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。 QTtcGU
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一、基础 'd0]`2tVg4
1、说明:创建数据库 { p1#H`
CREATE DATABASE database-name |BF4F5wC?
2、说明:删除数据库 Pou`PNvH
drop database dbname DHgEhf]
3、说明:备份sql server D]Bvjh
--- 创建 备份数据的 device |u7vY/
USE master 9q;+ Al^Z
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' O .m;a_
--- 开始 备份 -~]*)&
BACKUP DATABASE pubs TO testBack 1+.(N:) +
4、说明:创建新表 2c_#q1/Z/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ()=
根据已有的表创建新表: Rco#?'
A:create table tab_new like tab_old (使用旧表创建新表) $Rd74;edn
B:create table tab_new as select col1,col2... from tab_old definition only yG2j!D
5、说明:删除新表 V!a\:%#^Y
drop table tabname Et4gRS)\
6、说明:增加一个列 aQ46euth
Alter table tabname add column col type YeptYW@xfw
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。 >N{K)a
7、说明:添加主键: Alter table tabname add primary key(col) $ R,7#7bG
说明:删除主键: Alter table tabname drop primary key(col) V)f/umT%g
8、说明:创建索引:create [unique] index idxname on tabname(col....) =|
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删除索引:drop index idxname '
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注:索引是不可更改的,想更改必须删除重新建。 *'1qA0Xc
9、说明:创建视图:create view viewname as select statement 8{(;s$H~
删除视图:drop view viewname w8%<O^wN,
10、说明:几个简单的基本的sql语句 %q`_vtUT
选择:select * from table1 where 范围 E,>/6AU
插入:insert into table1(field1,field2) values(value1,value2) Vf`1'GY
删除:delete from table1 where 范围 'Oyz/P(p
更新:update table1 set field1=value1 where 范围 9~SfZ,(
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )apqL{u:=
排序:select * from table1 order by field1,field2 [desc] Z455g/=ye
总数:select count as totalcount from table1 \|L ~#{a
求和:select sum(field1) as sumvalue from table1 &S>m+m'
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 Uw8O"}U8
最小:select min(field1) as minvalue from table1 ;*{y!pgb
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11、说明:几个高级查询运算词 1
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A: UNION 运算符 w4\b^iJz
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 WZOi,
B: EXCEPT 运算符 jeFX?]Q
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 8$xd;+`y'
C: INTERSECT 运算符 )$p<BL U
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。 w+)MrB-}
注:使用运算词的几个查询结果行必须是一致的。 $,ZBK6CT
12、说明:使用外连接 D(yU:^L
A、left outer join: %5?qS`/c(
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 0,a\vs%@X
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "CI#2tnL7
B:right outer join: a/A$
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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。 M0YV Qa
C:full outer join: LmE%`qNg
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。 zy"wQPEE
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二、提升 `CP#S7W^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A\nL(Nd
法一:select * into b from a where 1<>1 ZV=O oLt,
法二:select top 0 * into b from a 9#Gz2u $
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) R >f$*T
insert into b(a, b, c) select d,e,f from b; ?:73O`sX:
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) sOQF_X(.x
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \0?^%CD+@
4、说明:子查询(表名1:a 表名2:b) /UtCJMQ
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) Z.TYi~d/9D
5、说明:显示文章、提交人和最后回复时间 "& h;\hL
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b : $4
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6、说明:外连接查询(表名1:a 表名2:b) 8@y@}
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c N.R,[K
7、说明:在线视图查询(表名1:a ) >1u!(-A
select * from (SELECT a,b,c FROM a) T where t.a > 1; #D4gNQg@R
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 "O@L
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select * from table1 where time between time1 and time2 0wL-Ak#v
select a,b,c, from table1 where a not between 数值1 and 数值2 /E8{:>2
9、说明:in 的使用方法 $<'i+kK
select * from table1 where a [not] in ('值1','值2','值4','值6') ?XOl>IO
10、说明:两张关联表,删除主表中已经在副表中没有的信息 )%H@.;cD_r
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) c%,@O&o
11、说明:四表联查问题: r: Ij\YQ
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... [l"|x75-
12、说明:日程安排提前五分钟提醒 |Rk9W
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bn$a7\X-
13、说明:一条sql 语句搞定数据库分页 mY!os91KoO
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 Lso4ZZ;
14、说明:前10条记录 O.OPIQ=?:w
select top 10 * form table1 where 范围 /*Xr^X6
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.) "`WcE/(
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oZVq}}R
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 5MU-Eu|*>
(select a from tableA ) except (select a from tableB) except (select a from tableC) &USKudXmb
17、说明:随机取出10条数据 >|[ l?`
select top 10 * from tablename order by newid() KYe@2 6
18、说明:随机选择记录 %<[?;
select newid()
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19、说明:删除重复记录 uUy~$>V
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) W#^W1j>_G
20、说明:列出数据库里所有的表名 04npY+1
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select name from sysobjects where type='U' &:Mk^DH5
21、说明:列出表里的所有的 cviPCjM
select name from syscolumns where id=object_id('TableName') 60R Yw9d%0
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 T-.Q
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type _'OXrT#Q
显示结果:
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type vender pcs ! J7ExfEA
电脑 A 1 2^3N[pM;
电脑 A 1 MTyBGrs(
光盘 B 2 p h5rS<
光盘 A 2 %t.L;G
手机 B 3 VgBZ@*z(x
手机 C 3 S!Z2aFj
23、说明:初始化表table1 J/T$.*X
TRUNCATE TABLE table1 hv4om+
24、说明:选择从10到15的记录 L'A>IBrz
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j*7#1<T
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三、技巧 )fGIe rS
1、1=1,1=2的使用,在SQL语句组合时用的较多 ()\=(n!J
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 655OL)|cD6
如: zyh #ygH
if @strWhere !='' igGg[I1?
begin _Qh:*j!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Mtw7aK
end tjId?}\
else iL48
begin Dwx^hNh
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Kn#CIFbBN
end ^J]_O_ee$
我们可以直接写成 G*y!
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere x 8_nLZ
2、收缩数据库 3_ P<0%
--重建索引 l.iT+T
DBCC REINDEX S
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DBCC INDEXDEFRAG 8aMmz!S
--收缩数据和日志 yV4rS6=
DBCC SHRINKDB wRj||yay#-
DBCC SHRINKFILE W{l{O1,
3、压缩数据库 +qiI;C_P\
dbcc shrinkdatabase(dbname) X{BS]
4、转移数据库给新用户以已存在用户权限 tbm/gOBw
exec sp_change_users_login 'update_one','newname','oldname' QNcbl8@
go {k15!(:i~a
5、检查备份集
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' VLP'3 qX
6、修复数据库 hf1h*x^J
ALTER DATABASE [dvbbs] SET SINGLE_USER }b/Xui9Q
GO b+tm[@|,v
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK K2@],E?e%|
GO a)qlrtCl
ALTER DATABASE [dvbbs] SET MULTI_USER &VdKL2
GO h~r&7G@[}
7、日志清除 jFH wu*
SET NOCOUNT ON <KEVA?0>
DECLARE @LogicalFileName sysname, 9H%dK^C
@MaxMinutes INT, JF6=0
@NewSize INT PZYVLUw
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USE tablename -- 要操作的数据库名 dml,|k=
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. zS/1v+
@NewSize = 1 -- 你想设定的日志文件的大小(M) QZ2a1f'G
-- Setup / initialize M'sq{K9
DECLARE @OriginalSize int M=t;t0
SELECT @OriginalSize = size K4vOy_wT
FROM sysfiles iw =~j
WHERE name = @LogicalFileName E(miQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8k9q@FSln
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \]Y=*+{
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rk7d7`V
FROM sysfiles "Gc\"'^r
WHERE name = @LogicalFileName ]wHXrB8vx
CREATE TABLE DummyTrans F [S'l
(DummyColumn char (8000) not null) rGgP9
(
DECLARE @Counter INT, X ApSKJ
@StartTime DATETIME, ]r@CmwC
@TruncLog VARCHAR(255) E!
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SELECT @StartTime = GETDATE(), ~@%#eg
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,wB)hp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) |TQa=
EXEC (@TruncLog) Y5R|)x
-- Wrap the log if necessary. f=kt0
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 01">$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ;9)A+bD]
AND (@OriginalSize * 8 /1024) > @NewSize }:1*@7eR
BEGIN -- Outer loop. ;uyQ R8
SELECT @Counter = 0 7$A=|/'nSA
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) @ev8"JZ1
BEGIN -- update CQh6;[\:
INSERT DummyTrans VALUES ('Fill Log') m.&"D>
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DELETE DummyTrans kPezR:
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SELECT @Counter = @Counter + 1 r[4dGt
END w|(
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EXEC (@TruncLog) -}KW"#9c
END M2piJ'T4u
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~4=XYYcka
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 0ra+MQBg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k56*eEc
FROM sysfiles 6T-iBJT
WHERE name = @LogicalFileName 2UrE>_
DROP TABLE DummyTrans >e^8fpgSo
SET NOCOUNT OFF my*E7[
8、说明:更改某个表 ^^kL.C Ym
exec sp_changeobjectowner 'tablename','dbo' M6:$ 0(r
9、存储更改全部表 ku^0bq}BrH
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch o>MB8[r
@OldOwner as NVARCHAR(128), vg-'MG
@NewOwner as NVARCHAR(128) A}MF>.!}C
AS gjc[\"0a5h
DECLARE @Name as NVARCHAR(128) an,JV0
DECLARE @Owner as NVARCHAR(128) R0bWI`$Z
DECLARE @OwnerName as NVARCHAR(128) 91:TE8?Z
DECLARE curObject CURSOR FOR nAk;a|Q
select 'Name' = name, 4{#0ci{
'Owner' = user_name(uid) YnW,6U['{g
from sysobjects .y2np
where user_name(uid)=@OldOwner &U{"dJ r
order by name MURHv3
OPEN curObject .7r$jmuFs
FETCH NEXT FROM curObject INTO @Name, @Owner <c]?
WHILE(@@FETCH_STATUS=0) "= >8UR
BEGIN Na{&aqdz
if @Owner=@OldOwner 3TF'[(K=
begin &C.m*^`^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) H;Cv]-
exec sp_changeobjectowner @OwnerName, @NewOwner 0JX/@LNg0
end J%lEyU
-- select @name,@NewOwner,@OldOwner d1hXzJs
FETCH NEXT FROM curObject INTO @Name, @Owner "<1-9CMl
END }(v <f*7=n
close curObject U?(+ {4l
deallocate curObject XDAwE
GO c%x.cbu>
10、SQL SERVER中直接循环写入数据
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declare @i int %\?Gzc_
set @i=1 2hFj+Ay
while @i<30 cDqj&:$e
begin sT+\
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insert into test (userid) values(@i) Aj "SSX!L
set @i=@i+1 ZA8FX
end +8|r_z\A5a
小记存储过程中经常用到的本周,本月,本年函数 O`FuXB(t
Dateadd(wk,datediff(wk,0,getdate()),-1) XYHVw)
Dateadd(wk,datediff(wk,0,getdate()),6) uW^ W/S%'
Dateadd(mm,datediff(mm,0,getdate()),0) }I
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +<W8kb
Dateadd(yy,datediff(yy,0,getdate()),0) O:Ob{k
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2~q(?wY
上面的SQL代码只是一个时间段 DY!mq91
Dateadd(wk,datediff(wk,0,getdate()),-1) 8`;3`lZ
Dateadd(wk,datediff(wk,0,getdate()),6) ?%RR+(2m
就是表示本周时间段. l$eKV(CZ4
下面的SQL的条件部分,就是查询时间段在本周范围内的: Y~uqKb;A
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) C;.+ kE
而在存储过程中 ~ZXAW~a}
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Q5pm^X._j
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) IX
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