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。 s(py7{ ^K
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一、基础 P;"moluE;
1、说明:创建数据库 \me5"ZU
CREATE DATABASE database-name -]wEk%j
2、说明:删除数据库 8XJi }YPQ
drop database dbname ECt<\h7}
3、说明:备份sql server OPN\{<`*d
--- 创建 备份数据的 device uZ8-?
USE master R'sNMWM
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1\}XL=BE
--- 开始 备份 Z,"4f*2
BACKUP DATABASE pubs TO testBack .Wt3|?\=nd
4、说明:创建新表 U
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) z&QfZs
根据已有的表创建新表: o/3.U=px~
A:create table tab_new like tab_old (使用旧表创建新表) [.4{s
B:create table tab_new as select col1,col2... from tab_old definition only e1g3a1tnWl
5、说明:删除新表 /4O))}TX
drop table tabname WowT!0$
6、说明:增加一个列 $y6 <2w%b
Alter table tabname add column col type U;/2\Ii
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 QM8Ic,QFvo
7、说明:添加主键: Alter table tabname add primary key(col) R*vQvO%)h
说明:删除主键: Alter table tabname drop primary key(col) ,c"J[$i$
8、说明:创建索引:create [unique] index idxname on tabname(col....) Vw H|ed$
删除索引:drop index idxname d<d3j9u(#
注:索引是不可更改的,想更改必须删除重新建。 CNb(\]
9、说明:创建视图:create view viewname as select statement @'>RGaPV
删除视图:drop view viewname .X%J}c$
10、说明:几个简单的基本的sql语句 EMP|I^
选择:select * from table1 where 范围 uD@ZM
插入:insert into table1(field1,field2) values(value1,value2) FD[*Q2fU
删除:delete from table1 where 范围 O*v&CHd3
更新:update table1 set field1=value1 where 范围 vyDxX
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _yg;5#3
排序:select * from table1 order by field1,field2 [desc] Lfn$Q3}O`$
总数:select count as totalcount from table1 :!MEBqcU
求和:select sum(field1) as sumvalue from table1 {U2AAQSa
平均:select avg(field1) as avgvalue from table1 HL&HY)W1gf
最大:select max(field1) as maxvalue from table1 0)SRLHTY%
最小:select min(field1) as minvalue from table1 dV[G-p
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11、说明:几个高级查询运算词 /69yR
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A: UNION 运算符 ef^GJTv&k
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。 pMT7 /y-
B: EXCEPT 运算符 ~bkO8tn
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。 k6M D3c
C: INTERSECT 运算符 el`?:dY H
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。 y>}r
注:使用运算词的几个查询结果行必须是一致的。 h&K$(}X
12、说明:使用外连接 R& t*x
A、left outer join: l6#Y}<tq
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。 _%R^8FjH*
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 +r'&6Me!
B:right outer join: kf>3T@
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。 8OZasf
C:full outer join: =q0V%h{
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。 ( 0/M?YQF
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二、提升 VOD-<
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Awa| (]
法一:select * into b from a where 1<>1 nBp6uNK[
法二:select top 0 * into b from a rwJU;wy
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) l,l qhq\
insert into b(a, b, c) select d,e,f from b; \{`^Q+<
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)
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 w^Y/J4 I0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <L8|Wz
4、说明:子查询(表名1:a 表名2:b) EtzSaB*|
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) Xgd-^
5、说明:显示文章、提交人和最后回复时间 joskKik^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b W]/J]O6
6、说明:外连接查询(表名1:a 表名2:b) ;*Vnwt A
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c qdI%v#'M
7、说明:在线视图查询(表名1:a ) _!1LV[x!s
select * from (SELECT a,b,c FROM a) T where t.a > 1; F}{%*EJ
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 QP.Lq}
select * from table1 where time between time1 and time2 -9FGFBm4]
select a,b,c, from table1 where a not between 数值1 and 数值2 ld]*J}cw
9、说明:in 的使用方法 :0:Tl/))
select * from table1 where a [not] in ('值1','值2','值4','值6') ?'0!>EjY"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 eMnK@J
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) mP\V.^
11、说明:四表联查问题: .F8[;+
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 ..... O
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12、说明:日程安排提前五分钟提醒 Lo'pNJH;$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Oe1WnS 7(]
13、说明:一条sql 语句搞定数据库分页 z(A[xN@/W<
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 1W'Ai"DLw
14、说明:前10条记录 SbGdcCB
select top 10 * form table1 where 范围 yn}Dj9(q
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.) H;4QuB'^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =tD*,2]
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 Lq5xp<
(select a from tableA ) except (select a from tableB) except (select a from tableC) `sqr>QD
17、说明:随机取出10条数据 >\[]z^J
select top 10 * from tablename order by newid() OiQf=Uz\
18、说明:随机选择记录 U.,S.WP+d
select newid() =_ pSfKR;
19、说明:删除重复记录 AwNr}9`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) zQulPU
20、说明:列出数据库里所有的表名 >fWGiFmlk
select name from sysobjects where type='U' 3!l>\#q6
21、说明:列出表里的所有的 Qwpni^D8j
select name from syscolumns where id=object_id('TableName') uQ-GJI^t
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。 =(
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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 :W, S
显示结果: PolJo?HZ
type vender pcs {EvT7W
电脑 A 1 y/\b0&
电脑 A 1 }qM^J;uy
光盘 B 2 A9b(P[!]T:
光盘 A 2 |&8XmexLb
手机 B 3 g6%]uCFB
手机 C 3 4+q,[m-$(
23、说明:初始化表table1 iY/2 `R
TRUNCATE TABLE table1 #4mRMsW5"
24、说明:选择从10到15的记录 3h:~NL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc jzV"( p!
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三、技巧 3eE=>E4,
1、1=1,1=2的使用,在SQL语句组合时用的较多 DWOf\[
"where 1=1" 是表示选择全部 "where 1=2"全部不选, eR \duZ!`
如: +"-l~`+<es
if @strWhere !='' u!|_bI3
begin ,Suk_aX>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere syBpF:`-W
end 1<'z)r4
else 7he,(V
begin ^nNY|
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]]K?Q
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end AB/${RGf+
我们可以直接写成 |K1S(m<F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Bza<.E=
2、收缩数据库 XiTi3vCe
--重建索引 nrKAK^
DBCC REINDEX |p[Mp:^^
DBCC INDEXDEFRAG &Tt7VYJfIV
--收缩数据和日志 LHA^uuBN}
DBCC SHRINKDB ij0I!ilG4
DBCC SHRINKFILE g7]S
3、压缩数据库 U!q2bF<@
dbcc shrinkdatabase(dbname) x
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4、转移数据库给新用户以已存在用户权限 @/kI;8
exec sp_change_users_login 'update_one','newname','oldname' +@?Q "B5u}
go >`UqS`YQK
5、检查备份集 dP_QkO
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ag9GYm
6、修复数据库 1ARtFR2C{b
ALTER DATABASE [dvbbs] SET SINGLE_USER }{N#JTmjB#
GO a%Q`R;W
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK c
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GO ?h4[yp=w
ALTER DATABASE [dvbbs] SET MULTI_USER "<0 !S~]
GO :bct+J}l~
7、日志清除 O80Z7
SET NOCOUNT ON T+Re1sPr?
DECLARE @LogicalFileName sysname, Oh1U=V2~
@MaxMinutes INT, ]7_>l>
@NewSize INT Hj>9 #>b
USE tablename -- 要操作的数据库名 M}o.= Iqa
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zNX=V!$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #a=]h}&1?
@NewSize = 1 -- 你想设定的日志文件的大小(M) *,G<X^
-- Setup / initialize [Ix6ArY
DECLARE @OriginalSize int ;xiN<f4B
SELECT @OriginalSize = size )8oyo~4?
FROM sysfiles .t\J@?Z
WHERE name = @LogicalFileName 9ia&/BT7"z
SELECT 'Original Size of ' + db_name() + ' LOG is ' + J.XkdGQ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + kEq~M10
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' h>!h|Ma
FROM sysfiles :epBd3f
WHERE name = @LogicalFileName A x8 >
CREATE TABLE DummyTrans YaS!YrpI
(DummyColumn char (8000) not null) Q.$8>)
DECLARE @Counter INT, R?)Yh.vi=t
@StartTime DATETIME, OE(y$+L3_I
@TruncLog VARCHAR(255) D Z*c.|W
SELECT @StartTime = GETDATE(), Vwp>:'Pu
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 9e`};DE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) zqj|$YNC
EXEC (@TruncLog) =Ya^PAj '}
-- Wrap the log if necessary. w&H>`l06
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired NE#`ZUr3
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) WVyDE1K<
AND (@OriginalSize * 8 /1024) > @NewSize uB"B{:Kz
BEGIN -- Outer loop. 1;~sNSTo
SELECT @Counter = 0 W^3 Jg2gE
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \"ogQnmz
BEGIN -- update 0"e["q{|
INSERT DummyTrans VALUES ('Fill Log') Pxf>=kY
DELETE DummyTrans >6Pe~J5,:
SELECT @Counter = @Counter + 1 EgG3XhfS
END VvIUAn
EXEC (@TruncLog) _"p(/H
END +Iuu8t
SELECT 'Final Size of ' + db_name() + ' LOG is ' + } OIe!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?cWwt~N9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' :7X4VHw/
FROM sysfiles ;L fn&2G
WHERE name = @LogicalFileName 392(N(
DROP TABLE DummyTrans SVVE b6&
SET NOCOUNT OFF ?wkT=mv
8、说明:更改某个表 ILDO/>n
exec sp_changeobjectowner 'tablename','dbo' &V
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9、存储更改全部表 A\S=>[ar-
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch p,z>:3M
@OldOwner as NVARCHAR(128), vW.f`J,\D'
@NewOwner as NVARCHAR(128) JG^GEJ
AS 4PD5i
DECLARE @Name as NVARCHAR(128) )kjQ W&)g
DECLARE @Owner as NVARCHAR(128) bJPKe]spJ=
DECLARE @OwnerName as NVARCHAR(128) fPTLPcPP
DECLARE curObject CURSOR FOR TqN@l\
select 'Name' = name, >{Ayzz>v
'Owner' = user_name(uid) 1^]IuPxq
from sysobjects N}/V2K]Q
where user_name(uid)=@OldOwner }0<2n~3P
order by name =C$"e4%Be
OPEN curObject uG'S&8i_
FETCH NEXT FROM curObject INTO @Name, @Owner h(@.bt#
WHILE(@@FETCH_STATUS=0) =),ZZD#J
BEGIN y`m0/SOT
if @Owner=@OldOwner ASEKP(]v
begin \h[*oeh
set @OwnerName = @OldOwner + '.' + rtrim(@Name) RU/WI<O
exec sp_changeobjectowner @OwnerName, @NewOwner =g6~2p=H
end W"s/8;
-- select @name,@NewOwner,@OldOwner nT:<_'!
FETCH NEXT FROM curObject INTO @Name, @Owner 5xKod0bA
END pFMJG<W9,
close curObject OD[=fR|cp
deallocate curObject |a])o
GO O=}
10、SQL SERVER中直接循环写入数据 p5rq>&"
declare @i int n'vdA !R
set @i=1 ? .B t.
while @i<30 m==DBh
begin z+oy#p6+F.
insert into test (userid) values(@i) 7~"eT9WV
set @i=@i+1 *lZ V3F
end rgXX,+cO
小记存储过程中经常用到的本周,本月,本年函数 aW_Y
Dateadd(wk,datediff(wk,0,getdate()),-1) V&j]*)
Dateadd(wk,datediff(wk,0,getdate()),6) zE8_3UC
Dateadd(mm,datediff(mm,0,getdate()),0) 3s]o~I 2x
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) tol-PJS}
Dateadd(yy,datediff(yy,0,getdate()),0) CEkf0%YJ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) p) ;[;S
上面的SQL代码只是一个时间段 eCJtNPd
Dateadd(wk,datediff(wk,0,getdate()),-1) <}&J|()
Dateadd(wk,datediff(wk,0,getdate()),6) !b0A%1W;
就是表示本周时间段. w$s6NBF7
下面的SQL的条件部分,就是查询时间段在本周范围内的: gZ>&cju
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9`qw,X&AK_
而在存储过程中 WllQM,h
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p:tp|/
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9:%')M&Q