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。 6)0.q|Q
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一、基础 t O.5
1、说明:创建数据库 ~b*]jZwT
CREATE DATABASE database-name Pb;c:HeI/
2、说明:删除数据库 T5|kO:CbHq
drop database dbname a(6h`GHo
3、说明:备份sql server @*<0:Q|m
--- 创建 备份数据的 device D|Q7dIZm
USE master (_4DZMf
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' C{m%]jKH
--- 开始 备份 ?Xvy0/s5
BACKUP DATABASE pubs TO testBack vE^tdzAG
4、说明:创建新表 Cp/f18zO
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) XQn1B3k+
根据已有的表创建新表: N,K/Ya)1
A:create table tab_new like tab_old (使用旧表创建新表) wH!$TAZ:Yw
B:create table tab_new as select col1,col2... from tab_old definition only O<Q8%Az
5、说明:删除新表 &kzysv-_
drop table tabname 66F?exr
6、说明:增加一个列 z]rr
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Alter table tabname add column col type m-azd~r[
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ]w>o=<?b
7、说明:添加主键: Alter table tabname add primary key(col) ]i(/T$?~
说明:删除主键: Alter table tabname drop primary key(col) 3s?u05_
8、说明:创建索引:create [unique] index idxname on tabname(col....) tnnGM,"ol
删除索引:drop index idxname Q;VuoHj!
注:索引是不可更改的,想更改必须删除重新建。 o/7u7BQl2
9、说明:创建视图:create view viewname as select statement +'c+X^_
删除视图:drop view viewname >Y8\f:KQ
10、说明:几个简单的基本的sql语句 uarfH]T{
选择:select * from table1 where 范围 'm~=sC_uL
插入:insert into table1(field1,field2) values(value1,value2) So!=uYX
删除:delete from table1 where 范围 2`riI*fQ
更新:update table1 set field1=value1 where 范围 TMMJ5\t2
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! N8pL2y:R[P
排序:select * from table1 order by field1,field2 [desc] 2kDY+AN;
总数:select count as totalcount from table1 F4G81^H
求和:select sum(field1) as sumvalue from table1 9o5D3
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平均:select avg(field1) as avgvalue from table1 =MQ/z#:-P
最大:select max(field1) as maxvalue from table1 .\_RavW23
最小:select min(field1) as minvalue from table1 "g5{NjimY
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11、说明:几个高级查询运算词 ?110} [jw
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A: UNION 运算符 2%fIe
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。 :Q"|%#P
B: EXCEPT 运算符 2H4vK]]Nl
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。 y&
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C: INTERSECT 运算符 RVV`
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。 i:aW
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注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 #PD6LO
A、left outer join: lh'S_p8g
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。 y8s!sO
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 _xv3UzD
B:right outer join: M]r?m@)
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。 )pHlWi|h
C:full outer join: b v_UroTr
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。 ^C'0Y.H S
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二、提升 DBHy%i
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) B%;MGb o
法一:select * into b from a where 1<>1 wUCxa>h'
法二:select top 0 * into b from a }?9&xVh?\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;WSW&2
insert into b(a, b, c) select d,e,f from b; q_.fVn:!
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) W#<1504ip
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 7m-%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _aPAn|.
4、说明:子查询(表名1:a 表名2:b) =lJ
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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) "wOfs$w%s
5、说明:显示文章、提交人和最后回复时间 4`#Q
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b DSz[,AaR]
6、说明:外连接查询(表名1:a 表名2:b) 5&n{QE?Um
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c OtqFI!ns
7、说明:在线视图查询(表名1:a ) {3`385
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;_(f(8BO
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 +>q#eUS)
select * from table1 where time between time1 and time2 :_R:>n9 p
select a,b,c, from table1 where a not between 数值1 and 数值2 JaY"Wfc
9、说明:in 的使用方法 geR+v+B,
select * from table1 where a [not] in ('值1','值2','值4','值6') Y}c/wF7o
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Zigv;}#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) #; ?3kuq(
11、说明:四表联查问题: v3-'
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *vaYI3{qN
12、说明:日程安排提前五分钟提醒 Kn~Rck|
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Zl5'%b$&
13、说明:一条sql 语句搞定数据库分页 bGWfMu=n
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 hN'])[+V
14、说明:前10条记录 Tsg9,/vXM
select top 10 * form table1 where 范围 XH!#_jy
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.) KRaL+A
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) LQR2T5S/Q,
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 cFL~<
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(select a from tableA ) except (select a from tableB) except (select a from tableC) ZkbE&7Z
17、说明:随机取出10条数据 8v;^jo>ug
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 Q6Gw!!Z5EA
select newid() zi-_ l
19、说明:删除重复记录 ;>?h/tS6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Ki;SONSV~|
20、说明:列出数据库里所有的表名 -x//@8"
select name from sysobjects where type='U' 92DM1~
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21、说明:列出表里的所有的 ss)x
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select name from syscolumns where id=object_id('TableName') f4f2xe7\Q
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。 _B^zm-}8|B
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 ~18a&T:
显示结果: WBE>0L
type vender pcs C{}_Rb'x
电脑 A 1 \~5|~|9<
电脑 A 1 q7X]kr*qx
光盘 B 2 !&VfOx:PN
光盘 A 2 8?+|4:#=*J
手机 B 3 ]Btkoad
手机 C 3 *HKw;I
23、说明:初始化表table1 3 ~v
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TRUNCATE TABLE table1 B ?VTIq>
24、说明:选择从10到15的记录 7QsD"rL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc T`EV
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三、技巧 V"4Z9Qg}
1、1=1,1=2的使用,在SQL语句组合时用的较多 E8#
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, H-kX-7C
如: $`F9e5}G
if @strWhere !='' Y2
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begin Pv'Q3O2<I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,'X"(tpu@
end USBQEt
else TLdlPBnr8
begin ote,`h
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Wgwd?@uK
end j#](Q!
我们可以直接写成 _VrY7Mz:r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PXb$]HV
2、收缩数据库 iEvQ4S6tD
--重建索引 c5YPV"X
DBCC REINDEX Q7s@,c!m_
DBCC INDEXDEFRAG W7>2&$
--收缩数据和日志 +<7Oj s>o
DBCC SHRINKDB >d/H4;8
DBCC SHRINKFILE MYAt4cHc2
3、压缩数据库 OR<+y~Rv
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 '.mepxf< f
exec sp_change_users_login 'update_one','newname','oldname' k +-w%
go YT\@fgBt
5、检查备份集 g$nS6w|5H
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 5'lPXKn+L
6、修复数据库 Y?0/f[Ax,y
ALTER DATABASE [dvbbs] SET SINGLE_USER $coO~qvU
GO X ,QsE{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,;)ZF
GO JWn26,
ALTER DATABASE [dvbbs] SET MULTI_USER fvkcJwkc
GO cr1x
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7、日志清除 ?%,NOX
SET NOCOUNT ON *G19fJ[5
DECLARE @LogicalFileName sysname, =S&`~+
@MaxMinutes INT, $T'!??|IF
@NewSize INT 1+x"
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USE tablename -- 要操作的数据库名 $83B10OQ&L
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 '/W$9jm
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 8|a./%gixs
@NewSize = 1 -- 你想设定的日志文件的大小(M) )[Y B&
-- Setup / initialize mayJwBfU
DECLARE @OriginalSize int lE:g A,
SELECT @OriginalSize = size
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FROM sysfiles aB]0?C y9(
WHERE name = @LogicalFileName 4DA34m(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ~^mUu`@r
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [{x}# oRSE
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' pCIzpEsRs
FROM sysfiles %$!3Pbui
WHERE name = @LogicalFileName COrk (V
CREATE TABLE DummyTrans Rr)+M3'
(DummyColumn char (8000) not null) ht3.e[%'b
DECLARE @Counter INT, (`P\nnb
@StartTime DATETIME, lPTx] =G
@TruncLog VARCHAR(255) [0H0%z#tU&
SELECT @StartTime = GETDATE(), oo5=5s6 3}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' c`a(
DBCC SHRINKFILE (@LogicalFileName, @NewSize) d1j9{
EXEC (@TruncLog) 2QfN.<[-
-- Wrap the log if necessary. UiFH*HT
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired V`V\/s gj
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )pnyVTKt
AND (@OriginalSize * 8 /1024) > @NewSize J!I)G&:
BEGIN -- Outer loop. %Tm*^
SELECT @Counter = 0 M+/xw8}a
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'Uok<;
BEGIN -- update mB?x_6#d9
INSERT DummyTrans VALUES ('Fill Log') $NXP)Lic)
DELETE DummyTrans wKV4-uyr
SELECT @Counter = @Counter + 1 ud1M-lY\U
END .Eao|;
EXEC (@TruncLog) 3*b5V<}'|
END w:~*wv
SELECT 'Final Size of ' + db_name() + ' LOG is ' + C-'hXh;hQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + x]~TGzS
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' w0pMH p'Y
FROM sysfiles $XBK_ 5
WHERE name = @LogicalFileName zG!nqSDG
DROP TABLE DummyTrans
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SET NOCOUNT OFF _VtQMg|u
8、说明:更改某个表 {zdMmpQF
exec sp_changeobjectowner 'tablename','dbo' *H>rvE.K?
9、存储更改全部表 :=*deZ<
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^J!q>KJs
@OldOwner as NVARCHAR(128), !vnQ;g5
@NewOwner as NVARCHAR(128) ()3\(d5e
AS qUe
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DECLARE @Name as NVARCHAR(128) @f!X%)\;x
DECLARE @Owner as NVARCHAR(128) ?1e{\XW
DECLARE @OwnerName as NVARCHAR(128) QTV*m>D
DECLARE curObject CURSOR FOR #YUaM<O
select 'Name' = name, @ZKf3,J0
'Owner' = user_name(uid) W
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from sysobjects E8Dh;j
where user_name(uid)=@OldOwner yU? jmJ
order by name ; *
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OPEN curObject ~/
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FETCH NEXT FROM curObject INTO @Name, @Owner s\ IKSoE
WHILE(@@FETCH_STATUS=0) *7BfK(9T
BEGIN k;WD[SV
if @Owner=@OldOwner 4zug9kFK
begin vqf$("
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e|~MJu+1
exec sp_changeobjectowner @OwnerName, @NewOwner s='+[*&&
end pl[J!d.c
-- select @name,@NewOwner,@OldOwner @[$_cGR7
FETCH NEXT FROM curObject INTO @Name, @Owner s0kp(t!fiu
END OMGggg
close curObject 1I+9?fa
deallocate curObject gr=h!'m
GO +2tQFV;
10、SQL SERVER中直接循环写入数据 ==[,;g
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declare @i int +^)v"@,VP
set @i=1 /@os*c|je
while @i<30 +SJ.BmT
begin D$>_W ,*V
insert into test (userid) values(@i) ,pNx(a
set @i=@i+1 XQ}Zr/f6
end Fsx?(?tCMo
小记存储过程中经常用到的本周,本月,本年函数 4
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Dateadd(wk,datediff(wk,0,getdate()),-1) *O?c~UJhhV
Dateadd(wk,datediff(wk,0,getdate()),6) _n&Nw7d2
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Dateadd(mm,datediff(mm,0,getdate()),0) ngY%T5-
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n,la<N]
Dateadd(yy,datediff(yy,0,getdate()),0) &W `xZyb3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) R>Ra~b
上面的SQL代码只是一个时间段 n|`3d~9$&
Dateadd(wk,datediff(wk,0,getdate()),-1) n ]ikc|
Dateadd(wk,datediff(wk,0,getdate()),6) yPyu)
就是表示本周时间段. lame/B&nc
下面的SQL的条件部分,就是查询时间段在本周范围内的: 'U@o!\=a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (IJNBJb
而在存储过程中 _|HhT^\P
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3v* ~CQy9
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \P\Z<z7jy