirm?
insert into b(a, b, c) select d,e,f from b; mv5=>Xc6
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) +VJS/
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ! :[`>=!
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. #Tz$ona
4、说明:子查询(表名1:a 表名2:b) a.n;ika]-
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) BGtr= &Hq
5、说明:显示文章、提交人和最后回复时间 B6N/nCvHK
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b n{d0}N=
6、说明:外连接查询(表名1:a 表名2:b) #41xzN
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^#|Sl D]
7、说明:在线视图查询(表名1:a ) $pKlF0 .
select * from (SELECT a,b,c FROM a) T where t.a > 1; KASuSg+
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 n~1F[ *
select * from table1 where time between time1 and time2 RcZg/{[{
select a,b,c, from table1 where a not between 数值1 and 数值2 4LEWOWF}
9、说明:in 的使用方法 ($Cy-p
select * from table1 where a [not] in ('值1','值2','值4','值6') ~4 ~c+^PF
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9H~2
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) GI+x,p
11、说明:四表联查问题: }McqoZ%F
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 ..... 8#m,TOp
12、说明:日程安排提前五分钟提醒 @q98ac*{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <r9L-4
13、说明:一条sql 语句搞定数据库分页 S:bYeD4
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 FAkrM?0/
14、说明:前10条记录 {\1:2UKkr
select top 10 * form table1 where 范围 C+0MzfLgf
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.) 4YV0v,z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) CPW^pGT+i
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 3WVH8S b
(select a from tableA ) except (select a from tableB) except (select a from tableC) yt'P,m
17、说明:随机取出10条数据 Q #Tg)5.\
select top 10 * from tablename order by newid() e(=() :4is
18、说明:随机选择记录 ^n?`l ^9c$
select newid() Udi
19、说明:删除重复记录 -JEiwi ,
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) w)rd--9f
20、说明:列出数据库里所有的表名 |p .o ^
select name from sysobjects where type='U' tx*L8'jlN
21、说明:列出表里的所有的 4'+g/i1S
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select name from syscolumns where id=object_id('TableName') 3 T1,:r
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。 9\zasa
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 (#c|San
显示结果: 1dhuLN%Ce
type vender pcs *8bj3A]vf
电脑 A 1 2zV{I*
电脑 A 1 `j1b5&N;7
光盘 B 2 W ZT) LYA
光盘 A 2 f7SMO-3a
手机 B 3 }Q?a6(4
手机 C 3 8.!+Hm4
23、说明:初始化表table1 n)Z u>
TRUNCATE TABLE table1 )n&6= Li
24、说明:选择从10到15的记录 Op'&c0l
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc T4nWK!}z
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三、技巧 hh-a+]
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1、1=1,1=2的使用,在SQL语句组合时用的较多 f<{f/lU@
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n *EGOS
如: -N'wKT5
if @strWhere !='' 3#0y.. F
begin 3xz|d`A
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -q]5@s/
end HU/2P` DGP
else <])]1r8
begin | .gE9'"bv
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' S,s#D9NU
end I
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我们可以直接写成 &P,uK+C4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }1DzWS-hh
2、收缩数据库 ~dC.,"
--重建索引 Uc,J+j0F
DBCC REINDEX y`i?Qo3
DBCC INDEXDEFRAG ckb(+*+l
--收缩数据和日志 1%C EUE
DBCC SHRINKDB :-WNw
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DBCC SHRINKFILE }[=)sb_
3、压缩数据库 %^d<go^
dbcc shrinkdatabase(dbname)
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4、转移数据库给新用户以已存在用户权限 2rW9ja
exec sp_change_users_login 'update_one','newname','oldname' O+|ipw*B%
go C23p1%#1
5、检查备份集 ff7#LeB9
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @u`W(Ow
6、修复数据库 ~;z]
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ALTER DATABASE [dvbbs] SET SINGLE_USER _^eiN'B
GO -\USDi(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w?zy/+N~
GO p>i8aN
ALTER DATABASE [dvbbs] SET MULTI_USER $)nPj_h
GO +V(^"Z~
7、日志清除 vS"h`pL
SET NOCOUNT ON X- X`Z`o
DECLARE @LogicalFileName sysname, 3AglvGK7{
@MaxMinutes INT, 2
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@NewSize INT Hj(K*z
USE tablename -- 要操作的数据库名 c|(J%@B)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Caz5q|Oo
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?A3u2-
@NewSize = 1 -- 你想设定的日志文件的大小(M) IN@o9pUjV
-- Setup / initialize Sa%%3_&
DECLARE @OriginalSize int # S/n3
SELECT @OriginalSize = size _!VtM#G[
FROM sysfiles :iLRCK3C
WHERE name = @LogicalFileName *];QPi~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,(Ol]W}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + UmvnVmnv
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' B=;kC#Emtf
FROM sysfiles }!{R;,5/n
WHERE name = @LogicalFileName ke!
CREATE TABLE DummyTrans )/vom6y*
(DummyColumn char (8000) not null) @C!&lrf3
DECLARE @Counter INT, #rF`Hk:
@StartTime DATETIME, 4`)r1D!U
@TruncLog VARCHAR(255) f^*Yqa
SELECT @StartTime = GETDATE(), [|YvVA
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' `"[qb ?z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) vb?.`B_>&
EXEC (@TruncLog) ~c<8;,cjYR
-- Wrap the log if necessary. N&p0Emg
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {d*OJ/4
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) W6}>iB
AND (@OriginalSize * 8 /1024) > @NewSize 7l$
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BEGIN -- Outer loop. >qOG^{&x
SELECT @Counter = 0 AEaN7[PQx|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) qPD(D{,f$
BEGIN -- update m7y[Y
INSERT DummyTrans VALUES ('Fill Log') W90!*1
DELETE DummyTrans YC8IwyL'
SELECT @Counter = @Counter + 1 1P[x.t#
END CEI"p2
EXEC (@TruncLog) =k.%#h{
END _J!&R:]$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !L9OJ1F
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + NJ.oM E@=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [.fh2XrVM
FROM sysfiles xl`AiO `K
WHERE name = @LogicalFileName /q\e&&e
DROP TABLE DummyTrans OqIXFX"
SET NOCOUNT OFF G\BZ^SwE
8、说明:更改某个表 n<j+KD#a
exec sp_changeobjectowner 'tablename','dbo' {eI'0==
9、存储更改全部表 0y,w\'j
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch yD7}
@OldOwner as NVARCHAR(128), PIa!NPy
@NewOwner as NVARCHAR(128) |&JeJ0k>~
AS :=;{w~D
DECLARE @Name as NVARCHAR(128) $'3xl2T
DECLARE @Owner as NVARCHAR(128) U< G 2tn(
DECLARE @OwnerName as NVARCHAR(128) c?HUW
DECLARE curObject CURSOR FOR 7$lnCvm
select 'Name' = name, 9/{ zS3h3
'Owner' = user_name(uid) .>F4s_6l
from sysobjects KH;~VR8"/
where user_name(uid)=@OldOwner ]<f(@]R/d
order by name <A)M^,#o
OPEN curObject YPI)^ }
FETCH NEXT FROM curObject INTO @Name, @Owner A_oZSUrR
WHILE(@@FETCH_STATUS=0) jW`JThoq
BEGIN 4($"4>BA
if @Owner=@OldOwner n_km]~
begin ? /z[Jx.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) vHpw?(]
exec sp_changeobjectowner @OwnerName, @NewOwner xt5/`C
end `T[@ -
-- select @name,@NewOwner,@OldOwner R\3a Sx L
FETCH NEXT FROM curObject INTO @Name, @Owner D;V[9E=g/
END NUltuM
close curObject dJ6fPB|k
deallocate curObject 0,t%us/q
GO X>o9mW
10、SQL SERVER中直接循环写入数据
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declare @i int X n!mdR
set @i=1 WsV"`ij#
while @i<30 (~^fx\-S
begin 2uE<mjCt-r
insert into test (userid) values(@i) f(m,!
set @i=@i+1 43AzNXWF8
end "g"a-{8
小记存储过程中经常用到的本周,本月,本年函数 ,sAAV%">
Dateadd(wk,datediff(wk,0,getdate()),-1) @Uez2?
Dateadd(wk,datediff(wk,0,getdate()),6) TsaQR2J@
Dateadd(mm,datediff(mm,0,getdate()),0) Z*co\ pW
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 11yXI[
Dateadd(yy,datediff(yy,0,getdate()),0) zg<-%r'$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) w7U]-MW6A*
上面的SQL代码只是一个时间段
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Dateadd(wk,datediff(wk,0,getdate()),-1) 2P"9m
Dateadd(wk,datediff(wk,0,getdate()),6) $gBQ5Wd
就是表示本周时间段. M-"j8:en
下面的SQL的条件部分,就是查询时间段在本周范围内的: mgjJNzclL
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ux&"TkEp
而在存储过程中 \tI%[g1M
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) yv[j
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) yQ[;y~W