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。 1i#M(u_
|HhUU1!
wM_k D
一、基础 l#V"14y
1、说明:创建数据库 ~48Uch\LG:
CREATE DATABASE database-name |f?tyQ
2、说明:删除数据库 9m%[
y1v0
drop database dbname 5Y_)%u
3、说明:备份sql server [bH6>{3u
--- 创建 备份数据的 device K7U`
USE master ![{> f6{J
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' W@JmG`Sy
--- 开始 备份 :a[L-lr`e
BACKUP DATABASE pubs TO testBack :W-"UW,
4、说明:创建新表 g}P.ksM
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;r"YZs&Xd
根据已有的表创建新表: ^szCf|SM
A:create table tab_new like tab_old (使用旧表创建新表) P*)}ENY
B:create table tab_new as select col1,col2... from tab_old definition only $IUT5Gia`
5、说明:删除新表 *";,HG?|Iz
drop table tabname Ef:.)!;jy
6、说明:增加一个列 Mw*R~OX
Alter table tabname add column col type rRly0H
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 +8v^J8q0
7、说明:添加主键: Alter table tabname add primary key(col) ^e8~eL+
说明:删除主键: Alter table tabname drop primary key(col) `SZ^~O
8、说明:创建索引:create [unique] index idxname on tabname(col....) : H0+} =
删除索引:drop index idxname 3?.3Z!H/
注:索引是不可更改的,想更改必须删除重新建。 '
DCrSa>
9、说明:创建视图:create view viewname as select statement Qpe&_.&RE
删除视图:drop view viewname t'
o:aI
10、说明:几个简单的基本的sql语句 E5/-?(N
选择:select * from table1 where 范围 E[)`+:G]
插入:insert into table1(field1,field2) values(value1,value2) Z Z\,iT
删除:delete from table1 where 范围 I+kDx=T!
更新:update table1 set field1=value1 where 范围 %q`_vtUT
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! NoV)}fX$X8
排序:select * from table1 order by field1,field2 [desc] DnMfHG[<
总数:select count as totalcount from table1 K8ecSs}}J
求和:select sum(field1) as sumvalue from table1 HYZ94[Ti
平均:select avg(field1) as avgvalue from table1
(/-2bO
最大:select max(field1) as maxvalue from table1 /{."*jK
最小:select min(field1) as minvalue from table1 <A; R%\V
w|OMT>.
v\'Eo*4
Pp*|EW 1
11、说明:几个高级查询运算词 WIa4!\Ky!
\|L ~#{a
vxzh|uF
A: UNION 运算符 pGc_Klq
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。 %J5zfNe)&
B: EXCEPT 运算符 ^%VMp>s
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。 *[) b}?
C: INTERSECT 运算符 {AoH
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。 2bPrND\P=
注:使用运算词的几个查询结果行必须是一致的。 C1:efa<wV
12、说明:使用外连接 U^-:qT;CX
A、left outer join: 2,{m>fF
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。 %V%*0S|U
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 D'$ki[{,
B:right outer join: CE=&ZHt9
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。 y)0r%=
C:full outer join: b%IRIi&,
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。 .J6Oiv.E
%AwR 4"M
O-[ lL"T
二、提升 u]lf~EE
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) k|(uIU* ]
法一:select * into b from a where 1<>1 hX#y7m
法二:select top 0 * into b from a $!h21
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .DR^<Qy
insert into b(a, b, c) select d,e,f from b; ]?whx&+
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) C_mPw
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 u [5*RTE
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TcPYDAa
4、说明:子查询(表名1:a 表名2:b) 5V;BimI
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) b_ +dNoB
5、说明:显示文章、提交人和最后回复时间 9*pH[vH
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 3J%(2}{y
6、说明:外连接查询(表名1:a 表名2:b) 4E/Q+^?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c aKkL0D
7、说明:在线视图查询(表名1:a ) 2I(b ad
select * from (SELECT a,b,c FROM a) T where t.a > 1; |75>8;
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 F)Oe;z6
select * from table1 where time between time1 and time2 Z7a~M3VnZ
select a,b,c, from table1 where a not between 数值1 and 数值2 KAVe~j"
9、说明:in 的使用方法 `irz'/"p
select * from table1 where a [not] in ('值1','值2','值4','值6') }F=scbpXj
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8 h
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) L 1iA
^x
11、说明:四表联查问题: FW~%xUSE5
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 ..... $9k7A 8K
12、说明:日程安排提前五分钟提醒 8,d<&3D
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 DC4O@"
13、说明:一条sql 语句搞定数据库分页 |3j'HN5S
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Q}zAC2@L
14、说明:前10条记录 5i `q
select top 10 * form table1 where 范围 ~5g2~.&*
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) <mN.6@*{
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +0)s{?
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 +ExXhT
(select a from tableA ) except (select a from tableB) except (select a from tableC) E_k<EQ%r
17、说明:随机取出10条数据 GG@GjP<_
select top 10 * from tablename order by newid() 6a$=m3ic
18、说明:随机选择记录 W?is8r:
select newid() TN!8J=sx.
19、说明:删除重复记录 r1dP9MT\8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Jse;@K5y
20、说明:列出数据库里所有的表名 i8 t% v
select name from sysobjects where type='U' 2IDN?Mw
21、说明:列出表里的所有的 Vm\ly;v'R
select name from syscolumns where id=object_id('TableName') j_YpkKhen
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。 R{={7.As+
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 <=D!/7$O
显示结果: ?5@!r>i=<
type vender pcs www#.D%'U
电脑 A 1 tgeX~.
电脑 A 1 =SMI,p&
光盘 B 2 -CePtq`
光盘 A 2 .&Tcds
手机 B 3 N<XS-XB,
手机 C 3 KA^r,Iw
23、说明:初始化表table1 'VVEd[
TRUNCATE TABLE table1 ;QZ}$8D 6Q
24、说明:选择从10到15的记录 E&js`24 &
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @q8h'@sX
_OR@S%$
l@:|OGD;8
&USKudXmb
三、技巧 0i%r+_E_
1、1=1,1=2的使用,在SQL语句组合时用的较多 SbrKNADH%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 9*`(*>S
如: /XEt2,sI9
if @strWhere !='' p@`]9tLP(K
begin Zw4z`x1f
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /O@TqH
end _p<]jt
else aS2Mx~
begin <<#j?%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Lmp_8q-Ej
end YC,s]~[[
我们可以直接写成 (tY0 /s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere uB&um*DP
2、收缩数据库 RQg7vv]%
--重建索引 5SOl:{A+
DBCC REINDEX 1^R[kaY
DBCC INDEXDEFRAG v2ab
--收缩数据和日志 QY)hMo=|o8
DBCC SHRINKDB O:G5n 5J
DBCC SHRINKFILE e#{,M8
3、压缩数据库
:oN$w\A
dbcc shrinkdatabase(dbname) uu5L9.i9
4、转移数据库给新用户以已存在用户权限 )7`2FLG
exec sp_change_users_login 'update_one','newname','oldname' wgETL|3-
go nogdOGo
5、检查备份集 DAvF ND$=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Qf=+%-$Y
6、修复数据库 gjbSB6[
ALTER DATABASE [dvbbs] SET SINGLE_USER d<,'9/a>
GO L+GVB[@3Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK u[Ij4h.
GO >5%;NI5
G
ALTER DATABASE [dvbbs] SET MULTI_USER lPBWpHX
GO !=/wpsH
7、日志清除 $27QY
SET NOCOUNT ON N?Nu'
DECLARE @LogicalFileName sysname, ;1gWz
@MaxMinutes INT, 8?
U!PW
@NewSize INT 4Y.o RB
USE tablename -- 要操作的数据库名 _{k-&I
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 n^xB_DJ~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. wr`+xYuuC=
@NewSize = 1 -- 你想设定的日志文件的大小(M) kiP-^Wan
-- Setup / initialize ,SVl>~!
DECLARE @OriginalSize int q$ZmR]p
SELECT @OriginalSize = size &N+i3l6`
FROM sysfiles eI #b%h
WHERE name = @LogicalFileName He1hgJ)N
SELECT 'Original Size of ' + db_name() + ' LOG is ' + VMZUJ2Yj/&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <meQ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' p#QR^|7"
FROM sysfiles #'qDNY@ w}
WHERE name = @LogicalFileName 7]J7'!Iz
CREATE TABLE DummyTrans $URL7hrhU
(DummyColumn char (8000) not null) LA9'HC(5
DECLARE @Counter INT, $eSSW+8q"
@StartTime DATETIME, To!`
T$Xh
@TruncLog VARCHAR(255) |qAU\m"Pc
SELECT @StartTime = GETDATE(), 1x'H#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (p?7-~6|:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3_ P<0%
EXEC (@TruncLog) Yvn*evO4
-- Wrap the log if necessary. R?Ou=p
.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >@ : m#d
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) qRbU@o.3
AND (@OriginalSize * 8 /1024) > @NewSize \GP0FdpV
BEGIN -- Outer loop.
2m8|0E|@
SELECT @Counter = 0 g^mnYg5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) K'@lXA:
BEGIN -- update Z;"YUu[(
INSERT DummyTrans VALUES ('Fill Log') Hl*V i3bQU
DELETE DummyTrans -(FhjIr
SELECT @Counter = @Counter + 1 n@PXC8}
END f [DZ
EXEC (@TruncLog) *U}cj A:ZN
END QNcbl8@
SELECT 'Final Size of ' + db_name() + ' LOG is ' + `z!6zo2d
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !8@8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' g)**)mz[
FROM sysfiles ={k_
(8]
WHERE name = @LogicalFileName ,bRYqU?#0
DROP TABLE DummyTrans VLP'3 qX
SET NOCOUNT OFF Sdr,q9+__
8、说明:更改某个表
e&\+o}S
exec sp_changeobjectowner 'tablename','dbo' yBYZ? gc
9、存储更改全部表 v~AD7k2{8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch kBlk^=h<:w
@OldOwner as NVARCHAR(128), :<
*x G&
@NewOwner as NVARCHAR(128) 8iwH^+h~
AS n5z";:p
DECLARE @Name as NVARCHAR(128) b.#0{*/G
DECLARE @Owner as NVARCHAR(128) "">{8
DECLARE @OwnerName as NVARCHAR(128) >V$
S\"
DECLARE curObject CURSOR FOR ~R*01AnZ
select 'Name' = name, %s),4
'Owner' = user_name(uid) #!>QXiyR
from sysobjects 1x3>XN]a
where user_name(uid)=@OldOwner FE4P
EBXvu
order by name \<kQ::o1y
OPEN curObject {;^GKb+
FETCH NEXT FROM curObject INTO @Name, @Owner m> YjV>5
WHILE(@@FETCH_STATUS=0) LKsK!X
BEGIN =}OcMM`f
if @Owner=@OldOwner D6vhW:t8?
begin ('oA{,#L
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <HXzcWQ$
exec sp_changeobjectowner @OwnerName, @NewOwner >E\U$}WCG
end N${Wh|__^l
-- select @name,@NewOwner,@OldOwner OeYZLC(
FETCH NEXT FROM curObject INTO @Name, @Owner ltg\x8w?c
END hEk0MY
close curObject lDVw2J'p
deallocate curObject (4Ha'uqz
GO O3En+m~3n)
10、SQL SERVER中直接循环写入数据 xO
6$:o-
declare @i int Sh;Z\nj
set @i=1 | h%0)_
while @i<30 mXJ`t5v^l
begin s#4Q?<65u
insert into test (userid) values(@i)
PE&$2(
set @i=@i+1 #p7_\+&5s
end ::k
cV'*
小记存储过程中经常用到的本周,本月,本年函数 c1}i|7/XSi
Dateadd(wk,datediff(wk,0,getdate()),-1) 5XF&yYWq
Dateadd(wk,datediff(wk,0,getdate()),6) B"3uuk8
Dateadd(mm,datediff(mm,0,getdate()),0) ,c6c=di
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Z11I1)%s
Dateadd(yy,datediff(yy,0,getdate()),0) Jie=/:&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :S=!]la0h
上面的SQL代码只是一个时间段 B]wfDUG
Dateadd(wk,datediff(wk,0,getdate()),-1) 6e4A|<
Dateadd(wk,datediff(wk,0,getdate()),6) 5$%CRm
就是表示本周时间段. q?=_{oH9
下面的SQL的条件部分,就是查询时间段在本周范围内的: 7i0;Ss*
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (Nn)_caVb
而在存储过程中 (5efNugc
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) h{.x:pPXy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Ch7&9NW